Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects (2021)

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131   User’s Guide for Spreadsheet Tool 1 Spreadsheet Tool 1 is a spreadsheet-based benefit–cost analysis tool that can be used to assess the cost-effectiveness of specific improvement alternatives for implementation in conjunction with a resurfacing, restoration, and rehabilitation (3R) project. The tool helps users in making the decision as to whether the 3R project should consist of pavement resurfacing only or should also include geometric improvements. Tool 1 is used to assess one improvement alternative (or combination of alternatives) at a time. Tool 2, for which a user’s guide is presented in Appendix B, can assess multiple alternatives (and combinations of alternatives) in a single analysis. Both spreadsheet tools can be downloaded from the TRB website (trb.org) by searching for “NCHRP Research Report 876”. Tool 1 can be applied as part of the planning process for 3R projects. If a specific project site has no observed crash patterns or no traffic operational needs that would justify a design improvement, then implementation of geometric improvements as part of a 3R project would be recommended only if such improvements were anticipated to be cost-effective. Tool 1 pro- vides the capability to assess any particular improvement (or combination of alternatives) to determine whether it is anticipated to be cost-effective. Tool 1 addresses candidate 3R projects on rural two-lane highways, rural four-lane undivided and divided highways (nonfreeways), and rural and urban freeways. The tool does not address 3R projects on urban and suburban arterials (nonfreeways). Tool 1 is intended to address 3R projects with improvements that extend along continuous roadway segments as opposed to improvements at spot locations. For this reason, some typical 3R improvements, such as addition of turn lanes at individual intersections, are not evaluated in the tool. Intersection improvements are addressed in Section 4.3 and Sections 6.1 through 6.4 of the guidelines. While Tool 1 can be applied to evaluate a combination of several improvement alternatives, it can also be applied to evaluate those alternatives one at a time, to better understand their individual contributions to the overall effectiveness of the project. In addition, the structure of Tool 2 (see Appendix B) is such that it always evaluates each selected improvement alternative separately as well as all feasible combinations of the selected alternatives. The input data to Tool 1 include a description of the existing roadway conditions and selection by the user of the improvement(s) to be assessed. The tool considers a single set of AADT, terrain, and cross-section geometrics for the roadway between intersections within the candidate project being assessed. Variations in cross-section geometrics at intersections or on intersection approaches do not need to be considered in using the tool. Where there are minor variations in AADT on the project or in cross-section geometrics on the roadway between intersections within the project, use the average AADT and the most common cross-section geometrics as input to the tool. Thus, the tool can be applied even where the cross section throughout the A P P E N D I X A

132 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects project is not entirely homogeneous. Where there are major changes in cross-section geometrics on the roadway between intersections (e.g., half the project has 6-ft paved shoulders and half has 2-ft unpaved shoulders), the user can break the project into separate sections and analyze each section separately. Breaking the project into separate sections for analysis is only appropriate where the differences in cross-section geometrics are substantial. It is generally most appropriate to use the existing or current AADT value when applying Tool 1. Accounting for AADT growth over the service life of a project would also require that growth of other parameters over time (such as crash costs) be considered. This would require much more complicated analysis logic. Nevertheless, if a roadway is expected to have substantial traffic growth over the service life of a project, it is acceptable to assess the project benefit–cost ratio using the average AADT expected over the service life of the project. Tool 1 incorporates tips to provide an explanation to users about each data item they need to enter as input data to the tool. Hovering over the label of an input data item with the cursor displays an explanation of the item to be entered. Tool 1 includes logic to estimate the implementation cost of the improvement alternatives evaluated. The project costs are estimated from default values of unit construction costs that are built into the tool. Users have the option to change these default unit costs to match their agency’s experience or to replace the project cost estimated by the tool with the agency’s own site-specific estimate. The cost estimation logic assumes that each roadway, whether originally constructed with flexible or rigid pavement, will be overlaid with a flexible pavement surface (typically hot-mix asphalt) as part of the resurfacing project. The user also has the option for any given analysis as to whether to include the cost of right-of-way acquisition in the project implementation cost estimate. Right-of-way costs can also be based on default values built into the tool, user-specific unit costs for right-of-way, or site-specific cost estimates made by the agency. The safety performance of the roadway being analyzed and the safety benefits of improve- ment alternatives estimated in Tool 1 are based on the crash prediction procedures presented in Part C of the AASHTO Highway Safety Manual (HSM) including HSM Chapters 10, 11, and 18 (2, 3). The tool analyzes roadway segment (i.e., nonintersection) crashes only. The HSM crash prediction procedures are applied first to predict the crash frequencies by severity level for the existing roadway on the basis of safety performance functions (SPFs), crash modification factors (CMFs), and local calibration factors (if available). The crash reduction effectiveness of improve- ments is based on the CMFs presented in Section 4.3 of this guide. Users have the option to replace the default SPFs from the HSM with their own agency-specific SPFs for all roadway types other than freeways. The local calibration factor is set equal to 1.0 by default, but may be replaced at the user’s option with an agency-specific value. The user has the option to provide site-specific crash history data and apply the empirical Bayes (EB) method for converting predicted crash frequencies to expected crash frequencies by using the procedures presented in the appendix to HSM Part C (2). Crash costs by severity level are set by default to values built into the tool but may be replaced by the user with agency-specific values. The user of Tool 1 has the option to select which improvement alternative (or combination of alternatives) will be considered in the benefit–cost analysis. The improvement alternatives that may be considered include • Lane widening, • Shoulder widening (outside shoulder only on two-lane and four-lane nonfreeways; both outside and inside shoulders on freeways), • Shoulder paving (increasing the percentage of shoulder width that is paved; nonfreeways only),

User’s Guide for Spreadsheet Tool 1 133   • Roadside slope flattening (two-lane and four-lane nonfreeways only), • Centerline rumble strips (undivided highways only), • Shoulder rumble strips (outside shoulder only on undivided roads; both outside and inside shoulders on divided nonfreeways and freeways), • Enhanced striping/delineation (nonfreeways only), • Add or modify median barrier (freeways only), • Add or modify roadside barrier (freeways only), • Add passing lane(s) (rural two-lane highways only), • Improve/restore horizontal curve superelevation (nonfreeways only), and • Realign horizontal curve with increased radius (rural two-lane highways only). All of the alternatives considered in the tool represent an addition to, widening of, or flatten- ing of roadway or roadside features. Project alternatives that involve reducing the dimension of a roadway feature, such as reducing lane widths so that shoulders can be widened, can typically be accomplished for little additional cost in conjunction with a resurfacing project, so no formal economic analysis is needed for such alternatives. Guardrail installation or rehabilitation is not evaluated in Tool 1 for rural two-lane and multi- lane highways because no CMFs for guardrail installation or rehabilitation on these roadway types are available. Guardrail installation on these roadway types can be addressed with other tools such as the Roadside Safety Analysis Program (RSAP) (23–25), and is discussed in Sections 6.1.11, 6.2.11, 6.3.11, 6.4.7, and 6.5.5. While guardrail installation is not considered as an improvement alternative in the tool for rural two-lane and multilane highways, the cost of guardrail replacement is included, where appropriate, in the estimation of project costs for widening projects. Guardrail installation on freeways is addressed in Tool 1. The tool considers only roadway sections with shoulders and does not consider roadways with curb-and-gutter sections. Roadways with curb-and gutter sections are most common on urban and suburban arterials, which are not addressed by the tool. Resurfacing, restoration, and rehabili- tation projects on urban and suburban arterials are addressed in Section 6.4 of the guidelines. The results provided by Tool 1 for the analysis of any improvement alternative (or combina- tion of alternatives) include the following: • Project implementation cost (dollars), • Annual safety benefit (dollars), • Present value of safety benefit (dollars), • Benefit–cost ratio (benefit divided by cost), • Net benefit (benefit minus cost) (dollars), • Fatal and injury (FI) crashes per year in the before period, • Property-damage-only (PDO) crashes per year in the before period, • FI crashes per year in the after period, • PDO crashes per year in the after period, • FI crashes per year reduced by the project, and • PDO crashes per year reduced by the project. Tool 1 was developed entirely in Microsoft Excel worksheets without any supplementary Visual Basic programming. This should make Tool 1 easily implementable on computers with nearly any operating system and nearly any version of Microsoft Excel. By contrast, Tool 2, the user’s guide for which is presented in Appendix B, incorporates supplementary programming in Visual Basic; therefore, macros must be enabled on the user’s computer for Tool 2 to function. The user’s guide for Tool 1 is presented with separate sections on rural two-lane highways, rural four-lane highways, and freeways because the input data and improvement alternatives considered differ to some extent for each roadway type.

134 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects A1 Rural Two-lane Highways This section presents the application of Tool 1 to candidate 3R projects on rural two-lane highways. The guidance addresses setup defaults (which can be either accepted unchanged or modified by the user), data entry for existing conditions on a specific roadway, specifying the alternative(s) to be considered, reviewing analysis results, and reviewing calculations. A1.1 Setup Defaults Before performing any benefit–cost analyses, first visit the R2U_Setup worksheet. The purpose of the R2U_Setup worksheet is to establish default values for assessment of 3R projects on rural two-lane highways. The R2U_Setup worksheet contains default values for every non–site-specific data element needed by Tool 1 to perform the benefit–cost calculations. Thus, users can perform analyses without changing any values in the R2U_Setup worksheet. However, users have the option to modify any of the default values to other values that are consistent with their agency’s policies, practices, and experience. To change a default value, enter the modified value into the cell in the User Supplied column and click the option button in that cell. This user-supplied value will appear in the Values Used column as a replacement for the default value that was initially shown. The example in the screenshot in Figure A-1 shows that a user-supplied value of 1.5 ft has been entered for the average embankment height on level terrain and selected for use in the analysis. The default average embankment height values of 3.0 ft for rolling terrain and 4.5 ft for mountainous terrain have not been changed and will be used in the analysis. Each of the data elements on the R2U_Setup worksheet is described in the following sections. A1.1.1 Road Elements Figure A-2 shows a screenshot of the road element defaults. Each item in the figure is discussed below. • Average Embankment Height: Average representation of the embankment height of the roadway cross section in feet for level, rolling, and mountainous terrain. The default values of average embankment height are based on estimates developed by Zegeer et al. (31). • Existing Base Depth: Depth in inches of base material underneath the traveled way and shoulder. • Milling Depth: Depth in inches to which flexible pavement of traveled way and shoulder will be milled as part of pavement resurfacing. This applies only to flexible pavement. Figure A-1. Specifying values in the R2U_Setup worksheet to be used as estimates of average embankment height for specific terrain types.

User’s Guide for Spreadsheet Tool 1 135   • Pavement Depth: Depth in inches of flexible pavement for traveled way and shoulder. This applies only to flexible pavement. • Average Delineator Spacing: Average spacing in feet between roadside delineators, where delineators are to be added. The contents of this field are considered only when enhanced striping delineation is selected as an alternative to consider and total length of section with delineator posts is set to a value greater than zero. If no delineators are being added, the average delineator spacing can be left equal to the default value of 500 ft or equal to any user-supplied value, and this will not affect the results. A1.1.2 Cost Elements The screenshots shown in Figures A-3 and A-4 show the cost element defaults for rural two-lane highways. Each cost element is discussed in detail below. All costs are in dollars. • Base Unit Cost: Cost of base material per cubic yard. • Milling Unit Cost: Cost of pavement milling per square yard. • Flexible Pavement Unit Cost: Material and installation cost of flexible pavement per cubic yard. Some agencies specify costs for placement of hot-mix asphalt overlays on a per-ton basis; per-ton costs should be converted to a per-cubic-yard basis for entry in Figure A-3. • Rigid Pavement Unit Cost: Material and installation cost of rigid pavement per square yard. • Unpaved Shoulder Unit Cost: Material and installation cost of unpaved shoulder per square yard. • Embankment Unit Cost: Cost of embankment material per cubic yard. • Right-of-way Unit Cost: Cost of acquiring right-of-way per acre. • Centerline Rumble Strip Unit Cost: Cost of installing a centerline rumble strip per linear foot. • Shoulder Rumble Strip Unit Cost: Cost of installing a shoulder rumble strip per linear foot. • Durable Pavement Marking Unit Cost: Material and installation cost of a durable pavement marking per linear foot. • Delineator Cost: Material and installation cost of one roadside delineator. • Incidentals: Each incidental cost is calculated as a percentage of the project total cost, not including the right-of-way cost. – Signing and PM: Signing and pavement markings. Figure A-2. Defaults for road elements for rural two-lane highways.

136 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Figure A-3. Defaults for cost elements for rural two-lane highways, Part 1 of 2. Figure A-4. Defaults for cost elements for rural two-lane highways, Part 2 of 2.

User’s Guide for Spreadsheet Tool 1 137   • MARR/discount rate: Minimum attractive rate of return (MARR) for analysis of 3R project investments. Federal guidelines suggest an MARR value at 7%. The MARR is also referred to as the “discount rate.” • Service Life: Expected useful life or service life in years for the roadway improvement. – Slope Flattening: Service life of slope flattening, including flattening the roadside foreslope only. – Lane Widening: Service life for widening of the traveled way. – Shoulder Widening: Service life for widening of the shoulder adjacent to the traveled way. Note: Slope flattening, lane widening, and shoulder widening should always be assigned identical service lives. This service life is also used for horizontal curve realignment. – Rumble Strip Installation: Service life of centerline and shoulder rumble strips. – Striping/Delineation: Service life of roadway striping and roadside delineators. – Superelevation Restoration: Service life of restoring or changing horizontal curve super- elevation. • Crash Cost by Severity: Societal crash costs by crash severity level. Crash severity levels are defined in a manner consistent with the HSM. – Fatal: Cost of a fatal crash. – Disabling Injury: Cost of a disabling injury crash. – Evident Injury: Cost of an evident injury crash. – Possible Injury: Cost of a possible injury crash. – Property Damage Only: Cost of a property-damage-only crash. A1.1.3 Safety Elements Figure A-5 shows a screenshot the safety element defaults for rural two-lane highways. Each element is discussed in detail below. The crash type and crash severity categories used as defaults are the categories used in the HSM. • Rural 2-lane SPF: The user has the option to retain the SPF applicable to rural two-lane highways from HSM Chapter 10 or to modify it. The SPF used in the HSM for rural two-lane highways is a function of AADT and roadway section length, as follows: predicted crash frequency = AADT × length × 365 × 10−6e−0.312 • Users can supply their own SPF as a function of AADT and roadway section length. An example of how to enter a revised SPF is illustrated in the screenshot shown in Figure A-6. In the cell provided (Cell I74 in the R2U_Setup worksheet), type in a formula that is a function of cells I70 and I72, which represent AADT and roadway section length, respec- tively. Enter the overdispersion parameter for the rural two-lane SPF in cell I75. • Calibration Factor: This is a factor to adjust crash frequency estimates produced from the safety prediction procedure to approximate the agency’s local conditions. A default value of 1.0 is built into the tool. • Crash Type Proportion: This is the percentage of all crashes for each crash type shown. Default values of these percentages from HSM Chapter 10 are built into the tool. The user may also enter agency-specific values. All percentages must add to 100%. If the sum of all percentages is between 95% and 105%, then the tool will automatically adjust each individual percentage proportionally to add to 100%. The tool will not consider user-supplied percent- ages if the sum of all percentages is less than 95% or greater than 105%. In this case, an error message will be displayed. • Crash Severity Proportion: This is the percentage of all crashes for each crash severity level. Default values of these percentages from HSM Chapter 10 are built into the tool. The user may also enter agency-specific values. All percentages must add to 100%. If the sum of all percentages

138 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Figure A-5. Defaults for safety elements for rural two-lane highways. Figure A-6. Specify an agency-specific SPF for rural two-lane highways. is between 95% and 105%, then the tool will adjust each individual percentage proportionally to add to 100%. The tool will not consider user-supplied percentages if the sum of all percentages is less than 95% or greater than 105%. In this case, an error message will be displayed. • Custom CMF Values for Total Crashes: User-supplied CMFs may be entered only for treatments for which the CMF is a single tabulated value (i.e., not an equation) and applies to total crash frequency. For rural two-lane highways, these treatments include centerline rumble strips and enhanced striping and delineation.

User’s Guide for Spreadsheet Tool 1 139   A1.2 Data Entry After the setup defaults have been either retained or modified, as the user wishes, the tool is ready to perform benefit–cost analyses for rural two-lane highways. Proceed to the R2U_Project worksheet. Use the R2U_Project worksheet to enter all existing roadway attributes and select specific improvements to consider in the benefit–cost analysis. The following sections step through each input data entry form in the R2U_Project worksheet. A1.2.1 Roadway Data Roadway data for the candidate 3R project site to be assessed are entered in the data entry form shown in Figure A-7. • Section Length: Length in miles of the roadway section. • AADT: Annual average daily traffic volume in vehicles per day for two-way traffic on the roadway section. This typically represents the existing or current AADT for the roadway being analyzed. Where substantial future AADT growth is expected, the average AADT over the anticipated project service life may be used. • Terrain: The terrain in which the roadway section is located. • Pavement Type: Type of pavement of the roadway section, either flexible or rigid. A1.2.2 Alignment Data The Alignment Data entry form shown in the screenshot in Figure A-8 addresses the method that will be used to describe the horizontal curvature of the roadway section of interest. Use the option buttons in Figure A-8 to select either entry of average curve data or entry of specific curve data. Depending on which option button is selected, different entry forms will appear on the worksheet. Note that if the user plans on considering superelevation restoration/ improvement as part of the 3R project, the user must enter specific curve data. Figure A-7. Roadway Data entry form for rural two-lane highways. Figure A-8. Alignment Data entry options for rural two-lane highways.

140 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects The following two figures show the data entry for average curve data (Figure A-9) and specific curve data (Figure A-10). Note that the user will only see the data entry form corresponding to the option that has been chosen for entering alignment data. • % of Section Length on Curves: Enter the percentage of the roadway section that is on horizontal curves. Include spiral transitions in the percentage if present. • Typical Curve Radius: Enter the average horizontal curve radius of the roadway section. • Number of Curves on Section: Enter the number of horizontal curves on the roadway section. • Presence of Spiral Transitions: If spiral transitions are present with the horizontal curves, use the drop-down in this cell to select Yes. Otherwise, select No. • Number of Curves in Roadway Section: Enter the number of horizontal curves that exist on the roadway section. A maximum of 10 curves can be entered in the specific curve data form. If more than 10 curves need to be considered, the roadway section may be split into shorter sections for analysis. If there are no curves or the user does not wish to consider superelevation improvement as an option for the 3R project, then enter “0” for number of curves. • Maximum Superelevation Rate (emax): Enter the agency’s maximum superelevation rate for horizontal curves on rural two-lane highways. • Design Speed: Enter the design speed of the roadway section in miles per hour. The user should enter the following data for each horizontal curve on the roadway section: • Curve Length: Enter the length of horizontal curve in miles, not including spiral transitions. • Transition Length: Enter the length of spiral transition in miles for one end of the horizontal curve. If there are no spiral transitions, enter “0.” Figure A-9. Average Curve Data entry form for rural two-lane highways. Figure A-10. Specific Curve Data entry form for rural two-lane highways.

User’s Guide for Spreadsheet Tool 1 141   • Radius: Enter the radius of the horizontal curve in feet. • Spiral: Select Yes from the embedded drop-down menu if spiral curves are present. Otherwise, select No. • Existing e: Enter the existing superelevation rate of the horizontal curve, expressed as a percentage. • Consider for Improvement: Select Yes from the embedded drop-down menu if the user wants to consider superelevation restoration/improvement on this specific curve in the 3R project. Otherwise, select No. • Improved e: If Yes was selected in the Consider for Improvement column, then the Improved e cell will be shown. Enter the improved superelevation rate of the horizontal curve as a percentage. A1.2.3 Existing Cross Section Data Use the Existing Cross Section data entry form shown in Figure A-11 to define the following features of the roadway section: • Lane Width: Select the existing average lane width on the traveled way in feet from the drop-down menu. • Shoulder Width: Select the existing average shoulder width in feet from the drop-down menu. This represents total shoulder width, including any paved or unpaved shoulders. • Proportion of Shoulder Width that is Paved: Enter the proportion of the shoulder width that is paved. This should be a value in the range from 0 to 1, inclusive. Enter “0” for a shoulder whose entire width is unpaved. Enter “1” for a shoulder whose entire width is paved. Enter an appropriate value between 0 and 1 for a composite shoulder (i.e., a shoulder whose width is partly paved and partly unpaved). • Roadside Slope: Select the existing roadside foreslope from the drop-down menu. Only constant foreslopes are considered. The foreslopes included in the drop-down menu (1V:2H, 1V:3H, 1V:4H, and 1V:6H) are those used in the research on which the CMF for roadside slope is based (22). Foreslopes that vary in steepness with distance from the traveled way are not considered because no CMFs are available for such composite slopes. • Centerline Rumble Strip: Select Yes from the drop-down menu if centerline rumble strips exist on the roadway section. Otherwise, select No. • Shoulder Rumble Strip: Select Yes from the drop-down menu if shoulder rumble strips exist on the roadway section. Otherwise, select No. It should be noted that shoulder rumble strips may be selected even where unpaved shoulders are present, because the rumble strip may be placed on the edgeline of the traveled way. Lane Width (ft) Shoulder Width (ft) Proportion of Shoulder Width that is Paved 0 Roadside Slope Centerline Rumble Strip Shoulder Rumble Strip EXISTING CROSS SECTION Figure A-11. Existing Cross Section data entry for rural two-lane highways.

142 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects A1.2.4 Crash History Option The user can choose to use the existing site-specific crash history of the roadway section to assist in calculating potential crash savings with the 3R project. Otherwise, the user can simply use the estimate given by the HSM crash prediction method. The choice between these options is made in the form shown in Figure A-12. The advantage of using site-specific crash history is that the benefit estimate may better reflect local conditions. • Consider existing crash history?: Select Yes to use the site-specific crash history for the roadway section. Otherwise, select No. The Crash Data entry form, shown in Figure A-13, will appear when Yes is selected for the consideration of existing crash history. • Crash History Period: Enter the number of years of available crash data. • Total Fatal-and-Injury Crashes: Enter the total number of crashes on the roadway segment that fall into the following crash severity levels: – Fatal crash, – Disabling injury crash, – Evident injury crash, and – Possible injury crash. • Total Property-Damage-Only Crashes: Enter the total number of crashes on the roadway segment that fall into the property-damage-only crash severity level. A1.3 Alternatives to Consider Near the bottom of the R2U_Project worksheet is a data entry form in which to specify which improvement alternatives should be considered in the benefit–cost analysis (Figure A-14). Check the appropriate checkboxes to select the improvement alternatives to consider in the analysis. Tool 1 lends itself readily to sensitivity analyses considering specific improvement alterna- tives by themselves or in combination. The user can easily check and uncheck the boxes for specific improvement alternatives shown in Figure A-14 and quickly rerun the benefit–cost analysis with or without including specific improvement alternatives. Furthermore, Tool 2 (see Appendix B) automatically evaluates each improvement alternative separately as well as all feasible combinations of the selected alternatives. Figure A-12. Crash History option data entry form for rural two-lane highways. Figure A-13. Crash Data entry form for rural two-lane highways.

User’s Guide for Spreadsheet Tool 1 143   Each potential improvement alternative that can be selected is described below in more detail. • Lane Width: If the Lane Width box has been checked, select the width to which the through travel lanes will be widened from the choices offered on the drop-down menu in the User Selection column. Only values greater than the existing lane width can be selected, up to a maximum lane width of 12 ft. • Shoulder Width: If the Shoulder Width box has been checked, select the width to which the shoulders will be widened from the choices offered on the drop-down menu in the User Selection column. Only values greater than the existing shoulder width can be selected, up to a maximum shoulder width of 8 ft. • Modify Proportion of Shoulder Width that is Paved: If the Modify Proportion of Shoulder Width that is Paved box has been checked, enter the modified paved shoulder proportion value in the User Selection box. Modified proportions that decrease the width of the shoulder that is paved cannot be entered. • Roadside Slope: If the Roadside Slope box has been checked, select the improved roadside slope from the drop-down menu in the User Selection column. Only slopes flatter than the existing roadside slope can be selected. The flattest slope that may be considered is 1V:6H. Flattening of roadside slopes is not considered as an improvement alternative for freeways because no generally accepted CMFs are available for this alternative. • Centerline Rumble Strip: If the Centerline Rumble Strip box has been checked, no further data entry is necessary. Installation of a centerline rumble strip along the entire length of the roadway section will be considered. Note that if a centerline rumble strip already exists on the roadway section, checking the centerline rumble strip box will have no effect. In this case, the cost of installing the rumble strip after repaving will automatically be added to the project cost of the 3R project. • Shoulder Rumble Strip: If the Shoulder Rumble Strip box has been checked, no further data entry is necessary. Installation of a shoulder rumble strip along the entire length of both sides of the roadway section will be considered. Note that if a shoulder rumble strip already exists on the roadway section, checking the shoulder rumble strip box will have no effect. 1 Lane Width (ft) Retain Lane Width Shoulder Width (ft) Retain Shoulder Width Modify Proportion of Shoulder Width that is Paved 0 Roadside Slope Retain Roadside Slope Centerline Rumble Strip Retain Centerline Rumble Strip Shoulder Rumble Strip Retain Shoulder Rumble Strip Enhanced Striping/Delineation Not Selected Add New Passing Lane(s) Not Selected Alternatives to Consider User Selection Consider for Improvement Value Selected Figure A-14. Data entry form to select alternatives to consider for rural two-lane highways.

144 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects In this case, the cost of installing the rumble strip after repaving will automatically be added to the project cost of the 3R project. • Enhanced Striping/Delineation: If the Enhanced Striping/Delineation box has been checked, installation of durable pavement markings will be considered for both centerline and edge striping. The data entry form shown in Figure A-15 will appear if this option is selected. Installation of roadside delineators will also be considered if the Total Length of Section with Delineator Posts field in Figure A-15 is set to a value larger than zero. • % of Section with Dashed Centerline: Enter the percentage of the roadway section in which the centerline striping is dashed only. • % of Section with Solid–Dash Centerline: Enter the percentage of the roadway section in which the centerline striping is a solid–dash combination. • % of Section with Double Solid Centerline: Enter the percentage of the roadway section in which the centerline striping is double-solid. • Total Length of Section with Delineator Posts: Enter the length of the roadway section in miles that will have roadside delineator posts. Include both sides of the roadway separately (i.e., enter 2 mi if a 1-mi roadway section will have roadside delineators on both sides of the roadway). • Add New Passing Lane(s): If the Add New Passing Lane(s) box has been checked, addition of one or more new passing lanes will be considered. The data entry form shown in Figure A-16 will appear if this option is selected. Figure A-15. Enhanced Pavement Marking and Delineation Data entry form for rural two-lane highways. Figure A-16. Passing Lane Data entry form for rural two-lane highways.

User’s Guide for Spreadsheet Tool 1 145   • Number of New Passing Lanes in Roadway Section: Enter the number of passing lanes that will be added to the roadway section. Passing lanes in each direction of travel are counted separately. Each passing lane should be determined to be operationally justified before being considered in this tool. • Design Speed: Enter the design speed of the new passing lanes in miles per hour. • New Length of Passing Lanes in Road Section: Enter the total length in miles of new passing lanes to be added to the roadway section. The length of each passing lane is measured from the beginning of the lane addition taper to the end of the lane drop taper of the passing lane. If more than one passing lane is added, sum the passing lane lengths. • New Length of Overlapping Passing Lanes: Enter the total roadway length in miles in which passing lanes on both sides of the roadway overlap. • Width of New Passing Lanes: Enter the lane width in feet of the new passing lanes. Superelevation improvements to horizontal curves are selected for consideration not by checking a box in the data entry form shown in Figure A-14, but rather by selecting Yes in the Consider for Improvement column in the data entry form shown in Figure A-10 for horizontal curves whose superelevation potentially needs improvement. Tool 1 includes the capability to evaluate an alternative involving realignment of a horizontal curve. This alternative applies to rural two-lane highways only. Horizontal curve realignment is not selected for consideration by checking a box in the data entry form shown in Figure A-14. Rather, a separate worksheet is used to evaluate horizontal curve realignment, as described in Section A4. A1.4 Comments/Notes The R2U_Project worksheet includes a Comments/Notes field into which the user can enter and retain a record of any project- or site-specific information that helps explain the issues being addressed with the tool. The information entered in the Comments/Notes field will be saved whenever the Tool 1 workbook as a whole is saved. A similar Comments/Notes field is included in the results section of the tool. A1.5 Analysis Results The results of the benefit–cost analysis are shown in the Results summary at the top of the R2U_Project worksheet (Figure A-17). The Results summary presents the following information: • PV Modified Total Cost: The total project cost of the project is the best available estimate of the cost to construct the project, including incidental expenses. The cost estimated Figure A-17. Results of benefit–cost analysis for rural two-lane highways.

146 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects calculated by the tool is based on default or user-supplied values for the unit costs shown in Figure A-3 and the incidental cost percentages shown in Figure A-4. The calculated project cost is estimated on the basis of typical or average conditions for a location without unusual project- or site-specific features that could affect the implementation cost. For example, the cost of superelevation restoration may vary from typical values according to whether adjust- ments to shoulders or embankments are needed. Where lane or shoulder widening occurs, the cost estimate assumes that all features outside the widened element need to be rebuilt. However, the cost estimate assumes that the portion of the existing lanes and shoulders not affected by the widening will be retained. As noted below, users may choose to use the project cost calculated by the tool or may supply their own estimate of the project cost: – Calculated: The present value of the modified total project cost is shown in this cell. The modified total cost is the total project cost not including the cost of milling and resurfacing the existing traveled way. – User Supplied: Users may supply their own total project cost in this cell. As for the calculated value, the user-supplied project cost should exclude the cost of milling and resurfacing the existing traveled way. Click the option button in this cell for the tool to use this user-supplied total cost in place of the value calculated by the tool. • Annual Safety Benefit: This is the calculated annual crash savings in dollars that is esti- mated to result from the selected 3R project roadway improvements (other than milling and resurfacing, which will be implemented whether or not the other improvements are made). • Present Value of Safety Benefit: This is the present value of the annual crash savings over the service life of the roadway improvements. • Benefit–Cost Ratio: The benefit–cost ratio is the ratio of the present value of safety benefit divided by the present value of the modified total cost. • Net Benefit: The net benefit is the present value of safety benefit minus the present value of the modified total cost. The annual number of crashes predicted before and after the 3R project, along with the annualized crash reductions, are shown to the right of the Results summary in the R2U_Project worksheet (Figure A-18). A1.6 View Calculations The user may access the R2U_Calculations worksheet to review all of the intermediate values calculations in assessing the benefits and costs of the project. This is a read-only worksheet that enables the user to review the calculations; it does not allow the user to change any results. Figure A-18. Crash frequencies before and after 3R project for rural two-lane highways.

User’s Guide for Spreadsheet Tool 1 147   A2 Rural Four-Lane Highways This section presents the application of Tool 1 to candidate 3R projects on rural four-lane undivided and divided highways. The guidance addresses setup defaults (which can be either accepted unchanged or modified by the user), data entry for existing conditions on a specific roadway, specifying the alternative(s) to be considered, reviewing analysis results, and reviewing calculations. A2.1 Setup Defaults Before performing any benefit–cost analyses for rural four-lane highways, first visit the R4UD_Setup worksheet. The purpose of the R4UD_Setup worksheet is to establish default values for assessment of 3R projects on rural four-lane undivided and divided highways (nonfreeways). The R4UD_Setup worksheet contains default values for every non–site-specific data element needed by Tool 1 to perform the benefit–cost calculations. Thus, the user can perform analyses without changing any values in the R4UD_Setup worksheet. However, the user has the option to modify any of the default values to other values that are consistent with the agency’s policies, practices, and experience. To change a default value, enter the modified value into the cell in the User Supplied column and click the option button in that cell. This user-supplied value will appear in the Values Used column as a replacement for the default value that was initially shown. Each of the data elements on the R4UD_Setup worksheet is described in the following sections. A2.1.1 Road Elements Figure A-19 shows a screenshot of the road element defaults. Each item in the figure is discussed below. • Average Embankment Height: Average representation of the embankment height of the roadway cross section in feet for level, rolling, and mountainous terrain. The default values of average embankment height are based on estimates developed by Zegeer et al. (31). • Existing Base Depth: Depth in inches of base material underneath the traveled way and shoulder. • Milling Depth: Depth in inches to which flexible pavement of traveled way and shoulder will be milled as part of pavement resurfacing. This applies only to flexible pavement. • Pavement Depth: Depth in inches of flexible pavement for traveled way and shoulder. This applies only to flexible pavement. • Average Delineator Spacing: Average spacing in feet between roadside delineators, where delineators are to be added. A2.1.2 Cost Elements Figures A-20 and A-21 show screenshots of the cost element defaults for rural multilane highways. Each element is discussed in detail below. All costs are in dollars. • Base Unit Cost: Cost of base material per cubic yard. • Milling Unit Cost: Cost of pavement milling per square yard. • Flexible Pavement Unit Cost: Material and installation cost of flexible pavement per cubic yard.

148 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Figure A-19. Entry form for road element defaults for rural four-lane highways. Figure A-20. Entry form for cost element defaults for rural four-lane highways, Part 1 of 2.

User’s Guide for Spreadsheet Tool 1 149   • Rigid Pavement Unit Cost: Material and installation cost of rigid pavement per square yard. • Unpaved Shoulder Unit Cost: Material and installation cost of unpaved shoulder per square yard. • Embankment Unit Cost: Cost of embankment material per cubic yard. • Right-of-way Unit Cost: Cost of acquiring right-of-way per acre. • Centerline Rumble Strip Unit Cost: Cost of installing a centerline rumble strip per linear foot. • Shoulder Rumble Strip Unit Cost: Cost of installing a shoulder rumble strip per linear foot. • Durable Pavement Marking Unit Cost: Material and installation cost of a durable pavement marking per linear foot. • Delineator Cost: Material and installation cost of one roadside delineator. • Incidentals: Each incidental cost is calculated as a percentage of the project total cost, not including the right-of-way cost. – Signing and PM: Signing and pavement markings. • MARR/discount rate: Minimum attractive rate of return (MARR) for analysis of 3R project investments. Federal guidelines suggest an MARR value at 7%. The MARR is also referred to as the “discount rate.” • Service Life: Expected useful life or service life in years for the roadway improvement. – Slope Flattening: Service life for slope flattening, including flattening the roadside foreslope only. – Lane Widening: Service life for widening of the traveled way. – Shoulder Widening: Service life for widening of the shoulder adjacent to the traveled way. Note: Slope flattening, lane widening, and shoulder widening should always be assigned identical service lives. Figure A-21. Entry form for cost element defaults for rural four-lane highways, Part 2 of 2.

150 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects – Rumble Strip Installation: Service life of centerline and shoulder rumble strips. – Striping/Delineation: Service life of roadway striping and roadside delineators. – Superelevation Restoration: Service life of restoring or changing horizontal curve super- elevation. • Crash Cost by Severity: Societal crash costs by crash severity level. Crash severity levels are defined in a manner consistent with the HSM. – Fatal: Cost of a fatal crash. – Disabling Injury: Cost of a disabling injury crash. – Evident Injury: Cost of an evident injury crash. – Possible Injury: Cost of a possible injury crash. – Property Damage Only: Cost of a property-damage-only crash. A2.1.3 Safety Elements Figures A-22 through A-25 show screenshots of the safety element defaults for rural four-lane highways. Each element is discussed in detail below. • Rural 4-lane Undivided SPF: The user has the option to retain the SPF applicable to rural four-lane undivided highways (nonfreeways) from HSM Chapter 11 or to modify it. The SPF used in the HSM for rural four-lane undivided highways is predicted crash frequency = e−9.653+1.176ln(AADT)+ln(length) Users can supply their own SPF as a function of AADT and roadway section length. An example of how to enter a revised SPF is shown in the screenshot in Figure A-23. In the cell provided (Cell I72 in the R4UD_Setup worksheet), type in a formula that is a function of cells I70 and I71, which are the AADT and roadway section length, respectively. Enter the overdispersion parameter for the rural four-lane undivided SPF in Cell I73. • Rural 4-lane Divided SPF: The user has the option to retain the SPF applicable to rural four- lane divided highways (nonfreeways) from HSM Chapter 11 or to modify it. The SPF used in the HSM for rural four-lane divided highways is predicted crash frequency = e−9.025+1.049ln(AADT)+ln(length) Users can supply their own SPF as a function of AADT and roadway section length (see Figure A-23). In the cell provided (Cell I80), type in a formula that is a function of cells I78 and I79, which are AADT and roadway section length, respectively. Enter the overdispersion parameter for the rural four-lane divided SPF in Cell I81. • Calibration Factor: This is a factor to adjust crash frequency estimates produced from the safety prediction procedure to approximate the agency’s local conditions. A default value of 1.0 is built into the tool. Figure A-22. Entry form for safety element defaults for rural four-lane highways, Part 1 of 3.

User’s Guide for Spreadsheet Tool 1 151   Figure A-23. User-specified SPFs for rural four-lane highways. Figure A-24. Entry form for safety element defaults for rural four-lane highways, Part 2 of 3.

152 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects • Crash Type Proportion: This is the percentage of all crashes for each crash type shown. Default values of these percentages from HSM Chapter 11 are built into the tool. The user may also enter agency-specific values. All percentages must add to 100%. If the sum of all percentages is between 95% and 105%, then the tool will automatically adjust each individual percentage proportionally to add to 100%. The tool will not consider user-supplied percent- ages if the sum of all percentages is less than 95% or greater than 105%. In this case, an error message will be displayed. • Crash Severity Proportion: This is the percentage of all crashes for each crash severity level. Default values of these percentages from HSM Chapter 11 are built into the tool. The user may also enter agency-specific values. All percentages must add to 100%. If the sum of all percentages is between 95% and 105%, then the tool will adjust each individual percentage proportionally to add to 100%. The tool will not consider user-supplied percentages if the sum of all percentages is less than 95% or greater than 105%. In this case, an error message will be displayed. • Custom CMF Values for Total Crashes: User-supplied CMFs may be entered only for treatments where the CMF is a single value and applies to total crash frequency. For rural multilane undivided highways, these treatments include centerline rumble strips and enhanced striping and delineation. For rural multilane divided nonfreeways, these treatments include only enhanced striping and delineation. A2.2 Data Entry After the setup defaults have been either retained or modified, as the user wishes, the tool is ready to perform benefit–cost analyses for rural four-lane highways. Proceed to the R4UD_Project worksheet. Figure A-25. Entry form for safety element defaults for rural four-lane highways, Part 3 of 3.

User’s Guide for Spreadsheet Tool 1 153   Use the R4UD_Project worksheet to enter all existing roadway attributes and select roadway improvements to consider in the benefit–cost analysis. The following sections step through each data entry form in the R4UD_Project worksheet. A2.2.1 Roadway Data The screenshot in Figure A-26 shows the Roadway Data entry form for rural four-lane highways. • Divided or Undivided: Select either 4-lane Undivided or 4-lane Divided from the drop-down menu. • Section Length: Length in miles of the roadway section. • AADT: Annual average daily traffic volume in vehicles per day for two-way traffic on the roadway section. This typically represents the existing or current AADT for the roadway being analyzed. Where substantial future AADT growth is expected, the average AADT over the anticipated project service life may be used. • Terrain: The terrain in which the roadway section is located. • Pavement Type: Type of pavement of the roadway section, either flexible or rigid. A2.2.2 Alignment Data Alignment data represent the horizontal curvature on the roadway section of interest. Unlike the rural two-lane highway procedures, there is no need for an average curve data option for rural four-lane nonfreeways. For rural four-lane nonfreeways, alignment data are used only for the assessment of superelevation improvements. If there are no curves on the roadway section of interest or the user does not wish to consider superelevation improvement as an option for the 3R project, then “0” is entered for Number of Curves in Roadway Section (see Figure A-27). • Number of Curves in Roadway Section: Enter the number of horizontal curves that exist on the roadway section. A maximum of 10 curves can be entered in the specific curve data form. If more than 10 curves need to be considered, the roadway section may be split into shorter sections for analysis. If there are no curves or the user does not wish to consider superelevation improvement as an option for the 3R project, then “0” is entered as the number of curves. • Maximum Superelevation Rate (emax): Enter the agency’s maximum superelevation rate on rural multilane highways. • Design Speed: Enter the design speed of the roadway section in miles per hour. The user should enter the following data for each horizontal curve on the roadway section: • Curve Length: Enter the length of horizontal curve in miles, not including spiral transitions. • Transition Length: Enter the length of spiral transition in miles for one end of the horizontal curve. If there are no spiral transitions, enter “0”. Figure A-26. Roadway Data entry form for rural four-lane highways.

154 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects • Radius: Enter the radius of the horizontal curve in feet. • Spiral: Select Yes from the embedded drop-down menu if spiral curves are present. Otherwise, select No. • Existing e: Enter the existing superelevation rate of the horizontal curve expressed as a percentage. • Consider for Improvement: Select Yes from the embedded drop-down menu to consider superelevation restoration/improvement on this specific curve in the 3R project. Otherwise, select No. • Improved e: If Yes has been selected in the Consider for Improvement column, then the Improved e cell will be shown. Enter the improved superelevation rate of the horizontal curve as a percentage. A2.2.3 Existing Cross Section Data Use the Existing Cross Section data entry form shown in Figure A-28 to define the following features of the roadway section: • Lane Width: Select the existing lane width on the traveled way in feet from the drop-down menu. • Shoulder Width: Select the existing shoulder width in feet from the drop-down menu. • Proportion of Shoulder Width that is Paved: Enter the proportion of shoulder width that is paved. This should be a value in the range from 0 to 1, inclusive. Enter “0” for a shoulder whose entire width is unpaved. Enter “1” for a shoulder whose entire width is paved. Enter an appropriate value between 0 and 1 for a composite shoulder (i.e., a shoulder whose width is partly paved and partly unpaved). • Roadside Slope: Select the existing roadside foreslope from the drop-down menu. Figure A-27. Specific Curve Data entry form for rural four-lane highways. Lane Width (ft) Shoulder Width (ft) Proportion of Shoulder Width that is Paved 1 Roadside Slope Centerline Rumble Strip Shoulder Rumble Strip EXISTING CROSS SECTION Figure A-28. Existing Cross Section data entry form for rural four-lane highways.

User’s Guide for Spreadsheet Tool 1 155   • Centerline Rumble Strip: Select Yes from the drop-down menu if centerline rumble strips exist on the roadway section. Otherwise, select No. • Shoulder Rumble Strip: Select Yes from the drop-down menu if shoulder rumble strips exist on the roadway section. Otherwise, select No. It should be noted that shoulder rumble strips may be selected even where unpaved shoulders are present because the rumble strip may be placed on the edgeline of the traveled way. A2.2.4 Crash History Option The user can choose to use the existing site-specific crash history of the roadway section to assist in calculating potential crash savings with the 3R project. Otherwise, the user can simply use the estimate given by the HSM crash prediction method. The choice between these options is made in the data entry form shown in Figure A-29. The advantage of using site-specific crash history is that the benefit estimate may better reflect local conditions. • Consider existing crash history?: Select Yes to use the crash history for the roadway section. Otherwise, select No. The Crash Data entry form shown in the screenshot in Figure A-30 will appear when Yes is selected for the consideration of existing crash history. • Crash History Period: Enter the number of years of available crash data. • Total Fatal-and-Injury Crashes: Enter the total number of crashes on the roadway segment that fall into the following crash severity levels: – Fatal crash, – Disabling injury crash, – Evident injury crash, and – Possible injury crash. • Total Property-Damage-Only Crashes: Enter the total number of crashes on the roadway segment that fall into the property-damage-only crash severity level. A2.3 Alternatives to Consider Near the bottom of the R4UD_Project worksheet is a data entry form in which to specify which alternatives should be considered in the benefit–cost analysis (see Figure A-31). Check the appropriate checkboxes to select the improvement alternatives to consider in the analysis. Figure A-29. Crash History option data entry form for rural four-lane highways. Figure A-30. Crash Data entry form for rural four-lane highways.

156 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Each potential improvement alternative is described in more detail below. • Lane Width: If the Lane Width box has been checked, select the width to which the through travel lanes will be widened from the choices offered on the drop-down menu in the User Selection column. Only values greater than the existing lane width can be selected, up to a maximum lane width of 12 ft. • Shoulder Width: If the Shoulder Width box has been checked, select the width to which the shoulders will be widened from the choices offered on the drop-down menu in the User Selection column. Only values greater than the existing shoulder width can be selected, up to a maximum shoulder width of 8 ft. • Modify Proportion of Shoulder Width that is Paved: If the Modify Proportion of Shoulder Width that is Paved box has been checked, enter the modified paved shoulder proportion value in the User Selection box. Modified proportions that decrease the width of the shoulder that is paved cannot be entered. • Roadside Slope: If the Roadside Slope box has been checked, select the improved roadside slope from the drop-down menu in the User Selection column. Only slopes flatter than the existing roadside slope can be selected. The flattest slope that may be considered is 1V:6H. • Centerline Rumble Strip: If the Centerline Rumble Strip box has been checked, no further data entry is necessary. Installation of a centerline rumble strip along the entire length of the roadway section will be considered. Note that if a centerline rumble strip already exists on the roadway section, checking the Centerline Rumble Strip box will have no effect. In this case, the cost of installing the rumble strip after repaving will automatically be added to the project cost of the 3R project. This option is considered for four-lane undivided highways only. • Shoulder Rumble Strip: If the Shoulder Rumble Strip box has been checked, no further data entry is necessary. Installation of a shoulder rumble strip along the entire length of the outside shoulders on both sides of the roadway section (and the inside shoulders on divided roadways) will be considered. Note that if a shoulder rumble strip already exists on the road- way section, checking the Shoulder Rumble Strip box will have no effect. In this case, the cost of installing the rumble strip after repaving will automatically be added to the project cost of the 3R project. 0.8 Lane Width (ft) Retain Lane Width Shoulder Width (ft) Retain Shoulder Width Modify Proportion of Shoulder Width that is Paved 1 Roadside Slope Retain Roadside Slope Centerline Rumble Strip Retain Centerline Rumble Strip Shoulder Rumble Strip Not Selected Enhanced Striping/Delineation Not Selected Consider for Improvement Value Selected Alternatives to Consider User Selection Figure A-31. Data entry form to select alternatives to consider for rural four-lane highways.

User’s Guide for Spreadsheet Tool 1 157   • Enhanced Striping/Delineation: If the Enhanced Striping/Delineation box has been checked, installation of durable pavement markings will be considered for both centerline and edge striping. The data entry form shown in the screenshot in Figure A-32 will appear if this option is selected. Installation of roadside delineators will also be considered if the Total Length of Section with Delineator Posts field in Figure A-32 is set to a value larger than zero. • Total Length of Section with Delineator Posts: Enter the length of the roadway section that will have roadside delineator posts in miles. Include both sides of the roadway separately (i.e., enter 2 mi if a 1-mi roadway section has roadside delineators on both sides of the roadway). Superelevation improvements to horizontal curves are selected for consideration not by checking a box in the data entry form shown in Figure A-31, but rather by selecting Yes in the Consider for Improvement column in the data entry form shown in Figure A-27 for horizontal curves whose superelevation potentially needs improvement. A2.4 Comments/Notes The R4UD_Project worksheet includes a Comments/Notes field into which the user can enter, and retain a record of, any project- or site-specific information that helps explain the issues being addressed with the tool. The information entered in the Comments/Notes field will be saved whenever the Tool 1 workbook as a whole is saved. A similar Comments/Notes field is included in the results section of the tool. A2.5 Analysis Results The results of the economic analysis are shown in the Results summary at the top of the R4UD_Project worksheet (see Figure A-33). Figure A-32. Enhanced Pavement Marking and Delineation Data for rural four-lane highways. Figure A-33. Results of benefit–cost analysis for rural four-lane highways.

158 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects The Results summary presents the following information: • PV Modified Total Cost: The implementation cost is estimated on the basis of typical or average conditions for a location without unusual project- or site-specific features that could affect the implementation cost. For example, the cost of superelevation restoration may vary from typical values according to whether adjustments to shoulders or embank- ments are needed. Where lane or shoulder widening occurs, the cost estimate assumes that all features outside the widened element need to be rebuilt. However, the cost estimate assumes that the portion of the existing lanes and shoulders not affected by the widening will be retained. – Calculated: The present value of the modified total project cost is shown in this cell. The modified total cost is the total project cost not including the cost of milling and resurfacing the existing traveled way. – User Supplied: Users can supply their own total project cost in this cell. Click the option button in this cell for the tool to use this user-supplied total cost in place of the value calculated by the tool. • Annual Safety Benefit: This is the calculated annual crash savings in dollars that is estimated to result from the selected 3R project roadway improvements (other than milling and resur- facing, which will be implemented whether or not the other improvements are made). • Present Value of Safety Benefit: This is the present value of the annual crash savings over the service life of the roadway improvements. • Benefit–Cost Ratio: The benefit–cost ratio is the ratio of the present value of safety benefit divided by the present value of the modified total cost. • Net Benefit: The net benefit is the present value of safety benefit minus the present value of the modified total cost. The annual number of crashes predicted before and after the 3R project, along with the annualized crash reductions (see Figure A-34), are shown to the right of the Results summary in the R4UD_Project worksheet. A2.6 View Calculations The user may access the R4UD_Calculations worksheet to review all of the intermediate values calculations in assessing the benefits and costs of the project. This is a read-only work- sheet that enables the user to review the calculations; it does not allow the user to change any results. Figure A-34. Crash frequencies before and after 3R project for rural four-lane highways.

User’s Guide for Spreadsheet Tool 1 159   A3 Rural and Urban Freeways This section presents the application of Tool 1 to candidate 3R projects on rural and urban freeways. These procedures can be applied to rural freeways with four, six, and eight through lanes and to urban freeways with four, six, eight, and 10 through lanes. The guidance addresses setup defaults (which can be either accepted unchanged or modified by the user), data entry for existing conditions on a specific roadway, specifying the alternative(s) to be considered, reviewing analysis results, and reviewing calculations. A3.1 Setup Defaults Before performing any benefit–cost analyses, first visit the FWY_Setup worksheet. The purpose of the FWY_Setup worksheet is to establish default values for assessment of 3R projects on freeways. The FWY_Setup worksheet contains default values for every non– site-specific data element needed by Tool 1 to perform the benefit–cost calculations. Thus, the user can perform analyses without changing any values in the FWY_Setup worksheet. However, the user has the option to modify any of the default values to other values that are consistent with the agency’s policies, practices, and experience. To change a default value, enter the modified value into the cell in the User Supplied column and click the option button in that cell. This user-supplied value will appear in the Values Used column as a replacement for the default value that was initially shown. Each of the data elements on the FWY_Setup worksheet is described in the following sections. A3.1.1 Road Elements Figure A-35 shows a screenshot of the road element defaults. Each item in the figure is discussed below. • Average Embankment Height: Average representation of the embankment height of the roadway cross section in feet for level, rolling, and mountainous terrain. The default values of average embankment height are based on estimates developed by Zegeer et al. (31). Figure A-35. Data entry form for road element defaults for freeways.

160 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects • Existing Base Depth: Depth in inches of base material underneath the traveled way and shoulder. • Milling Depth: Depth in inches to which flexible pavement of traveled way and shoulder will be milled as part of pavement resurfacing. This applies only to flexible pavement. • Pavement Depth: Depth in inches of flexible pavement for traveled way and shoulder. This applies only to flexible pavement. A3.1.2 Cost Elements The screenshots in Figure A-36 through Figure A-40 show the cost element defaults for freeways. Each element is discussed in detail below. All costs are in dollars. • Base Unit Cost: Cost of base material per cubic yard. • Milling Unit Cost: Cost of pavement milling per square yard. • Flexible Pavement Unit Cost: Material and installation cost of flexible pavement per cubic yard. • Rigid Pavement Unit Cost: Material and installation cost of rigid pavement per square yard. • Embankment Unit Cost: Cost of embankment material per cubic yard. • Right-of-way Unit Cost: Cost of acquiring right-of-way per acre for each freeway type. • Shoulder Rumble Strip Unit Cost: Cost per linear foot of installing a shoulder rumble strip. • Guardrail Unit Cost: Cost per linear foot of installing a W-shaped guardrail. • Cable Barrier Unit Cost: Cost per linear foot of installing a cable barrier. • Concrete Barrier Unit Cost: Cost per linear foot of installing a concrete barrier. • Guardrail Removal Unit Cost: Cost per linear foot of removing a guardrail. • Cable Barrier Removal Unit Cost: Cost per linear foot of removing a cable barrier. • Concrete Barrier Removal Unit Cost: Cost per linear foot of removing a concrete barrier. Figure A-36. Data entry form for cost element defaults for freeways, Part 1 of 5.

User’s Guide for Spreadsheet Tool 1 161   Figure A-37. Data entry form for cost element defaults for freeways, Part 2 of 5. Figure A-38. Data entry form for cost element defaults for freeways, Part 3 of 5.

Figure A-39. Data entry form for cost element defaults for freeways, Part 4 of 5. Figure A-40. Data entry form for cost element defaults for freeways, Part 5 of 5.

User’s Guide for Spreadsheet Tool 1 163   • Incidentals: Each incidental cost is calculated as a percentage of the project total cost, not including the right-of-way cost for each freeway type. – Signing and PM: Signing and pavement markings. • MARR/discount rate: Minimum attractive rate of return (MARR) for analysis of 3R project investments. Federal guidelines suggest an MARR value at 7%. The MARR value is also referred to as the “discount rate.” • Service Life: Expected useful life or service life in years for the roadway improvement. – Lane Widening: Service life for widening of the traveled way. – Shoulder Widening: Service life for widening of the shoulder adjacent to the traveled way. Note: Lane widening and shoulder widening should always be assigned identical service lives. – Rumble Strip Installation: Service life of centerline and shoulder rumble strips. – Guardrail Installation: Service life of guardrails. – Cable Barrier Installation: Service life of cable barriers. – Concrete Barrier Installation: Service life of concrete barriers. • Crash Cost by Severity: Societal crash costs by crash severity level. Crash severity levels are defined in a manner consistent with the HSM. – Fatal: Cost of a fatal crash. – Disabling Injury: Cost of a disabling injury crash. – Evident Injury: Cost of an evident injury crash. – Possible Injury: Cost of a possible injury crash. – Property Damage Only: Cost of a property-damage-only crash. A3.1.3 Safety Elements Figure A-41 shows a screenshot of the safety element defaults for freeways. The only safety defaults that can be modified for freeways are the calibration factors (see Figure A-41). • Calibration Factor: This is a factor to adjust crash frequency estimates produced from the safety prediction procedure to approximate local conditions. A default value of 1.0 is built into the tool. A3.2 Data Entry After the setup defaults have been either retained or modified, as the user wishes, the tool is ready to perform benefit–cost analyses for freeways. Proceed to the FWY_Project worksheet. Note: SDF = severity distribution function. Figure A-41. Data entry form for safety element defaults for freeways.

164 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects Use the FWY_Project worksheet to enter all existing roadway attributes and select roadway improvements to consider in the benefit–cost analysis. The following sections step through each input data entry form in the FWY_Project worksheet. A3.2.1 Roadway Data The screenshot in Figure A-42 shows the Roadway Data entry form for freeways. • Area Type: Select either Urban or Rural from the drop-down menu for the area in which the freeway resides. • Section Length: Length of the roadway section in miles. • AADT: Enter the annual average daily traffic volume in vehicles per day for two-way traffic on the roadway section. This typically represents the existing or current AADT for the roadway being analyzed. Where substantial future growth in AADT is expected, the average AADT over the anticipated project service life may be used. • Terrain: The terrain in which the roadway section is located. • Pavement Type: Type of pavement of the roadway section, which is either flexible or rigid. A3.2.2 Alignment Data The Alignment Data entry form shown in the screenshot in Figure  A-43 addresses the method that will be used to describe the horizontal curvature of the roadway section of interest. Use the option buttons in Figure A-43 to select either entry of average curve data or entry of specific curve data. Depending on which option button is selected, different data entry forms will appear on the worksheet. The following two figures show the data entry forms for average curve data (Figure A-44) and specific curve data (Figure A-45). Note that the user will only see the data entry form corresponding to the option that has been chosen for entering alignment data. • % of Section Length on Curves: Enter the percentage of the roadway section that is on horizontal curves. Include spiral transitions in the percentage if present. • Typical Curve Radius: Enter the average horizontal curve radius of the roadway section. Figure A-42. Roadway Data entry form for freeways. Figure A-43. Alignment Data entry option for freeways.

User’s Guide for Spreadsheet Tool 1 165   • Number of Curves on Section: Enter the number of horizontal curves on the roadway section for both roadways of the freeway. For example, if a freeway section has two horizontal curves in each direction of travel, then enter “4” in this cell. • Number of Curves in Roadway Section: Enter the total number of horizontal curves on the roadway section for both roadways of the freeway. For example, if a freeway section has two horizontal curves in each direction of travel, then enter “4” in this cell. A maximum of 10 curves can be entered in the Specific Curve Data form. If more than 10 curves need to be considered, the roadway section may be split into shorter sections for analysis. If there are no curves or the user does not wish to consider superelevation improvement as an option for the 3R project, then enter “0” for the number of curves. The user should enter the following data for each horizontal curve on the roadway section: • Curve Length in Segment: Enter the length in miles of the horizontal curve including spiral transitions. • Curve Radius: Enter the radius in feet of the horizontal curve. A3.2.3 Existing Cross Section Data Use the Existing Cross Section data entry form shown in the screenshot in Figure A-46 to define the following features of the roadway section: • Number of Through Lanes: Select the total number of through lanes on the freeway segment (including both directions of travel). • Lane Width: Select the existing lane width of the traveled way in feet from the drop-down menu. Figure A-44. Average Curve Data entry form for freeways. Figure A-45. Specific Curve Data entry form for freeways.

166 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects • Outside Shoulder Width: Select the existing outside shoulder width in feet from the drop- down menu. • Inside Shoulder Width: Select the existing inside shoulder width in feet from the drop-down menu. • Outside Roadside Slope: Select the existing roadside foreslope from the drop-down menu. • Median Width: Enter the median width, which is measured from the leftmost edge of the traveled way to the leftmost edge of the traveled way in the opposite direction, in feet. • Median Slope: Select the median cross slope from the drop-down menu. Select “Flat” if there is not a depressed median. • Median Barrier: Select the situation that best describes the presence of barriers in the median [for more detailed discussion of these options, see HSM Chapter 18 (3)]: – No Median Barrier: Absolutely no barriers exist in the median. – Continuous, Centered: A median barrier exists in the center of the median and runs the entire length of the freeway segment. – Continuous, Offset: A median barrier runs the entire length of the freeway segment, but is not centered in the median. – Discontinuous: Median barriers do exist on the freeway segment but are not continuous. • Outside Barrier: Select Yes from the drop-down menu if there are traffic barriers along the outside or right side of the freeway segment. Otherwise, if there are no outside barriers, select No. Outside barriers may include steel guardrail, concrete barriers, or cable barriers. • Clear Zone Width: Enter the width of the clear zone on the outside or right side of the freeway section in feet. • Inside Shoulder Rumble Strip: Select Yes from the drop-down menu if rumble strips exist on the inside shoulders of the roadway section. Otherwise, select No. • Outside Shoulder Rumble Strip: Select Yes from the drop-down menu if rumble strips exist on the outside shoulders of the roadway section. Otherwise, select No. • % of AADT during high-volume periods: Proportion of AADT during hours in which the traffic volume exceeds 1,000 vehicles per hour per lane. Figure A-46. Existing Cross Section data entry form for freeways.

User’s Guide for Spreadsheet Tool 1 167   A3.2.4 Median Barriers If Continuous, Centered; Continuous, Offset; or Discontinuous was selected from the Median Barrier drop-down menu in the Existing Cross Section data entry form (see Figure A-46), a Median Barrier data entry form will appear (see Figure A-47). Use this entry form to enter data about the median barrier, as explained below: • Number of discontinuous median barriers: Enter the total number of discontinuous (stand-alone) median barrier segments on the freeway segment. Ten is the maximum value. Do not count a continuous barrier in this number. • Cont. Med. Barrier Width: Enter the width in feet of the continuous median barrier. This option only appears for Continuous, Centered and Continuous, Offset median barriers. • W(near): Enter the distance in feet from the inside traveled way edge closest to the offset barrier to the barrier face. • Cont. Median Barrier Type: Select the continuous median barrier type from the drop-down menu. This option only appears for Continuous, Centered and Continuous, Offset median barriers. If discontinuous median barriers are present on the freeway segment, then a data entry form will appear (see Figure A-48). Use this data entry form to enter data about the discontinuous median barriers, as explained below: • Length of Inside Barrier: Enter the length in miles of the discontinuous median barrier. • Horizontal Clearance: Enter the distance in feet between the leftmost edge of the traveled way and the face of the discontinuous median barrier. • Barrier Type: Select the discontinuous median barrier type from the drop-down menu. A3.2.5 Outside Barriers If Yes was selected for the presence of outside barriers, the data entry forms shown in Figures A-49 and A-50 will appear. • Number of Outside Barriers: Enter the number of outside barriers present on the freeway segment. • Length of Outside Barrier: Enter the length in miles of the outside barrier. • Horizontal Clearance: Enter the distance in feet between the rightmost edge of the traveled way and the barrier face. • Barrier Type: Select the barrier type from the embedded drop-down menu. Figure A-47. Median Barrier data entry form for freeways. Figure A-48. Discontinuous median barrier data entry form for freeways.

168 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects A3.2.6 Crash History Option The user can choose to use the existing site-specific crash history of the roadway section to assist in calculating potential crash savings with the 3R project. Otherwise, the user can simply choose to retain the estimate given by the HSM crash prediction method. The choice between these options is made in the data entry form shown in Figure A-51. The advantage of using site-specific crash history is that the benefit estimate may better reflect local conditions. • Consider existing crash history?: Select Yes to use the site-specific crash history for the roadway section. Otherwise, select No. The Crash Data entry form shown in Figure A-52 will appear when Yes is selected for the consideration of existing crash history. • Crash History Period: Enter the number of years of available crash data. • Total MV-FI Crashes: Enter the total number of multiple-vehicle crashes on the roadway segment that fall into the following crash severity levels: – Fatal crash, – Disabling injury crash, – Evident injury crash, and – Possible injury crash. • Total MV-PDO Crashes: Enter the total number of multiple-vehicle crashes on the roadway segment that fall into the property-damage-only crash severity level. • Total SV-FI Crashes: Enter the total number of single-vehicle crashes on the roadway segment that fall into the following crash severity levels: – Fatal crash, – Disabling injury crash, – Evident injury crash, and – Possible injury crash. • Total SV-PDO Crashes: Enter the total number of single-vehicle crashes on the roadway segment that fall into the property-damage-only crash severity level. A3.3 Alternatives to Consider Near the bottom of the FWY_Project worksheet is a data entry form in which to specify which improvement alternatives should be considered in the benefit–cost analysis (Figure A-53). Check the checkboxes for alternatives to include in the analysis. Figure A-49. Outside Barrier data entry form for freeways. Figure A-50. Outside Barrier detailed data entry form for freeways.

User’s Guide for Spreadsheet Tool 1 169   Each alternative is described in more detail below. • Lane Width: If the Lane Width box has been checked, select the width to which the through travel lanes should be widened from the choices offered on the drop-down menu in the User Selection column. Only values greater than the existing lane width can be selected, up to a maximum lane width of 12 ft. • Outside Shoulder Width: If the Outside Shoulder Width box has been checked, select the width to which the outside shoulders should be widened from the choices offered on the drop-down menu in the User Selection column. Only values greater than the existing outside shoulder width can be selected, up to a maximum width of 12 ft. • Inside Shoulder Width: If the Inside Shoulder Width box has been checked, select the width to which the inside shoulders should be widened from the choices offered on the drop-down Figure A-51. Crash History option data entry form for freeways. Figure A-52. Crash Data entry form for freeways. Figure A-53. Data entry form to select alternatives to consider for freeways.

170 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects menu in the User Selection column. Only values greater than the existing inside shoulder width can be selected, up to a maximum width of 12 ft. • Median Barrier: If the Median Barrier box has been checked, select the details of the median barrier to be considered for adding (or modifying, in the case of existing discontinuous median barriers). See the following subsection on median barrier additions and modifica- tions for further explanation. • Outside Barrier: If the Outside Barrier box has been checked, the details of the outside barrier to be considered for adding (or modifying, in the case of existing outside barriers) will be specified in a later screen (see Section A3.3.1). • Inside Rumble Strip: If the Inside Rumble Strip box has been checked, no further data entry is necessary. Installation of a shoulder rumble strip along the entire length of the inside shoulders on both roadways will be considered. Note that if an inside rumble strip already exists on the roadway section, checking the inside rumble strip box will have no effect. In this case, the cost of installing the rumble strip after repaving will automatically be added to the project cost of the 3R project. • Outside Rumble Strip: If the Outside Rumble Strip box has been checked, no further data entry is necessary. Installation of a shoulder rumble strip along the entire length of the outside shoulders on both roadways will be considered. Note that if an outside rumble strip already exists on the roadway section, checking the outside rumble strip box will have no effect. In this case, the cost of installing the rumble strip after repaving will automatically be added to the project cost of the 3R project. A3.3.1 Adding and Modifying Median Barriers If the Median Barrier box on the data entry form shown in Figure A-53 has been checked, select the option from the drop-down menu that best suits the project being evaluated. Note that not all these options may be available, on the basis of existing median barriers present on the freeway section. • Install Continuous Centered Barrier: Select this option to install a continuous centered median barrier. This option will only appear when there is no existing continuous median barrier along the freeway. • Replace Offset with Centered Continuous Barrier: Select this option to replace an existing continuous offset median barrier with a continuous centered median barrier. This option will only appear when there is an existing continuous offset median barrier along the freeway. • Install Continuous Offset Barrier: Select this option to install a continuous offset median barrier. This option will only appear when there is no existing continuous median barrier along the freeway. • Only Add/Edit Discontinuous Barriers: Select this option to add and/or modify existing dis- continuous median barriers. This option will only appear if there is no existing continuous median barrier along the freeway. • Keep Continuous Barrier and Add/Edit Discontinuous Barriers: Select this option to keep the existing continuous median barrier and add or modify existing discontinuous median barriers. This option will only appear if there is an existing continuous median barrier. When the Median Barrier box is selected on the data entry form shown in Figure A-53, one or more data entry forms will appear below the entry form. First, go to the Median Barrier Changes data entry form (see Figure A-54). Depending on the option selected from the median barrier improvement/modification drop-down menu in the data entry form in Figure A-53, enter all necessary data in the Median Barrier Changes data entry form. • Number of discontinuous median barriers to add: Enter the total number of discontinuous (stand-alone) median barriers that will be added on the freeway segment. Ten is the maximum value. Do not count a continuous barrier in this number.

User’s Guide for Spreadsheet Tool 1 171   • Cont. Med. Barrier Width: Enter the width in feet of the new continuous median barrier. This option only appears for Continuous, Centered and Continuous, Offset median barriers. • W(near): Enter the distance in feet from the inside traveled way edge closest to the offset barrier to the barrier face. • Cont. Median Barrier Type: Select the continuous median barrier type from the drop-down menu. This option only appears for Continuous, Centered and Continuous, Offset median barriers. If discontinuous median barriers currently exist on the freeway section, and the median barrier improvement/modification checkbox is checked in Figure A-53, the user has the opportunity to make modifications to the existing discontinuous median lengths in the data entry form that will appear (see Figure A-55). To modify the length of the discontinuous median barrier, select Yes from the drop-down menu in the Edit Length of Median Barrier column of the data entry form shown in Figure A-55. Enter the modified barrier length in the New Length of Median Barrier column. If the dis- continuous median barrier had to be moved due to lane or inside shoulder widening, Yes will appear in the Auto Moved column. The cost of moving barriers is incorporated in the project cost estimate. If the user has indicated that discontinuous median barriers will be added, the data entry form shown in Figure A-56 will open. Enter all necessary data in the form. • Length of Median Barrier: Enter the length in miles of the discontinuous median barrier. • Horizontal Clearance: Enter the distance in feet between the leftmost edge of the traveled way and the face of the discontinuous median barrier. • Barrier Type: Select the type of discontinuous median barrier to be installed from the drop-down menu. A3.3.2 Adding and Modifying Outside Barriers When the Outside Barrier checkbox is selected in the data entry form shown in Figure A-53, one or more data forms will appear below the form. First, go to the Outside Barrier data entry form (Figure A-57). Indicate the number of outside barriers that will be added to the freeway section (maximum of 10). If only existing outside barriers are to be modified, then enter “0” for this entry and move onto the next entry form below. Figure A-54. Median Barrier Changes data entry form for freeways. Figure A-55. Existing discontinuous median barrier modifications data entry form for freeways.

172 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects If outside barriers currently exist on the freeway section and the outside barrier improvement/ modification checkbox is selected in Figure A-53, the user has the opportunity to make modifi- cations to the existing outside barrier lengths. To modify the length of the outside barrier, select Yes from the embedded drop-down menu in the Edit Length of Outside Barrier column of the data entry form shown in Figure A-58. Enter the modified length in the New Length of Outside Barrier column. If the outside barrier had to be moved due to lane and/or outside shoulder widening, Yes will appear in the Auto Moved column. The cost of moving barriers will be incorporated in the project cost estimate. If the user has indicated that outside barriers will be added, all necessary data in the data entry form shown in Figure A-59 should be added. • Length of Outside Barrier: Enter the length in miles of the outside barrier. • Horizontal Clearance: Enter the distance in feet between the rightmost edge of the traveled way and the face of the barrier. • Barrier Type: Select the barrier type from the drop-down menu. A3.4 Comments/Notes The FWY_Project worksheet includes a Comments/Notes field into which the user can enter, and retain a record of, any project- or site-specific information that helps explain the issues being addressed with the tool. The information entered in the Comments/Notes field will be saved whenever the Tool 1 workbook as a whole is saved. A similar Comments/Notes field is included in the results section of the tool. A3.5 Analysis Results The results of the benefit–cost analysis are shown in the Results summary at the top of the FWY_Project worksheet (Figure A-60). Figure A-56. New discontinuous median barrier data entry form for freeways. Figure A-57. Outside Barrier additions data entry form for freeways. Figure A-58. Existing outside barrier modifications data entry form for freeways.

User’s Guide for Spreadsheet Tool 1 173   The Results summary presents the following information: • PV Modified Total Cost: The implementation cost is estimated on the basis of typical or average conditions for a location without unusual project- or site-specific features that could affect the implementation cost. For example, the cost of superelevation restoration may vary from typical values according to whether adjustments to shoulders or embank- ments are needed. Where lane or shoulder widening occurs, the cost estimate assumes that all features outside the widened element need to be rebuilt. However, the cost estimate assumes that the portion of the existing lanes and shoulders not affected by the widening will be retained. – Calculated: The present value of the modified total project cost is shown in this cell. The modified total cost is the total project cost, not including the cost of milling and resurfacing the existing traveled way. – User Supplied: Users can supply their own total project cost in this cell. Click the option button in this cell for the tool to use this user-supplied total cost in place of the value calculated by the tool. • Annual Safety Benefit: This is the calculated annual crash savings due to the selected 3R project roadway improvements (other than milling and resurfacing, which will be implemented whether or not the other improvements are made). • Present Value of Safety Benefit: This is the present value of the annual crash savings over the service life of the roadway improvements. • Benefit–Cost Ratio: The benefit–cost ratio is the ratio of the present value of safety benefit divided by present value of the modified total cost. • Net Benefit: The net benefit is the present value of safety benefit minus the present value of the modified total cost. The annual number of crashes predicted before and after the 3R project, along with the annualized crash reductions (Figure A-61), are shown to the right of the Results summary in the FWY_Project worksheet. Figure A-59. New outside barrier data entry form for freeways. Figure A-60. Results of benefit–cost analysis for freeways.

174 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects A3.6 View Calculations The user may access the FWY_Calculations worksheet to review all of the intermediate values calculations in assessing the benefits and costs of the project. This is a read-only work- sheet that enables the user to review the calculations but does not allow the user to change any results. A4 Horizontal Curve Realignment on a Rural Two-Lane Highway An improvement alternative involving horizontal curve realignment on a rural two-lane highway can be evaluated by using a procedure provided in a separate worksheet in Tool 1. This worksheet is selected by choosing the R2U_Curve_Realignment tab. The R2U_Curve_Realignment worksheet considers a single alternative for realignment of a single horizontal curve. The worksheet can, of course, be applied repetitively to multiple realignment alternatives or multiple horizontal curves. There is no comparable analysis capability in Tool 2 because the alternatives that could be considered for horizontal curve realignment are essentially infinite. A4.1 Horizontal Curve Realignment Description Figure A-62 shows the scenario considered in Tool 1 for a horizontal curve realignment situa- tion assumed for the R2U_Curve_Realignment worksheet. The analysis applies to a single curve whose dimensions before and after realignment need to be specified by the user. The existing horizontal curve (i.e., the condition before improvement) has dimensions that are characterized by the following variables: RE = horizontal curve radius for existing curve (ft), Δ = deflection angle for existing curve (degrees), and LE = length of existing curve (ft). Figure A-61. Crash frequencies before and after 3R project for freeways.

User’s Guide for Spreadsheet Tool 1 175   The values of RE and ΔE need to be specified by the user. The value of LE can be computed as follows: = × ∆ × π 180 (1)L R E E The existing curve is to be potentially realigned by using a larger radius (RI), specified by the user, to reduce crashes. The curve is assumed to connect the same tangents, so the deflection angle, Δ, does not change. The length of the improved or realigned curve (LI) can be computed as 180 (2)L R I I= × ∆ × π where RI = horizontal curve radius for improved or realigned curve (ft) and LI = length of improved or realigned curve (ft). LI must, by definition, be greater than LE because RI is greater than RE. The total length of realigned road that needs to be built can be determined from the dimensions of the improved or realigned road as = + × ×    2 100 (3)STL L L P I T Figure A-62. Definition of dimensions for the existing and improved horizontal curves.

176 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects where L = length of road to be rebuilt (ft), LST = superelevation transition length at either end of the improved or realigned curve (ft), and PT = percentage of superelevation transition located on the tangent. A4.2 Setup Defaults All of the setup defaults for rural two-lane highways discussed in Section A1.1 apply to horizontal curve realignment. The service life value specified for slope flattening, lane widening, and shoulder realignment is also applied to curve realignment. A4.3 Data Entry The following sections step through each input data entry form in the R2U_Curve_Realignment worksheet. Fields in which data need to be entered by the user are highlighted in yellow. A4.3.1 Roadway Data Roadway data for the candidate curve realignment site to be assessed are entered in the data entry form shown in the screenshot in Figure A-63. The roadway input data that need to be supplied by the user are as follows: • Pavement Type: Type of pavement of the roadway section, flexible or rigid. • Pavement Depth: Depth in inches of flexible pavement for the traveled way. This applies only to flexible pavement. • Base Depth: Depth in inches of base material underneath the traveled way. • Shoulder Depth: Depth in inches of flexible pavement for the shoulder. • Shoulder Base Depth: Depth in inches of base material underneath the shoulder. • AADT: Annual average daily traffic volume in vehicles per day for two-way traffic on the roadway section. This typically represents the existing or current AADT for the roadway being analyzed. Where substantial future AADT growth is expected, the average AADT over the anticipated project service life may be used. • Avg Lane Width: Select the existing average lane width on the traveled way in feet from the drop-down menu. • Avg Paved Shoulder Width: Select the existing average paved shoulder width in feet from the drop-down menu. Roadway Type Rural 2-Lane Un Number of Lanes 2 Number of Lanes 2 Pavement Type Rigid Avg Lane Width (ft) 12.0 ft Lane Width (ft) 12.0 ft Length of Roadway (ft) 1571 Avg Paved Shoulder Width (ft) 3.0 ft Avg Shoulder Width (ft - Paved) 3.0 ft Pavement Depth (in) (*) 5 in Avg Unpaved Shoulder Width (ft) 1.0 ft Avg Shoulder Width (ft - Unpaved) 1.0 ft Base Depth (in) 8 in Roadside Slope (ft:ft) 3:1 Roadside Slope (ft:ft) 3:1 Shoulder Depth (in) 5 in Terrain Level Shoulder Base Depth (in) 8 in Embankment Height 2.5 AADT (veh/day) 10000 * Pavement depth input is used in the calculation of "Flexible" pavement but not in calculation of "Rigid" pavement. ROADWAY DATA GLOBAL EXISTING ROADWAY IMPROVED ROADWAY Figure A-63. Roadway Data entry form for curve realignment on rural two-lane highways.

User’s Guide for Spreadsheet Tool 1 177   • Avg Unpaved Shoulder Width: Select the existing average unpaved shoulder width in feet from the drop-down menu. If both a nonzero paved shoulder width and a nonzero unpaved shoulder width are specified, the unpaved shoulder is located outside the paved shoulder. • Roadside Slope: Select the existing roadside foreslope from the drop-down menu. • Terrain: The terrain in which the roadway section is located. A4.3.2 Curve Data Curve data for the candidate curve realignment site to be assessed, including both the existing and improved conditions, are entered in the data entry form shown in Figure A-64. The data elements that need to be entered in the form are highlighted in yellow. The remaining data shown in the form are computed values. The input data for the existing curve that need to be supplied by the user are as follows: • Radius: Radius in feet of the existing horizontal curve (i.e., before improvement). • Deflection Angle: Deflection angle (change in heading between the tangent roadways on either side of the curve) in degrees. The deflection angle is unchanged from before to after the improvement. The input data for the improved or realigned curve that need to be supplied by the user are as follows: • Radius: Radius in feet of the improved or realigned horizontal curve (i.e., after improvement). • SE Transition Length: Length in feet of the superelevation transition at each end of the improved or realigned curve, including both runoff and runout lengths. • % on Tangent: Percentage of the superelevation transition length that is located on the tangent rather than the curve. A4.4 Results Figure A-65 shows the Results summary for the economic analysis of curve realignment that are computed and displayed on the R2U_Curve_Realignment worksheet. The Results summary presents the following information: • PV Modified Total Cost: The present value of the modified total project cost is shown in this cell. The modified total cost is the total project cost, not including the cost of milling and resurfacing the existing traveled way. • Present Value of Safety Benefit: The present value of the annual crash savings over the service life of the roadway improvements. CURVE DATA Existing Curve Improved Curve Radius ft 500 Radius ft 2000 Deflection Angle degrees 45 Deflection Angle degrees 45 Tangent ft 207 Tangent ft 828 Curve Length ft 393 Curve Length ft 1571 SE Transition Length ft 0 % on Tangent % 0% Figure A-64. Curve Data entry form for curve realignment on rural two-lane highways.

178 Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects • Benefit–Cost Ratio: The benefit–cost ratio is the ratio of the present value of safety benefit divided by the present value of the modified total cost. • Net Benefit: The net benefit is the present value of safety benefit minus the present value of the modified total cost. Sensitivity analyses with a range of horizontal curve realignment alternatives found that the benefit–cost ratios for such alternatives seldom equal or exceed 1.0. Thus, it is unlikely that horizontal curve realignment will be found to be cost-effective, except in unusual cases. A4.5 View Calculations The results of intermediate value calculations are shown in the R2U_Curve_Realignment worksheet rather than in a separate worksheet. These intermediate values are found in the following tables: Cost Estimates, Horizontal Curve CMF, and Safety Benefit Calculator. RESULTS PV Modified Cost $ 412,644.00 PV Safety Benefit $ 89,514.84 B/C Ratio 0.217 Net Benefit -$ 323,129.16 Figure A-65. Economic analysis results for proposed horizontal curve realignment.