Practices for Balancing Safety Investments in a Comprehensive Safety Program (2022)

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8 This chapter provides an overview of the literature review findings on various HSIP practices reported in both the published literature and online sources that relate to the scope of the synthesis. The literature includes pertinent information from 36 state HSIP manuals as well as additional state HSIP annual reports and FHWA guides related to state HSIP and roadway safety manage- ment programs. Appendix C provides a list of the resources included in the literature review and a summary of individual state DOT practices. The primary information contained in the literature review is based on the state HSIP manuals unless otherwise referenced as another source. This chapter is organized in three sections: project identification, project prioritization, and project evaluation. Each section summarizes current state DOT practices, highlighting differences between basic and advanced practices, quantitative and qualitative practices, and state and local road practices. The project identification section is broken down into three subsections that cor- respond to the three general approaches to roadway safety management: spot, systemic, and sys- tematic. Each subsection describes the quantitative and qualitative approaches state DOTs use to identify projects. The project prioritization and project evaluation sections follow slightly different organization due to overlapping methodologies among spot, systemic, and systematic approaches. For the purposes of the literature review, the term “local” represents roads that are not owned by the state DOT (e.g., roads and highways owned or operated by a county, city, or township agency). Project Identification This section summarizes state DOT practices in HSIP project identification for three approaches to safety management: spot, systemic, and systematic. For each approach, this section summa- rizes state DOT practices and notes differences with respect to quantitative and qualitative methods as well as differences on state and local roads. Appendix C provides further details on specific approaches state DOTs used in spot project identification and whether the approach applies to HSIP projects on state roads, local roads, or both. Spot Agencies typically follow the six-step roadway safety management process documented in the HSM when implementing a crash-based safety management approach (2). For project identifica- tion, many agencies employ the first three steps of this process: (a) network screening, (b) diagnosis, and (c) countermeasure selection. Based on a review of HSIP practices, state DOTs use a variety of safety performance measures for network screening. Of the 52 agencies included in the review of spot project identification approaches, all use some type of quantitative approach for identifying projects on the state or local C H A P T E R 2 Literature Review

Literature Review 9   system. The quantitative approaches range from traditional methods, such as crash frequency and crash rate, to more rigorous and contemporary methods from the HSM that account for regres- sion to the mean and traffic volume [e.g., level of service of safety (LOSS), excess predicted crashes, expected crashes, and excess expected crashes]. As shown in Figure 2, the most common safety performance measures are not based on safety performance functions (SPFs), including average crash frequency and crash rate. Less than one-third of state DOTs are using more rigorous SPF-based methods to identify potential spot locations. For those state DOTs that use SPF-based methods, some developed state-specific SPFs, whereas others calibrated existing SPFs to be used in network screening. FHWA provides a list of state SPF calibration and development efforts on the Crash Modification Factors (CMF) Clearinghouse (6). As shown in Figure 3, there is nearly an even split of agencies that use the same method or a different method to identify potential spot projects on state and local roads. Of the 52 agencies, 28 use the same method and 24 use a different method. Of the state DOTs that documented a different approach to identify projects on state and local roads, the differences were typically based on data availability. For example, more data-intensive methods (e.g., LOSS, excess pre- dicted, expected, and excess expected) would be used on state roads, and more basic methods [e.g., crash frequency, crash rate, and equivalent property damage only (EPDO)] would be used 16 36 0 5 10 15 20 25 30 35 40 SPF-based Not SPF-based 28 24 0 5 10 15 20 25 30 Same Spot Project Identification Methods for State and Local Roads Different Spot Project Identification Methods for State and Local Roads Figure 2. Summary of methods to identify spot projects on state and local roads. Figure 3. Difference in methods to identify spot projects on state and local roads.

10 Practices for Balancing Safety Investments in a Comprehensive Safety Program on local roads. Similar variations allow the more data-intensive methods to be used on any roads for which enough data are available, regardless of state/local designation. Many state DOTs supplement the quantitative approach with some type of qualitative approach to identify potential project locations. The qualitative approaches typically allow for other stakeholders to help identify potential project locations based on public or political inputs, police requests, or observations by district or regional staff. Based on these inputs and professional judgment, the state DOTs may add these sites to the list of spot locations for further investigation. Although some state DOTs do not provide documentation of the project identification process, those that do use either quantitative approaches or a combination of quantitative and qualitative approaches. None of the state DOTs reviewed in this report use only qualitative approaches for identifying spot projects. Once potential project locations are identified, all state DOTs use more in-depth investigations to diagnose the crash patterns and underlying crash contributing factors. Similar to network screening, the methods range from basic crash summaries and collision diagrams to the use of tests of proportions and multidisciplinary site investigation teams. As shown in Figure 4, the most common methods are crash summaries and multidisciplinary site investigation teams, followed by the use of collision diagrams and tests of proportions. Refer to the survey results in Chapter 3 for more on identifying potential countermeasures, including differences in spot and systemic practices and differences on state and local roads. With respect to countermeasure selection, state DOTs use the diagnosis results to select appro- priate countermeasures that are effective and feasible. Some state DOTs have an approved list of countermeasures and associated CMFs for HSIP projects. For those agencies with an approved countermeasure list, some allow countermeasures beyond the preapproved list with justification of countermeasure effectiveness. To justify countermeasure effectiveness, many require the use of CMFs from the CMF Clearinghouse (7). As shown in Figure 5, 44 agencies use CMFs to justify countermeasures, and just over half of the agencies provide a state-specific list of CMFs for use in the analysis. Relatively few state DOTs preapprove specific countermeasures, but all must meet the HSIP project eligibility requirements in accordance with 23 U.S.C. 148. Systemic Based on the review of available documentation, the majority of agencies include some type of systemic approach, and relatively few do not indicate a systemic approach, as shown in Table 1. 0 5 10 15 20 25 30 35 40 45 50 Crash Summaries Multidisciplinary Site Investigations Collision Diagrams Tests of Proportions 50 45 17 7 Figure 4. Summary of methods to diagnose spot locations.

Literature Review 11   Specifically, only five state DOTs do not specify a systemic method on the state system, and only six do not specify a systemic method on the local system. For those state DOTs that do have a documented systemic approach, most identify systemic projects through some combination of identifying focus crash types, facility types, and risk factors; screening and prioritizing candidate locations; and selecting low-cost systemic countermeasures. Although many state DOTs use an approach that is relatively consistent with the process docu- mented in FHWA’s Systemic Safety Project Selection Tool (3), there are several variations of sys- temic project identification. In general, the literature review identified four general categories of approaches for identifying systemic projects: application of in-house tools or methodology, application of FHWA’s Systemic Safety Project Selection Tool, application of a tool unspecified but similar to FHWA’s Systemic Safety Project Tool, and application of the U.S. Road Assessment Program (usRAP) methodology. For state roads, the most common approach is an in-house methodology, as shown in the following examples: • Kentucky divides HSIP projects into five categories [roadway departure, intersections, non- motorized, commercial motor vehicle (CMV), and other initiatives] and uses a tailored identification/prioritization methodology for each. For intersections, Kentucky identifies and prioritizes sites based on a list of attributes correlated with severe crash types. For road- way departure, Kentucky focuses on rural, two-lane, high-speed facilities, then uses the HSM 0 5 10 15 20 25 30 35 40 45 50 Use CMFs to Justify Countermeasures State-Specific List of CMFs Approved List of Countermeasures 44 26 9 Figure 5. Summary of methods to justify countermeasures. Method Number of State DOTs Applying Method for State Roads Number of State DOTs Applying Method for Local Roads In-house methodology 29 32 FHWA Systemic Safety Project Selection Tool 9 8 Unspecified but appears to be consistent with FHWA Systemic Safety Project Selection Tool 8 4 No apparent systemic program 5 6 usRAP 2 2 Not applicable* 0 1 Total** 53 53 *District of Columbia does not have local roads. **Alabama uses both an in-house method and usRAP. Table 1. Summary of state DOTs using systemic project identification methods.

12 Practices for Balancing Safety Investments in a Comprehensive Safety Program methodologies to prioritize route segments based on predicted safety performance, and finally implements targeted improvements while minimizing right-of-way (ROW) and utility conflicts. • Nebraska created a Strategic Safety Infrastructure Projects Team (SSIPT) to identify systemic safety projects that can be implemented on a statewide basis, such as shoulder and centerline rumble strip projects and projects to remove obsolete guardrail. • Washington uses a custom approach for local roads where projects are identified through a local road safety plan (LRSP). The approach identifies and prioritizes projects based on the top crash type(s) in the local jurisdiction. Projects can be at intersections, spot or midblock locations, and corridors. • Wyoming implements systemic improvements that represent corridor, area, or statewide treatments that are generally low cost, and the application is not exclusive to spot locations. The data-driven application of systemic treatments considers the overall statewide crash reduction based on expected widespread deployment. In addition to quantitative approaches, some state DOTs use other resources, such as road safety audits, information obtained from the public, law enforcement agencies, and safety com- ponent reviews of other projects, to identify systemic projects. Appendix C provides further details on systemic project identification approaches based on the literature review and whether the approach applies to HSIP projects on state roads, local roads, or both. Refer to the survey results in Chapter 3 for more on identifying systemic project locations, including differences on state and local roads. In general, it was difficult to discern from the literature if there are differences in countermeasure selection practices for spot and systemic projects. As such, the results shown in Figure 5 for spot projects generally apply to systemic projects as well. For systemic countermeasure selection, some state DOTs, including Michigan, Oregon, and Texas, develop a list of preapproved counter- measures for systemic projects. Other state DOTs require a detailed analysis, similar to spot projects, to diagnose the systemwide crashes and select targeted countermeasures to address the underlying risk factors. For example, New Jersey conducts a risk assessment of locations across the network to select appropriate countermeasures and requires benefit-cost analysis to justify the selected countermeasure(s). Pennsylvania identifies promising cost-effective strategies and then identifies sets of locations where it is cost-effective to apply the strategies. Refer to the survey results in Chapter 3 for more on selecting potential countermeasures, including dif- ferences in spot and systemic practices and differences on state and local roads. Systematic Based on the review of available documentation, a limited number of state HSIP manuals include a documented systematic approach and provide guidance on how to identify systematic projects (see Table 2). The most common method of identifying a systematic project is to select a proven State Documented Systematic Approach for State Roads Documented Systematic Approach for Local Roads California Florida Idaho Kentucky Maine Michigan Pennsylvania � � � � � � � � � � � Table 2. Summary of state DOTs with documented systematic project identification methods.

Literature Review 13   countermeasure and then apply it to all eligible locations based on the roadway characteristics but not necessarily on a systemic risk-based analysis (e.g., paving unpaved shoulders, installing median barrier on divided highways that currently do not have a median barrier, or installing shoulder rumble strips on all rural roads with paved shoulders greater than 5 ft). As a result, the project identification process does not include any formal analysis for most state DOTs. There are, how- ever, some state DOTs using quantitative analysis as part of systematic project identification. For instance, Florida suggests the use of network screening results to help identify potential locations and common issues that could be addressed through systematic countermeasures. Pennsylvania determines the number of locations where the countermeasure can be deployed cost-effectively by setting a minimum threshold for the number of target crashes per location to achieve a desired benefit-cost ratio. Project Prioritization and Funding Allocation Based on the review of HSIP manuals and reports, state DOTs use a variety of measures, indices, and factors to prioritize projects and allocate funding. The following sections provide a brief overview, and Appendix C provides further details. Project Prioritization Methods Figure 6 provides a summary of the general approaches state DOTs use to prioritize projects, indicating which state DOTs apply the same prioritization method to all projects and which ones apply different prioritization methods for state and local projects or for spot, systemic, and systematic projects. Based on the documentation, the majority of state DOTs (33 of 52) use the same prioritization approach for all projects, 11 use a different approach for state and local projects, and five use a different approach for spot and systemic projects. State DOTs use a variety of approaches for project prioritization that include quantitative and qualitative factors. As shown in Table 3, ranking by benefit-cost ratio based on estimated reduc- tions in total crashes is the most common method (32 state DOTs). Some state DOTs use specific variations of the benefit-cost ratio to focus on specific crash severities. For instance, Arizona uses a benefit-cost ratio based on reductions in fatal and serious injury crashes for project prioritization. 33 11 5 3 0 5 10 15 20 25 30 35 Same approach applied to all projects Different approach for state and local projects Different approach for spot and systemic projects Not identified Figure 6. Summary of project prioritization approaches.

14 Practices for Balancing Safety Investments in a Comprehensive Safety Program Florida uses net present value when it is desired to select projects with higher benefits than the one with the greatest benefit-cost ratio. Florida also uses net present value in combination with benefit- cost ratio to select an eligible alternative that meets the needs of all stakeholders while still advancing the goals of the HSIP. In addition to using benefit-cost ratio or crash reduction as the primary ranking factor, many state DOTs consider other factors such as funding equity, alignment with program goals, and ease of implementation. Some state DOTs develop a weighted average index that accounts for benefit-cost ratio and other factors listed in Table 3. Those state DOTs prioritize projects by applying a standard scoring scheme and summing the results as an index. Funding Allocation Methods As shown in Table 4, 24 state DOTs prioritize all candidate projects together (i.e., no apparent funding split), whereas other state DOTs have set-aside funding or a specific program for certain types of projects. For those state DOTs with funding splits, the most common set-asides are for specific initiatives (14 state DOTs) and spot or systemic projects (12 state DOTs). Other set-aside practices included separate funds for state and local projects (three state DOTs) and Factors Number of State DOTs State DOTs Benefit-cost analysis 32 Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, District of Columbia, Florida, Georgia, Idaho, Illinois, Iowa, Louisiana, Minnesota, Montana, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, South Dakota, Texas, Utah, Vermont, Virginia, Washington, West Virginia Project cost and available funding 12 Alaska, Colorado, Connecticut, Massachusetts, Montana, Ohio, Pennsylvania, South Carolina, South Dakota, Vermont, Virginia, Wisconsin Ease of project delivery and schedule 10 Alabama, Alaska, Colorado, Florida, Maine, Nebraska, New Hampshire, Pennsylvania, Vermont, Virginia Crash or crash severity potential 7 Alabama, District of Columbia, Louisiana, Minnesota, Ohio, Pennsylvania, Virginia Alignment with program goals or focus areas 6 Alabama, Arizona, District of Columbia, Louisiana, Minnesota, Nebraska Engineering review 4 Alaska, Oregon, Vermont, Virginia Other impacts (e.g., ROW, environmental, operational, utilities) 4 Florida, Maryland, Massachusetts, Nebraska Project coverage and funding equity 3 Florida, Michigan, Minnesota Public requests, public acceptance, and political influence 3 Florida, Maryland, Vermont Coordination with other planned projects 2 Florida, Michigan Familiarity with countermeasure (design, construction, and safety effects) 2 Arizona, Florida Holistic effectiveness (4 E’s of safety [engineering, education, enforcement, and emergency medical services]) 1 Arizona Combined score (including multiple factors from above) 7 Alabama, Louisiana, Maryland, Minnesota, Ohio, Pennsylvania, Virginia Table 3. Summary of state DOT project prioritization methods.

Literature Review 15   separate funds for districts (two state DOTs). Note that the numbers in the table sum to more than 52 because some state DOTs use multiple set-aside methods. Although some state DOTs split funding between spot and systemic projects or state and local projects, few of the reviewed state DOTs have a formula to allocate funding between these projects. Instead of using a specific formula, some state DOTs have established goals for allocating HSIP funding to specific groups of projects (e.g., state/local or spot/systemic). The following is a summary of state HSIP funding allocation goals: • Alabama: Alabama allocates 50% of its federal HSIP funding to systemic projects and 30% to spot projects. For the remaining funds, Alabama allocates 7.5% to safety studies, 5.0% to safety research and data collection, 3.0% to enhanced enforcement activities, 2.5% to safety outreach programs, and 2.0% to miscellaneous programs and projects. Alabama may adjust the alloca- tions depending on the various needs and types of project requests from project sponsors. • Arizona: Arizona selects projects on the same funding level, with priority given to projects with the highest benefit-cost ratio. The state DOT allocates no more than 20% of HSIP funding to systemic projects unless special circumstances dictate otherwise. • California: California established the state-funded Systemic Safety Analysis Report Program (SSARP) in 2016. In October 2015, Caltrans set aside $10 million in HSIP funds for SSARP (8). Local agencies can submit applications for reactive (spot) projects based on benefit-cost ratio or for proactive (systemic) projects based on funding set-asides. The funding set-asides are for low-cost proactive countermeasures on local roads. The set-aside funding is generally 25% of the local HSIP funding, and the amounts are determined based on feedback from the Local HSIP Advisory Committee and previous HSIP cycle applications. In more recent funding cycles, the set-aside amounts increased for local systemic projects, as shown in Figure 7. This was due to the demand for those funds and a recognition of the importance of investing in proven counter- measures (9). • Indiana: The program goal for the Indiana DOT safety program is to obligate approximately 50% of available HSIP funds to systemic improvements annually. Actual obligations for sys- temic projects vary year to year due to project production factors and diversion of projects for obligation under the Section 164-HE Penalty Transfer. Indiana also allocates one-third of the total annual apportionment of HSIP funding to local public agencies for safety projects on local public roads. An annual apportionment of obligation authority is assigned to each metropoli- tan planning organization (MPO) serving Group 1 and Group 2 urban areas. A standardized population formula is used to determine allocation of all federal-aid funding made available to individual MPOs. For public agencies in rural areas, Group 3 (incorporated cities and towns) and rural Group 4 (counties and unincorporated towns), a predetermined amount of HSIP funds are made available for eligible projects. The population formula is also used to determine the total amount of the HSIP allotted for projects located in rural areas (10). Methods State DOTs No apparent funding splits 24 Separate funds for specific initiatives 14 Separate funds for spot and systemic projects 12 Separate funds for state and local projects 3 Separate funds for each district 2 Not identified 3 Total 52 Table 4. Summary of state DOT funding allocation methods.

16 Practices for Balancing Safety Investments in a Comprehensive Safety Program • Iowa: Iowa creates a $2 million set-aside of HSIP funds each fiscal year for the HSIP Secondary Program, which replaces the historic High-Risk Rural Roads (HRRR) Program. • Kentucky: Kentucky HSIP projects are divided into five categories: roadway departure, inter- sections, nonmotorized, CMV, and other initiatives. Figure 8 shows the distribution of HSIP funding among all initiatives (11). • Michigan: Michigan has focused HSIP expenditures on spot improvements with an annual average distribution of approximately 40% to 50% for systemic improvements between FY 2014 and 2018 (Figure 9). However, this distribution varies significantly between state and local routes. HSIP expenditures on state routes have focused primarily on systemic improve- ments with an annual average of approximately 54%, whereas HSIP expenditures on local routes have focused on spot improvements with an annual average of approximately 85% (12). Michigan set HSIP funding allocation goals for FY 2021 at 45% for spot projects and 55% for systemic projects. • Minnesota: For HSIP projects, Minnesota balances HSIP funds among spot and systemic projects by focusing on a mix of risk mitigation and historical crash consideration. Beyond the HSIP, Minnesota supports a district safety set-aside to ensure that priority safety items outside the HSIP have an opportunity to be funded. Practices vary among the districts regarding non-HSIP safety set-aside funds to implement improvements. • Missouri: Missouri distributes HSIP funds to each of the seven districts based on a 3-year average of the number of fatalities and serious injuries in each area. • New Jersey: New Jersey has set annual HSIP funding allocation goals based on Strategic Highway Safety Plan (SHSP) emphasis areas and the distribution of fatal and serious injury crashes among state and local jurisdictions. The funding split is approximately 40% on state roads and 60% on county and municipal roads, which aligns with the current distribution of serious injuries and fatalities. • North Carolina: North Carolina divided HSIP funding among three target crash types in 2020: roadway departure crashes (50%), intersection crashes (35%), and pedestrian and bike crashes (15%). Within each target crash type, North Carolina further apportioned HSIP funding between spot and systemic projects. Systemic projects received 80%, 40%, and 40% of allocated funding for the roadway departure program, intersection program, and pedes- trian and bike program, respectively. • Oregon: Within regions, total funding is divided equally between the spot and systemic com- ponents. Within the systemic component, Oregon recommends that regions split funding Source: California Department of Transportation (9). $0 $50 $100 $150 $200 $250 M ill io ns HSIP Cycle BCR Set-Aside 81% 19% $220 10 81% 19% $184 9 89% 11% $209 8 100% $160 7 Figure 7. California local HSIP set-aside and benefit-cost ratio funding.

Literature Review 17   Source: Kentucky Department of Transportation (11). Signs, $1,000,000 FD05 Shoulders, $3,500,000 Systemic Intersection Improvements, $1,000,000 Intersection Emphasis, $6,000,000 Non-Motorized, $250,000 Commercial Motor Vehicle, $250,000 Safety Circuit Rider, $150,000 KTC Technical Assistance, $175,000Preconstruction Funding KYTC Personnel, $300,000 Localized Risk Mitigation Projects, $6,021,080 Cable Barrier, $2,500,000 High Friction Surface, $500,000 FE06 Match, $750,000 National Highway System Guardrail/End Terminals, $750,000 Roadway Departure Corridors, $18,000,000 Source: Michigan Department of Transportation (12). Figure 8. Kentucky investments by initiative. Figure 9. Michigan HSIP project expenditures by site selection method.

18 Practices for Balancing Safety Investments in a Comprehensive Safety Program between the emphasis areas identified in the Transportation Safety Action Plan (TSAP) based on the proportion of the fatal and serious injury crashes occurring within those categories within the previous 5 years. The current emphasis areas are roadway departure, intersection, and bike/pedestrian. • Pennsylvania: Each year, Pennsylvania receives approximately $97 million in HSIP funding. The department distributes $45.5 million of this funding to its planning regions based on fatalities, major injuries, and reportable crashes. Each planning organization receives $500,000 to allow for larger projects in the smaller planning organizations. The remaining $35 million is awarded annually to implement low- to moderate-cost systemic infrastructure safety improvements. Thus, approximately 36% of total federal HSIP funds are used for systemic improvements. • Rhode Island: Rhode Island plans to split funding 90/10 for systemic and spot projects, respectively. • South Carolina: South Carolina allocates HSIP funding based on the SHSP crash categories and emphasis areas. The funding for these emphasis areas is as follows, with some overlap between categories: roadway departure ($20 million), Interstate Safety Program ($11 million), Rumble Strip Program ($9 million), intersections and other high-risk locations ($18 million), Intersection Safety Program ($13 million), Road Safety Assessments Program ($5 million), and nonmotorized users ($5 million). • Texas: Texas allocates 40% of HSIP funding to systemic projects, of which 62.5% is for district systemic projects and 37.5% is for systemic projects on the state system. • Vermont: Vermont allocates 60% of HSIP funding for spot projects and 40% for systemic improvements. Project Evaluation Evaluations help to assess the effectiveness of the HSIP. Project-level evaluations help to explain whether an individual effort or investment was successful at correcting or addressing the crash contributing factors at a given location. Countermeasure-level evaluations are useful to estimate CMFs and inform future investment decisions. Program-level evaluations reveal the effectiveness of the HSIP or subprograms in reaching established goals and reducing the number of fatal and serious injury crashes. This section focuses on state DOT practices for project-level and countermeasure-level evaluations. It does not separate practices by state and local roads or spot and systemic approach, because these differences are not readily apparent in the literature. Refer to the Chapter 3 survey results for further details on differences in evaluation methods by facility type (state and local roads) and approach (spot and systemic). Based on the review of HSIP manuals and annual reports, HSIP evaluation methods vary by state DOTs in terms of both breadth and depth of analysis. Within a state DOT, the evaluation method appears to be the same for all projects regardless of how the projects were identified or prioritized (e.g., identified by spot, systemic, or systematic approaches or implemented on a state or local road). Evaluation methodologies are primarily quantitative in nature and range in the rigor of analysis. Some state DOTs use methods that differ in rigor within the HSIP. For instance, North Carolina uses simple before–after methods to evaluate spot projects but uses a more rigorous method for evaluating systemic projects. This is primarily due to the fact that systemic projects are more similar to countermeasure-level evaluations and include multiple treated locations, in which case North Carolina uses more reliable before–after methods. The most common approach to evaluating the safety effectiveness of HSIP projects is the simple before–after study design without traffic volume correction. Relatively few state DOTs use anything more rigorous, such as before–after with traffic volume correction, shift of

Literature Review 19   proportions, empirical Bayes (EB) before–after study design, or experimental before–after study design, as shown in Table 5. State DOT guidance on HSIP project evaluations can range from detailed evaluation procedures to acknowledgment of an evaluation process to no reference of evaluations at all. Appendix C provides summaries of the evaluation methods by state DOT, as identified in state HSIP guidance and reports. Chapter Summary This chapter summarized state HSIP practices for identifying, prioritizing, and evaluating spot, systemic, and systematic projects on state and local roads. The literature review included HSIP manuals from 36 state DOTs as the primary source of information. HSIP annual reports and select national HSIP guides and resources served as supplemental sources of information. The process to identify, prioritize, and evaluate spot projects is fairly well established, as evidenced by the documentation in most state DOTs, but there are fewer state DOTs with a documented systemic or systematic approach. Project Identification Although the traditional quantitative performance measures for network screening (e.g., crash frequency and crash rate) are most common for spot projects, there are several state DOTs that have implemented more rigorous and contemporary methods from the HSM (e.g., LOSS, excess predicted, expected, and excess expected crashes). Once potential project loca- tions are identified, nearly all state DOTs use more in-depth investigations to diagnose the crash patterns and underlying crash contributing factors. The diagnostic methods for spot locations range from basic crash summaries and collision diagrams to the tests of proportions and multidisciplinary site investigation teams. The diagnosis results typically inform counter- measure selection, but some state DOTs provide further guidance, including an approved list of countermeasures and a list of CMFs. Based on the review, approximately 75% of agencies include some variation of the systemic approach in the HSIP manual, and nearly 90% include some mention of a systemic approach in the HSIP manual or annual report. The methods range from basic to advanced, with the majority of state DOTs using more basic approaches to systemic analysis. For systemic countermeasure Evaluation Method State DOTs Simple before–after study Alabama, Alaska, Arizona, Arkansas, California, Colorado, Georgia, Idaho, Illinois, Iowa, Louisiana, Maine, Massachusetts, Minnesota, Mississippi, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Puerto Rico, Rhode Island, South Carolina, Tennessee, Texas, Utah, West Virginia, Wyoming Before–after with EB adjustment Florida, North Carolina, Rhode Island, Tennessee, Virginia Shift of proportions Florida, Kentucky, Mississippi Before–after study with traffic volume correction Florida, Vermont Experimental before–after study Number of State DOTs 32 5 3 2 1 Minnesota Table 5. Summary of state DOT project evaluation methods.

20 Practices for Balancing Safety Investments in a Comprehensive Safety Program selection, several state DOTs select from a list of preapproved countermeasures. There are several variations of systemic approaches in practice, including the following: • In-house tools or methodology (32 state DOTs) • FHWA Systemic Safety Project Selection Tool or similar (18 state DOTs) • usRAP methodology (two state DOTs) For both spot and systemic approaches, most state DOTs use the same method to identify potential projects on state and local roads. Of the state DOTs that use a different approach, the justification is typically related to data availability (e.g., using more reliable methods as data allow). Also, many state DOTs supplement the quantitative spot and systemic approaches with qualitative input from stakeholders (e.g., public inputs, police requests, or observations by dis- trict or regional staff) to help identify potential project locations. A limited number of state HSIP manuals include a documented approach and guidance on how to identify systematic projects. The most common method is to select a proven countermeasure and then apply it to all eligible locations. As a result, most systematic project identification pro- cesses do not include any formal analysis. Some state DOTs do use quantitative analysis as part of systematic project identification to justify the widespread application of countermeasures. Project Prioritization State DOTs use a variety of measures, indices, and factors to prioritize projects. The most common quantitative approach to project prioritization is the benefit-cost ratio. Most state DOTs that compute the benefit-cost ratio base the estimate on expected reductions in total crashes; however, some state DOTs use variations, such as benefits based on expected reductions in fatal and serious injury crashes. Many state DOTs also incorporate one or more non-crash-based factors, such as funding equity, alignment with program goals, and ease of implementation. Funding Allocation Some state DOTs prioritize all candidate projects together, and some have set-aside funding for state and local projects, spot and systemic projects, or specific emphasis areas (e.g., roadway departure, intersection, pedestrian, bicycle). Although some state DOTs split funding between spot and systemic projects or state and local projects, few of the reviewed state DOTs have a formula to allocate funding between these projects. The most common quantitative approaches to allocating funding are based on the distribution of fatal and serious injury crashes. Other state DOTs have established funding allocation goals based on qualitative assessments and profes- sional judgment. Project Evaluation Project evaluation methods vary by state DOT in terms of both breadth and depth of analysis. The simple before–after study design without traffic volume correction is the most common project evaluation method. Relatively few state DOTs use anything more rigorous, and state DOT guidance on project evaluations ranges from detailed procedures to acknowledgment of an evaluation process to no reference of evaluations at all. Some state DOTs use more reliable methods to develop CMFs based on countermeasure-level evaluations.