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From page 38... ... HFG TUTORIALS VERSION 2.1 22-1 CHAPTER 22 TUTORIALS TUTORIALS FROM NCHRP REPORT 600: HUMAN FACTORS GUIDELINES FOR ROAD SYSTEMS Tutorial 1: Real-World Driver Behavior Versus Design Models...……………………….……22-2 Tutorial 2: Diagnosing Sight Distance Problems and Other Design Deficiencies.…………….22-9 Tutorial 3: Detailed Task Analysis of Curve Driving.………………………………………...22-35 Tutorial 4: Determining Appropriate Clearance Intervals…………………………………….22-38 Tutorial 5: Determining Appropriate Sign Placement and Letter Height Requirements...…...22-39 Tutorial 6: Calculating Appropriate CMS Message Length under Varying Conditions...……22-43 NEW TUTORIALS Tutorial 7: Joint Use of the Highway Safety Manual (HSM) and the Human Factors Guidelines for Road Systems (HFG) Read the entire page →
From page 39... ... Tutorial 1: Real-World Driver Behavior Versus Design Models Much of the information on sight distance presented in Chapter 5 reflects the application of empirically derived models to determine sight distance requirements. Such models, while valuable for estimating driver behavior across a broad range of drivers, conditions, and situations, have limitations. Read the entire page →
From page 40... ... This model shows that the sight distance requirement is composed of (at least) two distances: there is a distance traveled while the driver perceives and evaluates a situation (determined by PRT and vehicle speed) Read the entire page →
From page 41... ... Conditions or Events that Occur Prior to a Hazardous Event/Object Becoming Visible to the Driver The model shown in Figure 22-1 is not sensitive to events that happen prior to the moment that the hazardous object or event becomes visible to the driver. In reality, the driver's ability to react to a hazardous object or event may be strongly influenced by previously occurring conditions or events. Read the entire page →
From page 42... ... The basic sight distance behavioral model (Figure 22-1) makes assumptions about driver cognitive state and speed choice as the hazardous event is encountered. Read the entire page →
From page 43... ... is generally reasonable from a design perspective, however, because it is somewhat conservative. Specifically, those drivers who encounter a situation without planning or anticipation are those most likely to be in need of the full sight distance requirement. Read the entire page →
From page 44... ... distance, driver/vehicle capabilities) determines options and shapes the way drivers respond, and often multiple options are available to the driver. Read the entire page →
From page 45... ... ical observations made at the site may be at variance with the predicted behaviors. Even when design equations are based on "good" data, the generality of the models suggests that credence should be given to any empirical data that can be collected at the site itself. Read the entire page →
From page 46... ... Tutorial 2: Diagnosing Sight Distance Problems and Other Design Deficiencies Introduction The previous sections of this document -- especially Chapter 5 -- have provided design guidelines for human factors aspects of various sight distance concepts. However, for users to implement these guidelines in a practical sense, it is desirable to provide a procedure for their operational application. Read the entire page →
From page 47... ... H FG T U TO RIA LS Version 2.0 22-10 Figure 22-3. Flow diagram of six-step diagnostic process. Read the entire page →
From page 48... ... 22-11 HFG TUTORIALS Version 2.0 Step 1A: Identify Hazard and Prepare Site Diagram The specific hazard location under investigation is identified and the approach roadway is diagrammed. Example of hazards requiring sight distance consideration and the associated sight distance concepts are as follows. Read the entire page →
From page 49... ... HFG TUTORIALS Version 2.0 22-12 Step 1C: Observe Erratic Vehicle Maneuvers on Approach Observations of vehicle movements should be considered in situations of sufficiently high traffic volumes to justify this type of study, e.g., 100 vehicles per hour (vph) and above. Read the entire page →
From page 50... ... 22-13 HFG TUTORIALS Version 2.0 Step 1F: Note Factors Affecting Flow Speeds Certain roadway environmental features are known to affect drivers' selection of speed. Examples are pavement defects, narrow shoulder widths and protruding bridge piers, abutments, guardrails, median barriers, etc. Read the entire page →
From page 51... ... HFG TUTORIALS Version 2.0 22-14 Step 1I: Label the Diagram with Specified Symbols SDHAZ -- Sight distance to a potential hazard. The point at which a location or object is first detectable to an approaching motorist. Read the entire page →
From page 52... ... 22-15 HFG TUTORIALS Version 2.0 Step 2: Conduct Preliminary Engineering Analyses This step involves the application of traditional traffic engineering techniques (e.g., AASHTO Design Policy geometric design criteria and DSD warrant) as a preliminary determinant of site deficiencies. Read the entire page →
From page 53... ... HFG TUTORIALS Version 2.0 22-16 Step 2D: Examine Approach with respect to DSD Warrants The approach to the hazard location also must be examined for conditions of visual clutter meeting requirements for DSD application. In particular, these conditions could take the form of roadside distractions and/or complex TCDs at intersections along the approach. Read the entire page →
From page 54... ... 22-17 HFG TUTORIALS Version 2.0 Step 3: Apply Crash Data This step involves the integration of traffic crash data into the analysis. The objective is to locate specific crash-prone locations within the roadway segment, which may be indicative of sight distance problems. Read the entire page →
From page 55... ... HFG TUTORIALS Version 2.0 22-18 Step 3C: Examine Potential Sight Distance Causation Effect Certain patterns of crash behaviors (i.e., pre-collision maneuvers) are suggestive of sight distance problems: for example, single-vehicle or run-off-road crashes with a fixed object that may appear visible under some conditions but may not be easily detectable to drivers during conditions of more limited visibility (e.g., darkness) Read the entire page →
From page 56... ... 22-19 HFG TUTORIALS Version 2.0 Step 4A: Establish and Plot Action Points Along Approach Segment Specific locations within the study roadway section requiring a driver action (e.g., maneuver) will be identified and plotted. Read the entire page →
From page 57... ... HFG TUTORIALS Version 2.0 22-20 Step 4B: Establish and Plot Information Sources and Associated Sight Distances Along Approach Segment Any driver action (e.g., hazard avoidance) must be based on information available to the driver. Read the entire page →
From page 58... ... 22-21 HFG TUTORIALS Version 2.0 Step 4C: Define Component Driver Response Sections Within Approach Segment Distinctly different driver informationprocessing tasks are associated with each detection and maneuver activity. In this step, roadway sections will be designated and plotted to illustrate the required travel distances over which the driver would perform these varied information-processing and maneuver tasks. Read the entire page →
From page 59... ... HFG TUTORIALS Version 2.0 22-22 Step 5A: Determine the Relevant Geometric Design Sight Distance Application The analysis of driving task requirements involves application of the appropriate sight distance value for the given task. Sight distance requirements (to accommodate both the information-processing and maneuver tasks) Read the entire page →
From page 60... ... Step 5B: Determine Driving Task Requirements Within Each Component Roadway Segment Case 1: Direct line of sight to hazard; no traffic control SDHAZ ➞ A In this case, PRT and MT are determined from Section 5.2. Case 2: Intervening traffic control device (i.e., warning of hazard) Read the entire page →
From page 61... ... HFG TUTORIALS Version 2.0 22-24 Step 5C: Quantify the Applicable PRT and MT Requirements for Each Driving Task Component No TCDs present: SDHAZ ➞ A Apply applicable PRT and MT requirement corresponding to predetermined condition (i.e., SSD, ISD, DSD, or PSD as determined in Step 5A) Read the entire page →
From page 62... ... 22-25 HFG TUTORIALS Version 2.0 Step 5D: Assess the Adequacy of the Available Sight Distance Components Case 1: Direct line of sight to hazard; no traffic control SDHAZ ➞ A Does the subsection length SDHAZ ➞ A allow sufficient time for the driver to perform any required hazard avoidance maneuver? Case 2: Intervening traffic control device (i.e., warning of hazard) Read the entire page →
From page 63... ... Step 6: Develop Engineering Strategies for Improvement of Sight Distance Deficiencies In this final step, the practitioner recommends improvement (e.g., traffic control device applications or minor design modifications) to correct deficiencies. Read the entire page →
From page 64... ... 22-27 HFG TUTORIALS Version 2.0 Example Application: Sight Distance Diagnostic Procedure The example driving situation consists of a 55-mi/h, two-lane rural roadway that approaches a 35-mi/h curve followed by a stop-controlled intersection. The intersection approach is to a main highway, which requires application of destination guide signing. Read the entire page →
From page 65... ... Signed Intersection Approach Segment Steps 2A through 2D: Examine Site with Respect to AASHTO Design and DSD Criteria. For the purpose of this example, it is assumed that geometrics conform to AASHTO and that DSD criteria (e.g., visually cluttered environmental conditions) Read the entire page →
From page 66... ... • Case 1, direct line of sight to hazard (i.e., 35-mi/h speed zone to intersection) : SDHAZ ➞ A • Case 2: Three intervening traffic control devices – A route shield assembly: SDTCD1 ➞ LDTCD1 ➞ TCD1 ➞ A – A destination name sign: SDTCD2 ➞ LDTCD2 ➞ TCD2 ➞ A – A stop sign: SDTCD3 ➞ LDTCD3 ➞ TCD3 ➞ A This roadway segment is diagrammed in Figure 22-7. Read the entire page →
From page 67... ... Step 5C: Quantify the Applicable PRT and MT Requirements for Each Driving Task • Case 1, direct line of sight to hazard (i.e., 55-mi/h speed zone to 35-mi/h curve) : SDHAZ ➞ A Because DSD does not apply (determined previously) Read the entire page →
From page 68... ... Step 5B: Determine the Driving Task Requirements. Considering the two possibilities (i.e., Case 1 in which the driver proceeds to the intersection ahead while ignoring the signs, and Case 2 whereby the driver observes and comprehends the intermediate signs) Read the entire page →
From page 69... ... The legibility distance of symbol signs has been researched in a laboratory study (Dewar, Kline, Schieber & Swanson, 1994) and found to significantly exceed that of legend signs (despite the high degree of variability in the study data) Read the entire page →
From page 70... ... The first guide sign assembly contains two numbers and two symbols, requiring 3.0 s of reading time; the second contains two designation names and two symbols, also requiring 3.0 s; and the third is a simple and familiar one-word regulatory sign, requiring 1 s. Thus the total sign reading time is 7.0 s. Read the entire page →
From page 71... ... Step 6: Develop Engineering Strategies for Improvement of Sight Distance Deficiencies Not conducted as part of this example. HFG TUTORIALS Version 2.0 22-34 Sign Legibility Distance (ft) Read the entire page →
From page 72... ... 22-35 HFG TUTORIALS Version 2.0 Tutorial 3: Detailed Task Analysis of Curve Driving A task analysis of the different activities that drivers must conduct while approaching and driving through a single curve (with no other traffic present) was conducted to provide qualitative information about the various perceptual, cognitive, and psychomotor elements of curve driving. Read the entire page →
From page 73... ... HFG TUTORIALS Version 2.0 22-36 Table 22-6. Driving tasks and information-processing subtasks associated with a typical curve. Read the entire page →
From page 74... ... • Groeger, J Read the entire page →
From page 75... ... HFG TUTORIALS Version 2.0 22-38 Tutorial 4: Determining Appropriate Clearance Intervals Methods for determining appropriate clearance interval length vary from agency to agency, and there is no consensus on which is the best method. The Institute for Transportation Engineers recommends several procedures for determining clearance interval duration in a 1994 informational report (see ITE, 1994) Read the entire page →
From page 76... ... 22-39 HFG TUTORIALS Version 2.0 Tutorial 5: Determining Appropriate Sign Placement and Letter Height Requirements When determining the appropriate sign placement, it is important to consider a number of driver-related factors. The Traffic Control Devices Handbook (Pline, 2001) Read the entire page →
From page 77... ... HFG TUTORIALS Version 2.0 22-40 Another method for calculating reading time, cited in previous studies, applies to complex signs in high-speed conditions. The formula provided is: After finding the reading time, convert it into a reading distance by multiplying by the travel speed. Read the entire page →
From page 78... ... 22-41 HFG TUTORIALS Version 2.0 Step 4. Calculate the Information Presentation Distance The information presentation distance is the total distance from the choice point (e.g., intersection) Read the entire page →
From page 79... ... HFG TUTORIALS Version 2.0 22-42 one symbolic arrow. The sign is placed 200 ft in advance of the intersection. Read the entire page →
From page 80... ... 22-43 HFG TUTORIALS Version 2.0 Tutorial 6: Calculating Appropriate CMS Message Length under Varying Conditions The amount of information that can be displayed on a CMS is limited by the amount of time that the driver has to read the message. This amount of time in turn is determined by the legibility distance of the sign and the traveling speed of the passing vehicle. Read the entire page →
From page 81... ... HFG TUTORIALS Version 2.0 22-44 Step 2. Use the Driver Speed to Find the Base Maximum Number of Information Units Allowed in a Message The maximum number of information units is derived from the legibility distance of the CMS (which depends on the technology used) Read the entire page →
From page 82... ... 22-45 HFG TUTORIALS Version 2.0 In general, permanent CMSs that are mounted over the roadway are not affected by crest vertical curves (Dudek, 2004) Read the entire page →
From page 83... ... HFG TUTORIALS Version 2.0 22-46 for Displaying Messages with Dynamic Characteristics. Although the blanking time was only tested between phases 1 and 2 (not between 2 and 1) Read the entire page →
From page 84... ... 22-47 HFG TUTORIALS Version 2.0 • Omit redundant information Example: Original Message: Shortened Message: MAJOR ACCIDENT MAJOR ACCIDENT ON I-276 NORTH PAST I-80 PAST I-80 2 LEFT LANES CLOSED 2 LEFT LANES CLOSED KEEP RIGHT If the CMS is on I-276, the same freeway as the accident, the information is evident to the drivers and may be omitted. The information units "2 Left Lanes Closed" and "Keep Right" are redundant because drivers can assume that if the two left lanes are closed, they will need to move to the right. Read the entire page →
From page 85... ... HFG TUTORIALS Version 2.0 22-48 Step 5C. Use Priority Reduction Principles If the message still contains more information units than should be displayed, the information units should be reduced in order of priority. Read the entire page →
From page 87... ... HFG TUTORIALS VERSION 2.1 22-50  Can exercise sound traffic safety and operational judgement. The HSM provides guidance for traditional descriptive methods of analysis for traffic safety, but also drives the practice forward with predictive methods for crash analysis. Read the entire page →
From page 88... ... HFG TUTORIALS VERSION 2.1 22-51 Together, the HSM and the HFG can supplement traditional sources of roadway design information and help improve decisions that reduce crash potential. They are both guidance documents intended to provide practitioners with practical information about quantitative crash reductions and human factors. Read the entire page →
From page 89... ... HFG TUTORIALS VERSION 2.1 22-52 Data is the basis for defining how to improve traffic safety performance and understanding how to reduce the number and potential for crashes at a particular site. The three critical types of data needed for this process include crashes, traffic volumes, and recent projects that might impact crash potential (e.g., lane widening projects, horizontal curvature, or the installation of new sidewalks) Read the entire page →
From page 90... ... HFG TUTORIALS VERSION 2.1 22-53 In some situations, crash data availability may be limited. The HSM and HFG are both driven by data and by addressing safety issues identified through data analysis. Read the entire page →
From page 91... ... HFG TUTORIALS VERSION 2.1 22-54 Step 2- Review Site and Existing Conditions 2a. Conduct a Site Visit Objective of Step 2a: Conduct a qualitative analysis of existing roadway, behavioral, and human factors conditions at the site. Read the entire page →
From page 92... ... HFG TUTORIALS VERSION 2.1 22-55 Figure 3. Existing Road Audit Prompt Sheet (Ward, 2006) Read the entire page →
From page 93... ... HFG TUTORIALS VERSION 2.1 22-56 Figure 4. Example of crashes by year and severity in both tabular and graphic layouts Figure 5. Read the entire page →
From page 94... ... HFG TUTORIALS VERSION 2.1 22-57 Develop a statement of significant trends and findings. Based on the totality of the crash/conflict record, a short summary of significant trends or findings should be developed. Read the entire page →
From page 95... ... HFG TUTORIALS VERSION 2.1 22-58 Figure 7. The Human Factors approach to road safety involves three factors We expand upon these factors in more detail below but, briefly, the ‘road user' factor includes capabilities and limitations such as age, training, road familiarity, experience, and possible impairment; the ‘environment' factor includes elements like road geometry, traffic control devices, and the luminance levels of signs and markings; and the ‘vehicle' factor includes automobile and truck components like tires, brakes, or special safety systems. Read the entire page →
From page 96... ... HFG TUTORIALS VERSION 2.1 22-59 given roadway location will also vary, and could range from roadway edges or markings, to signs or traffic control devices, to objects moving within the scene, such as pedestrians or bikes. Figure 8. Read the entire page →
From page 97... ... HFG TUTORIALS VERSION 2.1 22-60 Consider some other examples with multiple factors: 1. On a wet road, worn brakes or tires leading to increased stopping distances and an increased probability of a rear-end crash. Read the entire page →
From page 98... ... HFG TUTORIALS VERSION 2.1 22-61 When completing the HFIM, users should recognize that the individual elements and their interactions need to reflect the specific type of vehicles and types of road users using the infrastructure. For example, you can have large semi-trucks or some roads but not on others; e.g., some bridges and parkways. Read the entire page →
From page 99... ... HFG TUTORIALS VERSION 2.1 22-62 At this early stage in the process, it is best to generate a HFIM table that is inclusive of all possible factors impacting safety performance, rather than exclusive. Specifically, the HFIM should include any factors and combinations of factors (interactions) Read the entire page →
From page 100... ... HFG TUTORIALS VERSION 2.1 22-63  Consider not just the factors that were present at the exact time of a crash, but also factors or events that could have occurred prior to the crash. Step 3 - Identify Potential Countermeasures6 Step 3a. Read the entire page →
From page 101... ... HFG TUTORIALS VERSION 2.1 22-64  Suburban arterials, and  Urban arterials. For analysis of a site not included in the preceding list of SPFs, the predictive method may not be the most efficient option for evaluation potential site improvements. Read the entire page →
From page 102... ... HFG TUTORIALS VERSION 2.1 22-65 of the HSM is to realize when working with CMF's that they are statistics without causation and often have multiple CMFs from one research study. Human Factors is the bridge to better decisionmaking. Read the entire page →
From page 103... ... HFG TUTORIALS VERSION 2.1 22-66 determine the combined CMF of the treatments by multiplying them together. For example, if three treatments (Treatment 1, Treatment 2, and Treatment 3) Read the entire page →
From page 104... ... HFG TUTORIALS VERSION 2.1 22-67 Finally, go back to the individual Chapters/Guidelines/Tutorials cited in the HFIM and – for each candidate guidelines being considered for application – more closely examine the Design Guidelines, Discussion, and Design Issues subsections from the HFG in more detail. For each safety issue or risk listed in the HFIM, identify or list – as appropriate:8  Relevant road user needs, capabilities, or limitations,  Relevant road user perception or performance issues,  Specific HFG recommendations, countermeasures, or design options, and  Relevant data sources or research studies that could support specific design changes or enhancements. Read the entire page →
From page 105... ... HFG TUTORIALS VERSION 2.1 22-68 selection and improve the level of safety performance for new or upgraded roadways. However, to get the most value out of the joint use of the HSM and HFG, the options and countermeasures provided by each document must be collated, compared, and considered as part of the prioritization process. Read the entire page →
From page 106... ... HFG TUTORIALS VERSION 2.1 22-69  Conflicts- Does the project create any built, operational, or road user problems with the existing area. E.g., will driveway entries/exits become additional elements for residents/businesses/bikes/pedestrians/less mobile individuals using the road? Read the entire page →
From page 107... ... HFG TUTORIALS VERSION 2.1 22-70 Step 5- Conduct Safety Effectiveness Evaluation Objective of Step 5: To quantitatively assess the safety performance change of the completed project. The purpose of a safety effectiveness evaluation is to determine the actual impacts of a project after it has been completed at a site. Read the entire page →
From page 108... ... HFG TUTORIALS VERSION 2.1 22-71 TUTORIAL 8: USING THE HFG TO SUPPORT A ROAD SAFETY AUDIT (RSA) A valuable way to use the HFG is to use it to incorporate human factors issues and solutions into the Road Safety Audit (RSA) Read the entire page →
From page 109... ... HFG TUTORIALS VERSION 2.1 22-72  Step 3: Conduct a Pre-audit Meeting to Review Project Information and Drawings  Step 4: Conduct Review of Project Data and Conduct Field Review  Step 5: Conduct Audit Analysis and Prepare Report of Findings  Step 6: Present Audit Findings to Project Owner/Design Team  Step 7: Prepare Formal Response  Step 8: Incorporate Findings into the Project when Appropriate Step 1 is identifying the road or project to be audited and Step 2 involves picking the RSA team.  In Step 1, the greatest benefits to using the HFG will be obtained on RSA projects where there is some a priori reasons for believing that driver errors related to the roadway design are taking place and impacting safety performance  In Step 2, including someone with human factors experience or someone with experience using human factors design tools like the HFG is a good idea, especially if there are any specific concerns regarding road user behavior, capabilities, or limitations. Read the entire page →
From page 110... ... HFG TUTORIALS VERSION 2.1 22-73  Step 4 includes a more detailed review of design drawings and project data, as well as a field review of the site. From the HFG perspective that seem most relevant., the goal in this step is to review the relevant design information and crash history associated the facility being audited and to create a list of HFG topics and materials that reflects the facilities' design features and safety concerns. Read the entire page →
From page 111... ... HFG TUTORIALS VERSION 2.1 22-74 Step in the RSA Process Ways to Use the HFG Evaluate risks and prioritize safety concerns Are the differences between the "as-built" specifications and the HFG recommendations likely to result in safety benefits? Do the HFG materials provide other insights or countermeasures into known or correctable safety issues? Read the entire page →
From page 112... ... HFG TUTORIALS VERSION 2.1 22-75 TUTORIAL 9: SUMMARY OF HFG TOPICS Part III HF Guidance for Roadway Location Elements 5-1 Chapter 5: Sight Distance Guidelines 5-2 Key Components of Sight Distance The required sight distance is the sum of the distance traveled during Perception-Reaction Time (PRT) while the driver notices a hazard or situation, decides what to do, and begins a response plus the Maneuver Time (MT) Read the entire page →
From page 113... ... HFG TUTORIALS VERSION 2.1 22-76 6-8 Countermeasures for Improving Steering and Vehicle Control Through Curves This guideline describes how to select curve geometries that help drivers maintain proper lane position, speed, and lateral control through curves. It includes quantitative guidance on curvature, spiral length, and reverse curves. Read the entire page →
From page 114... ... HFG TUTORIALS VERSION 2.1 22-77 10-8 Sight Distance at Left-Skewed Intersections Drivers at these intersections need to look backwards over their right shoulder and past parts of their own vehicle. This guideline presents the geometry and tables to calculate the available sight distance from the skew angle, set back distance, and properties of typical vehicles. Read the entire page →
From page 115... ... HFG TUTORIALS VERSION 2.1 22-78 13-1 Chapter 13: Construction and Work Zones 13-2 Overview of Work Zone Crashes This guideline characterizes work zone crashes and provides a framework for work zone design. It specifies the need for additional driver guidance in work zones based on the number, type and severity of crashes occurring in work zones. Read the entire page →
From page 116... ... HFG TUTORIALS VERSION 2.1 22-79 15-4 Methods to Increase Compliance at Uncontrolled Crosswalks This guideline discusses several treatments available for uncontrolled crosswalks and provides statistics for driver and pedestrian compliance with each. 15-6 Methods to Reduce Driver Speeds in School Zones Traffic control devices and pavement markings are used to encourage drivers to slow for school zones. Read the entire page →
From page 117... ... HFG TUTORIALS VERSION 2.1 22-80 17-12 Speeding Countermeasures: Communicating Appropriate Speed Limits This guideline discusses best practices for communicating posted speed limits to drivers and explains when to use approaches such as redundant signs, active speed warning, and in-pavement measures. 17-14 Speeding Countermeasures: Using Roadway Design and Traffic Control Elements to Address Speeding Problems Geometric elements and traffic control devices both affect speed-related crashes. Read the entire page →
From page 118... ... HFG TUTORIALS VERSION 2.1 22-81 19-12 Changeable Message Signs for Speed Reduction Changeable message signs can be used to alert drivers to the need to reduce their speed for temporary conditions such as work zones, adverse weather, incidents, or heavy congestion. This guideline provides principles on the wording and placement of changeable message signs to achieve speed reductions. Read the entire page →
From page 119... ... HFG TUTORIALS VERSION 2.1 22-82 28-1 Chapter 28: Pedestrians 28-2 Task Analysis of Pedestrian Crossing in a Multiple Threat Scenario In the multiple threat scenario, a pedestrian crossing in front of a stopped vehicle is at risk of being struck by a second vehicle traveling in the adjacent lane. This guideline shows the interactions that can take place between pedestrians and drivers and countermeasures for reducing conflicts in this scenario. Read the entire page →
From page 120... ... HFG TUTORIALS VERSION 2.1 22-83 29-8 Separated Bicycle Lanes Separated bicycle lanes are one or two-way exclusive bikeways parallel to the roadway yet physically separated from moving traffic. They can provide increased safety and comfort for bicyclists in areas with higher traffic volumes and speeds. Read the entire page →

From page 38...

... HFG TUTORIALS VERSION 2.1 22-1 CHAPTER 22 TUTORIALS TUTORIALS FROM NCHRP REPORT 600: HUMAN FACTORS GUIDELINES FOR ROAD SYSTEMS Tutorial 1: Real-World Driver Behavior Versus Design Models...……………………….……22-2 Tutorial 2: Diagnosing Sight Distance Problems and Other Design Deficiencies.…………….22-9 Tutorial 3: Detailed Task Analysis of Curve Driving.………………………………………...22-35 Tutorial 4: Determining Appropriate Clearance Intervals…………………………………….22-38 Tutorial 5: Determining Appropriate Sign Placement and Letter Height Requirements...…...22-39 Tutorial 6: Calculating Appropriate CMS Message Length under Varying Conditions...……22-43 NEW TUTORIALS Tutorial 7: Joint Use of the Highway Safety Manual (HSM) and the Human Factors Guidelines for Road Systems (HFG)