Guide to Pedestrian Analysis (2022) / Chapter Skim
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29 In 2017, 5,977 pedestrians died in traffic crashes. Although this was a slight decrease from 2016, the general trend since 2009, when 4,109 pedestrians died, has been ever-increasing numbers of pedestrians being killed in traffic crashes.
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30 Guide to Pedestrian Analysis Estimating Pedestrian Exposure This section presents resources for estimating pedestrian exposure. It provides examples of risk assessment methods that can be applied to different geographic scales and roadway system elements.
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Consideration Basis for Defining Exposure Population Trips Volumes Distance Time Appropriate uses Areawide analysis when detailed information about pedestrian activity is infeasible to collect Assessing pedestrian and bicyclist behavior in large areas; walking trip common characteristics Compare exposure at the areawide level, i.e., for a specific jurisdiction Estimating pedestrian volume and risk at a specific location Comparison of exposure at the micro level, i.e., for specific transportation facilities Estimating exposure at micro and macro levels Estimating whether pedestrian risk increases with distance traveled Assessing how crossing distance affects risk Estimating exposure at micro and macro level Estimating whether pedestrian risk increases linearly with walking time Comparing risk between travel modes Comparing risk between different length crossings and individuals with different walking speeds Data sources American Community Survey: population by segment Travel demand surveys showing propensity to make walking trips on a regular basis Travel surveys Manual or automated counts Travel surveys Manual or automated counts of pedestrians, combined with the length of the specific area or corridor of interest Travel surveys Manual or automated counts of pedestrians and the measurement of the time traveled Advantages Easy to obtain and low-cost data available for most geographic regions Can adjust for differences in the underlying resident population of an area Vehicular volume likely to be related to area population Only way to represent exposure if no direct measurements are available Appropriate for use in large areas Best metric for assessing relationship of walking with trip purpose Trips can be assessed as a function of person, household, and location attributes Relatively simple to collect as opposed to measures such as distance or time Data collection can be costly if done for longer durations Automated methods for counting are improving over time More information than manual or automated pedestrian counts alone Can be used to measure exposure at micro and macro levels Common measure of vehicle exposure More information than manual or automated counts alone Can be used to measure exposure at micro and macro level Accounts for the traveler speed and different paths taken by the traveler to reach the destination Allows for accurate comparison between travel modes Disadvantages Does not accurately represent levels of pedestrian activity Does not account for distance or time that pedestrians are exposed to traffic Does not accurately represent levels of pedestrian activity Does not provide enough detail needed to assess risk at specific locations Trip-based measures are not meaningful for facility-specific geographic scales Does not differentiate by walking speed, age, or other factors that may influence individual risk Does not account for time or distance walked Does not account for exposure over a macro level, i.e., city, county Relatively difficult to collect data Assumes risk is equal over distance traveled Does not account for traveler speed or different paths taken by the traveler Relatively difficult to collect data Assumes risk is equal over entire time traveling Time spent is overestimated Trips are underreported, i.e., short trips are usually forgotten by people Common measures Number of people in an area, potentially segmented by age, gender, race, socioeconomic status, and so on; number of people in an area who walk regularly Number of trips, possibly by purpose Number of pedestrians per time period; number of people crossing; average daily, weekly, or annual pedestrian volume; product of pedestrian and vehicle volumes (interactions) Total or average miles traveled per pedestrian, total or average miles crossed per pedestrian Total or average amount of time spent traveling, total or average time taken by pedestrian crossing an intersection Source: Adapted from "Estimating Pedestrian Accident Exposure: Protocol Report" (5)
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32 Guide to Pedestrian Analysis considering exposure, cannot evaluate whether relative risk has changed. Have more crashes occurred because more people are walking, or have more crashes occurred even though walking activity has remained comparatively steady?
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Pedestrian Safety Analysis 33 • Areawide scales: – Network (trac analysis zone, census tract, census block group)
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34 Guide to Pedestrian Analysis out robust pedestrian safety analyses adapted from Road Safety Fundamentals: Concepts, Strategies, and Practices that Reduce Fatalities and Injuries on the Road (9)
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Pedestrian Safety Analysis 35 Sketch Planning -- Areawide Analysis Sketch planning includes methods for estimating exposure that are simple to apply and provide an alternative to complex models. They may be implemented in a spreadsheet or geographic information system (GIS)
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36 Guide to Pedestrian Analysis Network Analysis Model – Specific Transportation Facilities Network analysis models are much more complex than sketch planning models and are based on a pedestrian network representation. They typically use a four-step modeling approach for trip generation and distribution.
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Pedestrian Safety Analysis 37 Direct Demand Model -- Specific Transportation Facilities Direct demand models are among the most widely used tools for pedestrian volume estimation and modeling. These models are also used as primary tools in measuring pedestrian exposure in safety analysis.
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38 Guide to Pedestrian Analysis Discrete Choice Model -- Specific Transportation Facilities Discrete choice models utilize information about crossings and crossing behavior to model pedestrian crossing behavior. Crash risk exposure can be estimated for any location along a pedestrian trip where a pedestrian interacts with a vehicle (i.e., a location where a pedestrian is likely to cross)
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Pedestrian Safety Analysis 39 A second consideration is that crashes in general, and pedestrian crashes in particular, are relatively rare events. A sharp increase in the number of crashes at a location in a given year is often due to random chance and not necessarily an indication that the location is less safe relative to other similar locations.
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40 Guide to Pedestrian Analysis The systemic approach is more data- and analysis-intensive than the crash-based approach, but, at the same time, the data-driven nature of the approach provides a more consistent and equitable process of project selection as compared with addressing individual problems as they arise (27)
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Pedestrian Safety Analysis 41 • Tra c calming (e.g., minicircles, chicanes, speed tables) , • Tra c management (e.g., street closures, le -turn prohibitions)
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42 Guide to Pedestrian Analysis lanes, higher vehicle AADT, and speed limits, the following measures can also be considered: visibility enhancements such as advanced yield or stop lines; pedestrian refuge islands; and actuated pedestrian signals, including RRFBs and pedestrian hybrid beacons. Once potential countermeasures have been identified, they can be evaluated for their ability to address the safety issue being studied.
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Pedestrian Safety Analysis 43 Countermeasure CMF or Other Estimated Pedestrian Safety Benefit Example High-visibility crosswalk -- vertically arranged street markings designed to improve the visibility of the crosswalk as compared with traverse parallel lines. 0.52 in urban locations (35)
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44 Guide to Pedestrian Analysis Table 3-2. (Continued)
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Pedestrian Safety Analysis 45 Countermeasure CMF or Other Estimated Pedestrian Safety Benefit Example Leading pedestrian interval -- provides pedestrians with a 3- to 7-second head start when entering an intersection relative to the green signal for parallel vehicular traffic.
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46 Guide to Pedestrian Analysis Countermeasure CMF or Other Estimated Pedestrian Safety Benefit Example Curb extension -- an extension of the pedestrian space at intersections designed to increase the visibility of crossing pedestrians and reduce their crossing distance No CMFs yet available; nonetheless, speed reductions in some applications (50) Source: pedbikeimages.org/Kristin Langford.
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Pedestrian Safety Analysis 47 Crash Type Candidate Countermeasure Midblock. The pedestrian walked or ran into the roadway at an intersection or midblock location and was struck by a vehicle.
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48 Guide to Pedestrian Analysis State Highway and Transportation Officials' Highway Safety Manual, 1st ed.
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Pedestrian Safety Analysis 49 crossing (which is related both to driver yielding and whether a su ciently long gap in tra c existed when the pedestrian arrived)
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50 Guide to Pedestrian Analysis 3.
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Pedestrian Safety Analysis 51 24.
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52 Guide to Pedestrian Analysis 46. Fayish, A
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Pedestrian Safety Analysis 53 67.
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