Guidebook on Identification of High Pedestrian Crash Locations

CHAPTER 2. SELECT APPROACH

OVERVIEW

The identification of locations that cause concern for pedestrian safety can be accomplished using any of the following approaches, either alone or in combination:

• A traditional approach (also known as a “reactive approach”) is generally based on an observed or historical crash pattern that suggests a problem exists. These locations have historically been called “hot spots” or “black spots.” Existing crash data along with roadway data and perhaps volume data are used to identify the locations. In some cases, an index may be developed to integrate other conditions, such as lack of sidewalks, into the process of identifying these locations of concern.
• A proactive approach uses models—such as safety performance functions (SPFs)—to determine the expected number of crashes (or crash frequency) for locations within a set region. These estimates can be used to prioritize the sites that may potentially need treatments. The approach is called proactive because it addresses a potential risk rather than an experienced problem. Treatments installed at locations identified using risk factors or known land uses are additional illustrations of proactive approaches, for example, installing a pedestrian crossing treatment when a bus stop is added to a five-lane arterial across the street from a large apartment complex. SPFs that could be used within a proactive approach are available in the HSM.⁽²⁾ Another example of a proactive approach that is gaining in use is the systemic approach. The FHWA website on the systemic approach notes:
• Rather than managing risk at certain locations, a systemic approach takes a broader view and evaluates risk across an entire roadway system. A system-based approach acknowledges crashes alone are not always sufficient to determine what countermeasures to implement, particularly on low-volume local and rural roadways where crash densities are lower, and in many urban areas where there are conflicts between vehicles and vulnerable road users (pedestrians, bicyclists, and motorcyclists).⁽¹⁰⁾
• A systemic highway safety improvement uses a particular countermeasure or set of countermeasures implemented on all roadways or roadway sections where a crash type or risk factor is linked with a particular roadway or traffic element. Locations being treated are not based on the frequency or rate of crashes at a location, but on an analysis of which roadways or roadway sections have the given risk factor or crash type that may be mitigated by the improvement.
• A combination approach uses characteristics of both a traditional approach and a proactive approach, for example, a composite score that includes crash frequency along with predictions from a safety performance function.

APPROACHES CURRENTLY USED TO IDENTIFY PROBLEM LOCATIONS

NCHRP Synthesis 486, State Practices for Local Road Safety, documented the processes being used for identifying locations with local road safety concerns.⁽¹¹⁾ The synthesis considered all crash types and was not limited to pedestrians. The objective of the synthesis was to document State programs and practices that address local road safety. The most frequent response from State departments of transportation (DOTs) regarding problem identification was a combination of both traditional (reactive) and proactive methods. The survey indicated the following as the most frequently applied criterion for prioritizing local safety projects:

• Cost-benefit analyses (28 States).
• Crash history (26 States).
• Available funding (25 States).

The conducted survey found that fatal and serious injury crash numbers and crash rates were the major performance measures used.⁽¹¹⁾

THIS DOCUMENT

This document focuses on the traditional (reactive) approach to the identification of locations of concern. The Systemic Pedestrian Safety Analysis, created as part of NCHRP Project 17-73, provides information on conducting a systemic analysis for pedestrians using a proactive approach.⁽⁴⁾