Based on a minor amount of related research and pedestrian-motor vehicle crash typing research, there is a believed to be a strong, but unquantified relationship between pedestrian/motor vehicle crashes and site-specific characteristics. Models are currently not available that can help predict crashes based on site-specific conditions and operational characteristics of a roadway.

A coordinated effort is underway to develop a Highway Safety Manual (HSM) for use in making quantitative estimates of the safety performance of specific highway types and quantitative estimates of proposed improvements to specific highway types. The highway types being addressed in the first edition of the HSM are rural two-lane highways, rural multilane highways, and urban and suburban arterials. Explicit consideration of pedestrian safety on urban and suburban arterials is considered critical to implementation of the first edition of the HSM.

An HSM methodology to make safety predictions for urban and suburban arterials is being developed in the ongoing NCHRP Project 17-26. The Project 17-26 database will be most suited for modeling motor vehicle crashes on roadway segments and at intersections. Models will also be developed within Project 17-26 that estimate pedestrian safety based on average pedestrian crash frequency. However, these models will not be sensitive to site-specific conditions that influence pedestrian crashes. Thus, the models currently under development will not address the needs for determining site-specific pedestrian safety effects or for evaluating the site-specific effects of proposed projects intended to improve pedestrian safety.

The objective of this research is to develop a methodology for quantifying the pedestrian safety effects related to existing site characteristics and/or proposed improvements on urban and suburban arterials. The methodology should be developed so it can be used in an independent fashion as a guide, but also in a manner that will allow integration with the overall safety performance methodology currently under development in NCHRP Project 17-26.

The following activities are anticipated as part of this research project: (1) Conduct a review of completed and ongoing research to identify methodologies that may be appropriate for predicting pedestrian safety effects related to roadway geometrics and other factors. (2) Identify the candidate model inputs and the data needs for the development of the methodology. Consideration should be given the model inputs and data needs identified in NCHRP Project 17-26. Strong consideration should be given to integrating the crash typing methodology to explore how pedestrian crash typing, together with roadway geometrics and motor vehicle operational data, can predict crashes. (3) Acquire the data needed to develop the pedestrian safety prediction models. Consideration should be given to using the database developed for NCHRP Project 17-26 and supplementing the database with variables specifically required for pedestrian safety modeling, such as pedestrian volumes and pedestrian facility features. Modeling of pedestrian crashes typically requires larger sample sizes than modeling of motor-vehicle crashes. Therefore, additional potential data sources should also be investigated. At least two Canadian cities have roadway and/or intersection data, including pedestrian volumes that may be suitable for this effort. Given that most communities do not have large data sources for pedestrian volumes, the study should be sensitive to forecasting crashes without being dependent on pedestrian volume data. (4) Develop pedestrian safety prediction methodology and a set of counter-measures for the most common predicted geometric conditions for crashes. Any safety predictive models for pedestrian crashes should be developed in a manner that can be integrated with the HSM safety prediction methodology for urban and suburban arterials being developed in Project 17-26. This approach is intended to assure that the HSM safety prediction methodology for urban and suburban arterials is sensitive to site-specific factors that influence pedestrian crashes.

Note: The AASHTO Standing Committee on Research increased funding to $400,000 and noted that the project should be phased, with an early assessment of the likelihood of success.

Status: This project was incorporated into NCHRP Project 17-26 and has been completed.

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