research >>pedestrian safety >>pedestrian exposure

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Pedestrian Exposure Measures

California has a higher percentage of pedestrian fatalities per traffic fatalities overall than the national percentage: between 17.2 percent and 20.2 percent, compared to 11.2 percent to 12.6 percent over four recent years.

California's State Highway System has a disproportionate share of pedestrian fatalities, compared to its mileage: 23 percent of fatal pedestrian collisions occur on state highways, but they account for only 10 percent of the total mileage.

To make efficient use of limited resources, interventions must be targeted at areas with high pedestrian collision rates. Unfortunately, creating reliable estimates of pedestrian collision rates is impossible without adequate information about pedestrian exposure to accidents. There is currently no systematic and accessible method that is widely used to estimate pedestrian exposure. The goal of the project is to develop tools for estimating pedestrian risk for injury, with the objective of developing a method or set of methods for estimating pedestrian volume for calculation of pedestrian accident rates in California. Such tools include definitions of exposure and risk, methods for measurement, and analytic techniques.

The primary research product is a protocol for measuring pedestrian volume at local and state levels that will allow Caltrans to monitor pedestrian safety trends across the state. This protocol could also be used by community groups and other researchers to obtain location-specific data and to build a state-wide integrated pedestrian volume database.

The project has the following objectives:

• Develop a conceptual framework and definitions for pedestrian exposure
• Review, test, and evaluate and test manual and video counting methods.
  Develop a prototype for a pedestrian exposure database that could be maintained by agencies at various levels (neighborhood, city, corridor, state)
• Develop and test formal protocol and training presentation for measuring pedestrian exposure.
• Review and test automated counting methods. If such methods prove to be efficient and useful we will include them in the protocol
• The measuring protocol will include instructions for how to:
  • Decide where to collect data
  • Decide exactly what data to collect
  • Decide which counting instrument or approach is best for the location
  • Decide how many observations to make and when to make them
  • Calculate daily/weekly/monthly/yearly pedestrians volumes (by total count, or by time/distance exposure measures) for a location, determine how to aggregate data to get overall walking rates of a larger area (corridor, town, county, state)

TSC Resources

"Efffectiveness of a Commercially Available Automated Pedestrian Counting Device in Urban Environments: Comparison with Manual," Ryan Greene-Roesel, Mara Chagas Diogenes, David R. Ragland, and Luis Antonio Lindau. Presentation at the 2008 TRB Annual Meeting.

"Estimating Pedestrian Accident Exposure (three reports with links in following paragraph):" defining pedestrian exposure and evaluating methods for measuring it within the state of California. 1. "Automated Pedestrian Counting Devices Report"; 2. "Protocol Report; and 3. "Approaches to a Statewide Pedestrian Exposure Database." (March 2007)

"Why Pedestrians and Bicyclists Should Count: TSC Director David Ragland Explains Key Findings about California's Unique Pedestrian Safety Issue" TSC Online Newsletter, Fall 2006.

"Space Syntax: Innovative Pedestrian Volume Modeling Tool for Pedestrian Safety." Raford, N. Ragland, DR. Presentation at the Transportation Board Annual Meeting, Washington D.C. January 11-15, 2004.

"Safety in Numbers: Surprising insights into how streets and buildings shape driver and pedestrian interactions" TSC Online Newsletter, Spring 2004.

"Space Syntax: An Innovative Pedestrian Volume Modeling Tool for Pedestrian Safety" Noah Raford, David R. Ragland. TSC Research Report. 2003.