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The Traffic Deaths indicator measures the percent deaths within each census tract based on all accident death counts. The number of traffic deaths in the census tract is divided by the census tract population multiplied by 100 to determine the percent deaths. Traffic deaths data from 2010 to 2019 for this indicator were collected directly from the Fatality Analysis Reporting System (FARS). The geocoded crash data were combined to the census tract level for equity analysis.
Indicator Specific Method
The United States Department of Transportation developed the Fatality Analysis Reporting System (FARS), National Highway Traffic Safety Administration (DOT, NHTSA) in 1975 to provide a comprehensive measure of highway safety and help identify traffic safety problems. A nationwide census provides yearly data regarding fatal injuries hurt in motor vehicle traffic crashes. A crash must involve a motor vehicle traveling on a traffic way ordinarily open to the public and must result in the death of at least one person (occupant of a car or a non-motorist) within 30 days of the crash included in FARS.
Statewide crashes with all severities from 2010 to 2019 are mapped and spatially joined with census tracts to determine their total number of crashes within each census tract. Then, the number of deaths is divided by that sum of crashes to determine the percent deaths within each census tract. FARS crash data include geospatial information on accidents and detailed personal information on gender and age, and the data provide insights regarding equity issues. When using transportation safety data, it is imperative to fully understand the dataset to avoid bias caused by missing data.
Rationale:
Various studies on traffic safety have primarily focused on injuries or deaths caused by motor vehicle accidents. Road, traffic, employment density, race, and income level have been used as independent variables in those studies. Crash rate or injuries counts, and loss of life have been used to quantify traffic safety for equity when conducting cost-benefit analysis. Moreover, studies of equity between races quantified crash rate as the number of people from a specified population injured in a census tract divided by the total population of that census tract.
From Caltrans’ perspective, safety countermeasures such as signalization, markings, and operational upgrades, geometric design, systemic safety projects, signs, and Intelligent Transportation Systems (ITS) can be taken to decrease the number of traffic injuries and fatalities. Systemic safety planning could be adopted to evaluate the entire system using a defined set of criteria to identify possible locations for safety investments to reduce the occurrence of and the potential for severe crashes.
Systemic safety projects can be applied over an entire corridor to reduce crashes and risks along the whole corridor, help widen traffic safety efforts, and consider risk and crash history when finding where to make low-cost safety improvements. The Federal Highway Administration (FHWA) has nine recognized safety countermeasures such as road diets, medians and pedestrian crossing islands, pedestrian hybrid beacons, roundabouts, access management, retroreflective backplates, safety edge, enhanced curve delineation, and rumble strips that can be implemented depending on local transportation safety realities.
Data Source(s)National Highway Traffic Safety Administration, Fatality Analysis Reporting System (2021). Run a Query Using the FARS Web-Based Encyclopedia. CSV