Civil and Environmental Engineering


Date of this Version



Published in Transportation Research Record 2672(32), Volume: 2672 issue: 32, page(s): 94-106


© National Academy of Sciences: Transportation Research Board 2018

Published by SAGE Publications. Used by permission.


The response time of Emergency Medical Services (EMS) to road accidents can be the difference between life and death. The California strategic highway safety plan highlight the need to improve the response time and recognizes that: 37% and 8% of the fatal crashes are 30 or more miles away from a trauma center in rural and urban areas respectively.

The paper seeks to: (1) demonstrate the viability of using spatial multi-criteria analysis in road safety management, and (2) provide a good scientific justification in selecting optimal counties for EMS posts. The goal is to propose areas that are close to probable fatality points in order to achieve a maximum response time of 10 minutes (i.e., 3 minutes below the national average).

This paper adopted a multi-criteria analysis using the weighted linear combination method on raster data of various impact factors. The land selection criteria were: (1) close to probable road fatality locations, (2) far from existing trauma centers, (3) close to existing rest stop areas, and (4) not on protected lands or bodies of water.

The method proved viable and the analysis resulted in 37,387 square miles of suitable land areas. About 7% moderately suitable and 69% were unsuitable. The highway corridors linking the counties between Los Angeles and San Francisco were the most suitable locations. Other identified high suitable areas were predominantly rural counties such as Amador and Calaveras. A benefit-cost analysis is recommended in future studies to determine the suitability of specific sites within the identified counties.