UC Irvine Institute of Transportation Studies

This study uses Los Angeles County as the setting for examining the full economic costs of truck-related freeway incidents. Los Angeles County was selected as a setting due to its size--over 7.5 million population in an area of 4,080 square miles, the highly developed nature of its freeway system (504 miles of freeway), the heavy truck traffic on that system (over 12 million truck miles of travel per day), and the availability of data to facilitate analysis of this problem. 

Another reason for using Los Angeles as the site for this study is that truck-related incidents are a significant and growing problem on the Los Angeles freeway system, one which the California Department of Transportation is also examining. The majority of major incidents on the Los Angeles freeway system involve one or more trucks. During 1983, 1984, and 1985, 424 major incidents--defined as an incident which closes at least two lanes and is predicted to last at least two hours--involving trucks occurred on the freeway system. In other words, a major truck-related incident occurred nearly three out of every five working days of the week. Moreover, data collected for this study indicates that 6,700 to 8,000 total truck incidents occur annually on the Los Angeles County freeway system, or approximately 20 to 25 truck incidents per weekday. The scope of the problem in Los Angeles makes it an excellent setting for analyzing the costs of truck-related freeway incidents.