Anticipating injury death controlling for new variables on southern California highways.pdf

1-12 ANTICIPATING INJURY DEATH: CONTROLLING FOR NEW VARIABLES ON SOUTHERN CALIFORNIA HIGHWAYS By Jianming Ma Graduate Student Researcher The University of Texas at Austin 6.9 E. Cockrell Jr. Hall, Austin, TX 78712-1076 Email: mjming@ Kara M. Kockelman (Corresponding Author) Clare Boothe Luce Assistant Professor of Civil Engineering The University of Texas at Austin 6.9 E. Cockrell Jr. Hall, Austin, TX 78712-1076 Phone: 512-471-0210 FAX: 512-475-8744 Email: kkockelm@ To be Presented at the 83rd Annual Meeting of the Transportation Research Board January 2004, Washington D.C. ABSTRACT This study investigates the relationship between occupant injury and a host of other factors, including traffic and weather conditions present at the time of crash, road design, vehicle type, and occupant characteristics. Crash and traffic-detector data from six Orange County freeways were used in an ordered probit model. Crash outcomes were classified for each occupant, as no injury, non-visible injury, visible injury, severe injury, and fatal injury. Higher design speeds (holding speed limits fixed) and speeding contribute to injury severity, while lighting and pavement surface conditions appear to play no role. Consistent with the literature, sideswipe and rear-end collisions result in less severe injury, relative to other collision types (such as broadside, hit-object, and rollover), while females and older persons are at higher risk of injury. Information on current traffic conditions proved very valuable for injury severity prediction. And a variety of design and policy recommendations can be drawn, to enhance highway design and roadway safety. Key words Crash analysis, injury severity, traffic safety, ordered probit model, Southern California Introduction Highway traffic crashes result in more loss of human life (as measured in human-years) than any other mode of transport in the U.S. (1). While vehicles and many roadw