This helps identify those geometric, traffic, and driver-related factors leading to severe crashes at those intersections. Thus, the main objective of this study is to identify the significant factors that contribute to injury severity at unsignalized intersections. Six counties (Orange, Hillsborough, Brevard, Seminole, Leon, and Miami-Dade) in Florida were specifically selected so as to geographically represent the state of Florida. In this study, crash injury severity is analyzed at 1,547 three-legged and 496 four-legged unsignalized intersections (i.e., a total of 2,043 intersections, including stop-controlled, yield-controlled and non-controlled intersections) in the state of Florida in 4 years (from 2003 to 2006) using the ordered probit, binary probit, and nested logit methodologies. The use of the ordered probit model formulation in this study was deemed more beneficial than multinomial logit and probit models because while accounting for the categorical nature of the dependent variable, they do not account for the ordinal nature of the modeled response categories (Duncan, Khattak, & Council, 1998), which can be a serious issue. The most common statistical frameworks for analyzing crash severity are multinomial logit, ordered probit, and nested logit models (Abdel-Aty, 2003, Chang & Mannering, 1999, Savolainen & Mannering, 2007). This study focuses on analyzing crash injury severity with respect to its inherently ordered nature, not its frequency.

Crash injury severity is considered the most serious crash outcome, which is the core of this paper. This helps identify appropriate countermeasures for any observed safety deficiency. Identifying those geometric and traffic factors leading to severe crashes at unsignalized intersections is an essential task of traffic safety analysts. One of the frequent types of intersections is unsignalized intersections, which include intersections with stop control, yield control, and no traffic control. In 2004, Florida led the nation in intersection fatalities, where 30% of fatalities occurred at intersections. According to the Florida Department of Transportation (2006), almost one in every four fatal crashes occurs at or near an intersection. For this reason, a thorough understanding of them needs to be achieved in order to design them in the best possible manner.

Intersections, constituting some of the most representative features of any transportation system, are considered to be those entities with a complex nature.

Crash time 4 ordinal not found