Collision diagrams are graphic representations of intersections, ramps, or sections of roadway that provide detailed information about accidents at a specific location. The main purpose of collision diagrams is to serve as depictions of accident patterns, and they are used to evaluate specific sites for possible causes of accidents. Currently, the Washington State Department of Transportation manually constructs these diagrams. However, this study found collision diagrams could be produced with automated technology without changing the data structure of WSDOT's accident data files.
This study examined literature and existing software that other transportation agencies or vendors use to construct collision diagrams. This examination determined that computer generated diagrams created with that software lack graphic detail of individual intersections, are limited to a specific data structure, and are limited to two or three generic intersection depictions. Several alternative means to construct enhanced diagrams were examined, including artificial intelligence (AI) techniques, to find a way to offer a more robust assortment of graphics.
A prototype system for producing automated collision diagrams was developed. This Washington Automated Collision Diagramming System (WACDS) has the following advantages over previous systems: (1) WACDS integrates the technologies of computer-aided drafting (CAD) and database management to provide improved graphic detail and ease of utility; (2) WACDS uses WSDOT's current accident file data structures; (3) WACDS is modular and can be modified, expanded, or shared without major software revision.
The report discusses a strategy for fully implementing WACDS at WSDOT, in addition to a schedule for implementation.