This paper describes the Traffic Accident Information System (TAIS) developed for the City of Los Angeles Dept. of Transportation. LADOT decided to modify their existing TAIS to incorporate GIS capabilities while maintaining the accident database in an Oracle RDBMS. In the LADOT legacy database, all intersection and nonintersection accidents were referenced from street intersection, and the accidents were measured from intersection curb line. This referencing system of accidents made it challenging to geocode and display all accidents either on a route system for nonintersection accidents or within an intersection profile for intersection accidents. Due to the unique nature of the existing referencing system it was decided that a route system would be developed to include routes for each street feature between two consecutive intersections. This route system was then used to create spatial references for all accidents in the legacy database that was imported into Oracle. The route system and the customized route-editing tool were developed in ARC/INFO. If any editing is required on the already created route system, users will use this AML-based route-editing tool to update their route system data. An ArcView GIS application was then developed to display the accidents maintained in an Oracle database either on the route system or in an intersection profile. During the development of this application it was found that on-the-fly creation of spatial references for the accidents with a route system of about 72,000 routes was a very slow and inefficient process. To improve the situation, an ArcView GIS module was developed to create spatial references for all accidents in the Oracle database using complex algorithms. Spatial references included route ID, route measure, and geographical coordinates. These references were stored in an Oracle database and later were used to display nonintersection and intersection accidents on the LADOT route system and intersection profile, respectively. The paper reports on the structure of the database, methodology and development of the route system, spatial references for accident database, and display of those spatially referenced accidents.