To determine the reliability of police accident report (PAR) data for crashes involving serious injury, we compared the direction of initial force derived from the PAR with that reported by an experienced crash investigation team (CIT) that conducted on-scene inspection of seventy-three vehicles with a discernible primary impact. The CIT data were taken as the reference information. Multiple investigators interpreted the direction of initial force from the PAR by using text descriptions of the collision as well as diagrams depicting the point of initial impact, areas of the vehicle damaged, and collision type (interrater variation 13.9 degrees). Data were recorded in increments of 5 degrees from 0-360 degrees. The mean difference in determined direction of force between the PAR and the CIT was 18.0 degrees. Although the PAR is of limited value for determination of direction of initial force direction in individual collisions, the variability from reference in aggregate data is within acceptable limits. The relative concordance of the two data sources allows for the study of injury patterns and biomechanics by the linkage of readily available trauma registries and police accident report data.