High crash corridors are grouped into two categories: Frequencies and Rates:
High Crash Frequencies
The total number of CMV crashes resulting in a death (K), serious injury (A), or known injury (B). These layers do not account for truck traffic volume.
High Crash Rate
The number of crashes as compared to the traffic volume. Crash rates are calculated by dividing the total number of crashes at a given roadway section over a five-year time period.
There are a number of corridors where both high crash rates and high crash frequencies overlap. These are defined as ‘high intensity corridors’.
High intensity corridors receive a crash rank based on the number of KAB crashes. The higher number of crashes, the lower the rank. The corridor in the troop, county, or state with the most KAB crashes receives a rank of 1. Corridors which are not considered ‘high intensity’ (that is, there is not both a high crash frequency and high crash rate), receive a rank of 0.
The top 5 roads are defined as the crash corridors that contain both a high CMV crash rate and a high number of KAB CMV crashes. The top 5 roads are ranked based on the number of KAB CMV crashes – where the top roads contain the highest number of crashes.