Regional Traffic Counts
Gulf Regional Planning Commission (GRPC) works cooperatively with the Mississippi Department of Transportation (MDOT) to collect traffic count data in Hancock, Harrison, and Jackson counties. Traffic count data for the Gulf Coast is collected on a three (3) year cyclical basis. Due to each of the 1,300 count sites being collected every third year, estimates are developed for the interim years in which traffic count data is not collected.
Traffic count data is presented as an Annual Average Daily Traffic (AADT) count. This means that the raw data is collected over a 48-hour period, and traffic adjustment factors are applied to that data to arrive at an “annual” average daily traffic count total. The AADT factors take into consideration high and low seasonal and daily traffic patterns to arrive at a more representative “annual” traffic count for the selected roadway segment.
In addition to the regularly scheduled traffic counts, numerous other special counts will be taken to support specific transportation planning projects or at the request of local governments for various reasons. Occasionally, at the request of local jurisdictions and other special circumstances, speed counts are taken, providing various reports on vehicular speed, time of day, etc. Vehicle classification counts can also be taken, wherein the traffic volume is reported in various formats by the type of vehicle, including cars, buses, various-sized trucks, etc.