The purpose of this project is to describe the character (profiles) of the truck traffic that travels a wide selection of highways in North Carolina. Such information can be used to evaluate a variety of issues in planning, design, operations and policy. The research approach used a variety of data sources including: NCDOT WIM data, LTPP data, special 48-hour classification counts at selected urban and rural highways (especially low volume State Route (SR) highways), all overweight truck permits for year 2006, and NC truck network model estimates validated at the R2 = 0.92 level by 472 ground counts. Analysis of the data yielded the following products: (1) a review of current truck flow estimation processes in North Carolina; (2) tabular information regarding vehicle weights and distances traveled on specific road classes; (3) a database that includes truck traffic profiles for urban and rural areas by NC region, vehicle classifications, weights, trip lengths, and highway types; (4) permitted overweight truck traffic profiles on three major interstates; (5) frequency of use of permitted overweight trucks on the top 10 highways by functional classification; and (6) truck traffic on a wide selection of State Routes near truck generators. Overall the research provided valuable information for pavement design, transportation planning and policy. Key recommendations are (a) NC DOT needs to keep enhancing its truck network model; it is an excellent method way to estimate VMT for the state and forecast rural truck raffic. Relying on the 48-hour short counts, and statistical inference, is mandated and helpful. (b) NC DOT should continue its quality control efforts related to the WIM datasets. And (c) It would be highly advantageous if the overweight permitting database was more regimented in the way it records the routes used by overweight trucks. Using GIS methods would be very helpful to plan and evaluate overweight permitted routes.
