Moving on heavy trucks
The trucking companies truck tables developed from the data were further processed to evaluate the origin and destination of the commodities with respect to the Puget Sound region. These tables were compared to total volumes of truck trips at the external stations and to total internal volumes from the trip generation model. The truck trips for external trips (both internal-external and through trips) compared favorably to the total truck volumes at external stations for heavy trucks. The internal truck trips represent 32% of the total internal heavy truck trips estimated in the trip generation model, so these were used to estimate trip rates for manufacturing and wholesale trade.
The data identifies freight shipping rates for the origin and destination of commodity flows for 30 geographic markets. These regions were associated with appropriate external stations and internal Puget Sound counties to disaggregate these data into traffic analysis zones. Modifications to the original dataset were made to eliminate those commodities that would not likely travel through Puget Sound. The data provided a direct calculation of external (through) trips. These through trips were subtracted from the total heavy truck counts to provide an estimate of internal-external and external-internal trucks at each station. It was assumed that all commodities were moving on heavy trucks. The internal-external and external-internal trucks were distributed to internal zones using the same allocation by industry as the internal truck trips.
Tags: freight shipping rates