The use of national freight data at the local level is challenging due to the high level of aggregation and because freight data is proprietary.  Many national freight databases aggregate information to the individual states or major communities.  Most methods of utilizing freight data depend on applying proxy factors to allocate the freight to the system.   The planning factors used in freight system analysis must be capable of describing the freight generation and attraction characteristics of the region.  The use of employment as a planning factor has come under scrutiny mainly due to the inability of the factor to accurately estimate the effect of productivity improvements made by a company to increase production without increasing employment.  This research has shown that local economic data from many different sources can successfully be used to allocate freight volume into smaller zones from the future freight traffic volumes provided by highly aggregated national databases.  The output of this effort is used as input to the modeling of freight, and the integration of that freight into existing transportation planning and modeling activities at the state and local level.  This has been accomplished in Alabama at the statewide and metropolitan planning organization level, resulting in validated transportation models that integrate freight into the planning activity.  The methodology described in this paper can easily be replicated by other states and metropolitan planning organizations.

Development of a Freight Database for Use in Allocating Freight Traffic to Sub-State Traffic Zones