Using national freight data at the local level is challenging due to the high level of aggregation, its proprietary nature and the need to apply proxy factors to allocate freight for system planning. Planning factors used in freight system analysis must be capable of describing the freight generation and attraction characteristics of the region. Employment as a planning factor has come under scrutiny due to the inability of this factor to accurately estimate the effect of productivity improvements made by a company to increase production without increasing employment. Economic data from different sources can be used to allocate freight volume into smaller zones from freight traffic volumes provided by national databases and this output can be used to model freight and integrate freight into existing transportation planning activities at the state and local level.

The Development of an Integrated Freight Planning Framework