CDM Smith developed its National Interstate Tolling Analysis Tool (NITAT) for the U.S. Federal Highway Administration (FHWA) as part of a wider interstate tolling study. This computer traffic model, the only one of its kind, is a sketch-level planning resource for modelling potential traffic and revenue impacts of tolling segments of the toll-free interstate system that are currently toll-free. NITAT allows users with no modelling background to run scenarios  for the entire interstate system, for 48 individual states and for most other major highways and tolled facilities. It disaggregates more than 3,000 counties and urban areas across the United States into nearly 7,500 traffic zones and incorporates National Bridge Inventory data for major bridges on the interstate system. The model can compare different options for toll rates, deliver separate analyses for car and truck impacts, estimate capital and operating costs associated with toll collection, and assess impacts on network performance, safety and fuel consumption. One model run found that, if all-electronic tolls in the range of $0.04 per mile for cars and $0.10 per mile for trucks were added to the entire non-tolled interstate system, average annual revenue would exceed $46 billion in 2011 dollars.