How Does it Work? TREDIS is comprised of modules that work together to determine the full economic impact of transportation projects. Any single module or combination of modules may be used independently of the others.

Travel Cost Module. The first module translates changes in traffic volumes, travel times and accidents into direct cost savings that accrue to household and industry sector of the economy.

Market Access Module. The second module translates changes in market access and intermodal connectivity into effects on agglomeration, dispersion and scale economies for industry sectors.

Economic Adjustment Module. The third module incorporates a dynamic, multi- regional economic impact model to estimate long-term impacts on employment and income growth over time.

Benefit-Cost Module. The fourth module of TREDIS calculates the net present value of project benefits and costs from the differing perspectives of federal, state and local agencies.

Tax and Finance Module. An optional module calculates the local, state & federal tax revenue impacts of projects, as well as public & private economic impacts of tax, toll and pricing scenarios.

Freight and Trade Module. An optional module shows impacts on economic flows ($) and commodity (tonnage & vehicle) flows to, from and within study area. Details are shown by mode and industry, along with employment supported by traded products.

The TREDIS modeling framework is designed as a seamless tool to analyze the economic impact of transportation projects “from scratch.” However, it can also be “broken apart” so that each of the modules may be used individually, in any combination with one another, or in conjunction with a user’s in-house substitute. For example, a user may already have estimated the direct effects of a transportation policy, and is only interested in the market access effects and secondary impacts. In this case, the Travel Cost Response and Benefit/Cost Accounting modules may be circumvented.