Economic Adjustment Module (EA). The third module incorporates a regional economic impact model to estimate total impacts on the economy of the study region(s). It starts with a detailed core forecasting model, which projects a baseline projection of each study region's long-term economic growth by industry, given demographic shifts and expected structural changes in the economy over time. 

For each alternative transportation scenario, incremental changes from that baseline are then forecast to reflect business responses to changes in: (a) direct transportation costs -- including time, expense and safety factors, (b) additional productivity scale factors -- associated with expansion of labor and delivery markets, and enhanced network or intermodal connectivity, and (c) additional transportation-contingent economic changes -- including external costs and investment commitments. It also calculates: (d) upstream (indirect) effects on business suppliers, and (e) downstream (induced) effects generated by the spending of added worker wages.  Additional impacts are also estimated for (f) trade flows due to supplier/buyer and import/export linkages, and (g) dynamic adjustments in the structure of the economy over time.  The newest element, which is now being tested, also provides (g) estimated changes in international trade.

The TREDIS-EA module assigns direct impacts from the TC (travel cost) and MA (market access) modules to appropriate economic sectors, adjusts for double-counting, and formats the inputs based on the unique "policy-levers" of the economic model.  In many cases, the business responses are subject to non-linear (threshold) effects, as well as time lags and spatial lags. These impacts are passed - along with project construction spending, O&M spending and contingent development - to the economic model to determine regional increases in employment, output, and income.

Results. The economic adjustment module shows the effect of transportation projects, policies or programs on changes in employment, wage income, business output and GDP (value added). Impacts can be displayed as tables or graphs, with results disaggregated by year, by industry and by study area.  Users can also select to separate short-term spending effects from long-term productivity effects,  or view results from either a local or broader state perspective.  Associated productivity changes that drive this economic growth can also be viewed through a separate benefit-cost report.

Regional Economic Model Options.  The modular aspect of TREDIS® allows it to be used with nearly any form of regional economic model. TREDIS is normally supplied with the DRMR (Dynamic Response, Multi-Regional) macroeconomic impact forecasting system, which incorporates elements of Moody's Analytics® economy.com forecasting and IMPLAN® trade flows within a broader econometric framework.  Those elements are used in the TREDIS framework by agreement with their respective providers.   TREDIS is available for any combination of counties or states in the US, and for any combination of provinces and regions in Canada.  TREDIS can also be used with REMI Policy Insight, Global Insight, REDYN, RIMS-II, and other input-output models.

Note: TREDIS® is a registered trademark of Economic Development Research Group, Inc., IMPLAN® is a registered trademark of Minnesota Implan Group, Inc.