Select a question topic:
Question: Your documentation mentions the stages of the transportation planning process. Where can I find a definition of the transportation planning process?
Answer: TREDIS uses publicly available guidelines to define the transportation planning process. The Transportation Planning Process Briefing Book provided by the U.S. Department of Transportation and Federal Highway Administration is one such example. This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. You may review the document here: http://www.fhwa.dot.gov/planning/publications/briefing_book/part01.cfm#Toc420927559
Question: Is TREDIS able to provide economic impact/benefit analysis for programs that increase the diversity of modes in that system (pedestrians, bikes, transit)?
Answer: Yes. Any change in diversity of modes can be analyzed with TREDIS by specifying: (1) changes in the modes available, (2) the extent of the use of each mode, (3) the change in travel time, distance, cost or reliability for those using each relevant mode, and (4) other environmental or social benefits not otherwise noted. TREDIS also includes data on the energy use and environmental effects of pedestrian and walking modes, as well as the motorized modes.
Question: Are there TREDIS inputs for parking? For example, a road widening may reduce on-street parking.
Answer: TREDIS makes it possible to assess the impact of a scenario that changes parking capacity or cost. To do so, the analyst must specify how this scenario would affect one or more of the following factors: parking fee (per trip cost), in-vehicle travel time (including time looking for a parking spot), walking time (out of vehicle or buffer time allowance), and/or car/transit mode split.
Question: How is it possible for a scenario to include new development and yet the auto trips and VMT (vehicle miles of travel) go down anyway?
Answer: This can occur if the scenario has a pattern of development density and spatial location that supports transit-oriented development, leading to a shift from auto to transit trips. This type of situation occurred when TREDIS was used to model the impact of transit oriented land use for the San Francisco area.
Question: Does TREDIS allow for the benefit of transit-oriented development in existing areas, as opposed to new highway-oriented development in greenfield areas?
Answer: TREDIS was built to uniformly cover all modes of transportation, and their interactions without bias towards or away from any particular mode of travel. It is up to the analyst using TREDIS to provide information on the change in travel and access characteristics that would be expected from any given type of transportation investment, such as transit-oriented development. TREDIS does include several features that will help provide a more balanced representation of transit benefits. This includes capabilities to incorporate analysis of the productivity benefits from enhanced job market access and effective density or agglomeration effects, as well as decreases in pollution emissions and reductions in traffic congestion growth.
Question: Does TREDIS allow for the use of TDM - travel demand management actions (such as VMT fees, congestion pricing, transit & other modal options, etc.) to determine their viability as alternatives to proposed highway projects?
Answer: TREDIS can be used to assess the net benefits or economic impacts of TDM actions, as long as the analyst develops measures of the extent to which those actions bring about changes in traffic volumes, speeds, costs or other travel characteristics.
Question: Can TREDIS assess changes in energy efficiency as investment criteria?
Answer: TREDIS includes assumptions about vehicle fuel economy as an element of operating cost. Those assumptions can be modified by analysts to assess the impact of a transportation policy or program affecting energy efficiency.
Question: Can TREDIS evaluate infrastructure preservation projects and compare them to capacity projects?
Answer: Yes, can be used to assess both types of projects. Both Michigan DOT and Kansas DOT have published studies using TREDIS to assess the economic impact of investing in infrastructure preservation, compared to the scenario of letting infrastructure decline over time in its performance and use. The ASCE national study of infrastructure investment similarly used TREDIS to address those same types of scenarios at a national scale.
Question: Is the analysis of ITS (intelligent transportation systems) possible with TREDIS?
Answer: Yes, TREDIS can model the impacts of ITS or any other investments that lead to changes in travel times, reliability , capacity, etc. All of these changes can occur with ITS-type investments in actions such as traveler information systems, synchronized signal timing, dynamic control of transit vehicles, etc.
Question: Do current federal programs require economic analysis of the type done by TREDIS? How about future authorization bills?
Answer: Current USDOT discretionary grant programs including FRA rail grants, FAA capital investment grants and TIGER grants all require some form of benefit-cost analysis to be done, and some (such as the TIGER program) also asks for analysis of local economic development impacts. New 2012 federal transportation authorization puts a focus on projects of national significance, which also depends on economic impact factors.
Question: Will the next transportation authorization require analysis like the examples shown in today’s policy webinar?
Answer: There is a very good chance that economic impact analyses will be required. There have been two blue ribbon commissions that have required impact analyses, as well as a bi-partisan transportation commission. Much of the transportation community, including groups such as AASHTO and AMPO, have already given recognition to the role and importance of economic development considerations.
Question: Has anyone looked at the impacts of not investing in preservation?
Answer: Yes, Kansas DOT used TREDIS examine at what would likely happen to their economy if they let bridges and pavement deteriorate, and Michigan also used TREDIS to assess the impact of reducing the amount spent on preservation
Question: Does TREDIS treat roadway pricing revenue as a benefit or a cost?
Answer: In the benefit-cost module of TREDIS, tolls and other road pricing schemes are all treated as transfers of money between parties (payments from travelers to facility or service operators), and hence by themselves they are neither a cost nor a benefit to society. However, roadway pricing can lead to other travel efficiencies which can directly affect benefit-cost results. In addition, TREDIS has a regional economic impact forecasting module, and that can show effects of roadway pricing on raising changing local business operating costs and thus the attractiveness of affected areas for business growth.