US Department of Transportation, Freight Web Site, www.dot.gov/freight  2006

Chapter 7.3 INCIDENCE AND EQUITY OF BENEFITS AND COSTS

Multimodal Benefit/Cost Analysis is a form of standard benefit/cost analysis in which the benefits and the costs are accounted separately for each mode. That approach can allow for distinction between passenger and freight travel benefits when transportation facilities are shared by both groups. It can also assist in distinguishing benefits associated with privately owned modal facilities (e.g., most rail facilities) from those associated with publicly owned modal facilities (e.g., most highway facilities). Systems such as TransDec (Transportation Decision Analysis Software) and TREDIS (Transportation Economic Development Impact System) accomplish these goals. ... Both systems are also noteworthy for their ability to also cover accessibility and connectivity benefits and economic growth impacts as well as implications of cost savings for existing freight flow patterns.

TREDIS is also described in the Chapter 10 Toolbox of the Guide cited above.