Emissions Analysis Techniques for TCMs
Overview - The ECO (Employee Commute Options) software suite was developed for the Oregon Department of Environmental Quality (DEQ) to help Portland area employers comply with ECO rules. The ECO Software is based closely on the "TDM" model developed for the South Coast Air Quality Management District (SCAQMD) to support the Regulation XV program in California.
Strategies Addressed - Improved transit; HOV lanes; carpooling and vanpooling promotion; employer-based TDM; bicycle and pedestrian facilities; telecommute and work hour strategies; pricing and subsidies.
Methodology - The ECO software is intended for application at the level of single or multiple employer sites. Strategies are evaluated using a "pivot-point" mode choice model, similar to the FHWA TDM Evaluation Model. In addition to time and cost strategies, the mode choice model includes coefficients for a number of other strategies such as provision of bicycle facilities and various ridesharing incentives. The coefficients were developed from the Regulation XV employer dataset in Southern California. The model makes adjustments to effectiveness based on the extent of marketing and awareness programs. The software includes additional features, notably a module for managing employer surveys and data, and a module for tracking program participation.
Data Requirements - Baseline mode shares, other travel characteristics, and characteristics of the employment sites; provision of and eligibility for various programs; amount of costs or subsidies for various modes.
Outputs - Changes in modal share, vehicle-trips, VMT, average vehicle occupancy, and ridership.
Level of Effort - The ECO software is Windows-based and easy-to-use. However, it would require customization to develop appropriate model coefficients for local application. Also, it requires survey data on baseline employee travel characteristics at affected sites.
Advantages - The logit-based pivot point mode choice approach is theoretically sound, consistent with common practice in travel demand forecasting, and capable of analyzing the joint impacts of multiple strategies. The mode choice model includes a range of employer-based strategies in addition to time and cost-based strategies. The awareness submodel provides a unique adjustment for marketing and promotional efforts.
Limitations - The software does not estimate emissions benefits directly, so the user must apply VMT and/or trip-based emission factors. Many of the default coefficients and data were derived from a dataset in Southern California and their validity in other areas has not been tested. The software would need to be customized for use in other areas.
Source/Availability - The Regulation XV software was developed for SCAQMD by COMSIS corporation. The ECO software was developed for Portland DEQ in 1998 by Cambridge Systematics, Inc. For more information, contact Susan Christensen (503-229-5518) or Sandra Hall (503-229-6154) in the Oregon Department of Environmental Quality (2020 SW Fourth Avenue; Portland OR 97201); or Steve Decker at Cambridge Systematics (510-873-8700).