SANDAG has developed an innovative benefit cost analysis tool that incorporates a diverse range of sources of benefits and costs, exploits the detailed information produced by SANDAG’s activity-based travel demand model system, and provides new insights into which regional travelers receive the benefits or bear the burdens of regional plan investments and policies. The tool interacts directly with SANDAG’s model input and output database.
Sources of benefits and costs include traditional elements such as travel times for regional travelers, freight and commercial vehicles, auto ownership and operating costs, emissions estimates, and collisions. In addition, the benefit cost analysis tool also monetizes benefits and costs associated with changes in levels of regional residents’ physical activity as well as changes in travel time reliability. To the greatest extent possible the tool is applied at the level of disaggregate individual trips, which provides greater analytic precision and flexibility. For example, the tool can provide detailed assessments of environmental justice effects while minimizing aggregation bias, and communities of concern can be flexibly defined using any attribute present in the synthetic population that is input to the activity-based model system. In addition, while the model uses a uniform value of time across all travelers for monetizing travel time savings, it can also calculates a trip-specific value of time reflective of household income, tour purpose, and occupancy that can be used to provide more detailed insights into the benefits and burdens of the plan alternatives.
The benefit cost analysis tool is embedded within SANDAG’s larger integrated activity-based travel demand and land use model framework, and interacts directly with the agency’s regional model database. Users are able to view and modify benefit cost analysis assumptions, and can refine the reporting of outputs to provide summaries for specific travel sub-markets, sociodemographic groups, or geographic subareas. This presentation will provide an overview of benefit cost analysis principles, describe key inputs and assumptions used in the benefit cost analysis tool, and provide examples and illustrations of tool reports and summaries.