The San Francisco County Transportation Authority (the Authority) is the transportation planning agency for city and county of San Francisco (Figure 1). The Authority was originally created in 1989 to administer funds from Prop B, a local sales tax for transportation. It currently administers and oversees the delivery of Prop K sales tax program which has superseded the original sales tax measure. The Authority has been called upon to take on a number of additional roles and responsibilities since its establishment. It is the designated Congestion Management Agency (CMA) of San Francisco County and is responsible for developing and maintaining San Francisco's official travel demand model: SF-CHAMP (San Francisco's Chained Activity Modeling Process). Since 1990, the Authority has also served as the San Francisco Program Manager for grants from the Transportation Fund for Clean Air (TFCA).
San Francisco is the 13th largest city in the United States and has a population of 805,235 according to the 2010 decennial census. In the last couple of decades, the population grew by about 80,000 and is expected to grow by more than 100,000 residents over the next few decades. Bounded on three sides by water, the daytime population of the 49-square mile city is close to 1 million. The city's street network is primarily a regular grid system overlapped by dense local and regional transit networks.
To accommodate its projected economic and demographic growth levels, San Francisco needs to trigger a major modal shift from autos to more 'roadway capacity efficient' modes such as bus, bicycling, and walking. This shift would be in line with the city's "transit first" and greenhouse gas reduction policies. To this end, policies which promote such a shift need to be analyzed. Examples of such policies include congestion pricing, a bus rapid transit (BRT) network, and "road diets" in the very densest parts of San Francisco in order to accommodate bicycle and pedestrian throughput. Presently, there are not many reliable and proven modeling tools to make robust predictions of the behavioral response to such policies. The city needs to spend adequate time and resources to develop the next generation of modeling tools capable of analyzing alternative projects that have potentially significant cost savings and long-term benefits.