Climate Science and Policy

Transportation is the largest contributor to GHG emissions in San Diego. To reduce GHG emissions from the transportation sector, total vehicle miles traveled (VMT) must be reduced and average vehicle occupancy (AVO) has to be increased. This study assesses flexible transit as a solution to tackle VMT and AVO in San Diego. The study analyzed travel patterns and created potential vanpool routes for replacing driving alone work trips. The potential routes and route score can be used to prioritize and target groups of individuals who are suitable for the vanpool program by the geographic area of home and workplace. Based on the result, the current SANDAG Vanpool program has an opportunity to expand the program and increase the number of participants. Potential benefits of vanpools are estimated to have a total daily reduction of up to 50,392 vehicles, 421,761 VMT, and 143.06 tons of CO2. Compared to scenarios for a radical expansion of legacy forms of fixed-route transit, the flexible transit deployment would require significantly less operational subsidy, due in large part to unpaid drivers, and radically less expense to the public for hard infrastructure investments. Expanding flexible transit thus makes economic sense. Flexible-transit will also be much more likely to attract new transit users given a preferred travel experience with a straight point to point transport and absent mode changes or transfers for riders that have origins and destinations outside of transit adjacent development. This study has shown that flexible transit has the potential to be a solution to both transportation and GHG emissions problems in San Diego.