Increases in vehicle ownership enlighten southern California’s decrease in public transit ridership

By Logan Dredske

Although national transit ridership has remained steady over the last decade, ridership in Southern California has been on the decline (Figure 1). The Southern California Association of Governments (SCAG) released a report offering explanations for why transit ridership has been decreasing in the six counties participating in the association.

Figure 1. Transit trips per capita in southern California.

While transit investments in both the U.S. and California rose almost 50 percent between 2000 and 2015, passenger boardings per vehicle has fallen 5 percent in California and 14 percent in the SCAG region.

SCAG analyzed likely causes of decreased ridership such as changes in transit service and fares, fuel prices, transportation network companies, and neighborhood changes, none of which demonstrated a significant impact on the use of transit. However, when the team analyzed private vehicle ownership, they discovered it to be the largest factor in the decreased use of public transit.

Individuals living in an urban setting who do not own a vehicle are common public transit users. From 1990 to 2000 the SCAG region added 0.25 vehicles per new resident and from 2000 to 2015 the region added 0.95 vehicles per new resident. When analyzing the share of zero-vehicle households in the region from 2000 to 2015, the results are even more telling:

  • 30 percent decrease in zero-vehicle households,
  • 42 percent decrease in zero-vehicle households with foreign-born residents, and
  • 66 percent decrease in zero-vehicle households with foreign-born residents from Mexico.

Other factors that the research team explored such as income, race, and age proved to be determinants of transit use, but largely because they relate to vehicle ownership. The desire for people to drive in Southern California is in part motivated by the existing built environment. “Much of the region’s built environment is designed to accommodate the presence of private vehicles and to punish their absence. Extensive street and freeway networks link free parking spaces at the origin and destination of most trips. Driving is relatively easy, while moving around by means other than driving is not. These circumstances give people strong economic and social incentives to acquire cars, and once they have cars to drive more and ride transit less,” explained the authors.

Logan Dredske is a Project Assistant at SSTI.