Significant Jump in California Driving

Vehicle miles traveled (VMT) in California this year are up "2.6 percent from December through November of 2013 according to estimates from the California Department of Transportation [Caltrans]," writes Phillip Reese, database reporter for The Sacramento Bee. "That’s the largest traffic jump since 2003."

To put that leap into perspective, Reese provides data for prior years:

• Highway traffic in the state grew by an average of 3 percent annually between 1973 and 2003
• 1.4 percent between 2004 and 2007, the pre-recession years
• Between 2007 and 2011 – as the economy tanked – highway traffic fell by 3 percent

California's unemployment rate dropped from 12.5 percent at the height of the recession to 7 percent today, "representing almost a million workers, most of whom commute every weekday," writes Reese.

Kent Hymel, a professor of economics at California State University, Northridge, explains the other driving stimulus. "Probably the biggest reason (for the increase in traffic) is the pretty sharp drop in the price of gasoline,” said Hymel, who has published studies [PDF] on the state’s traffic patterns, writes Reese. “It was over $4 a gallon; now, it is down to about $2.60,” adds Hymel.

The increase in driving is expected to have a negative effect on the state's tough greenhouse gas emission reduction goals mandated by AB 32, notwithstanding improved fuel efficiency and an increase in electric vehicles.

Vehicle traffic is “a major contributor” to greenhouse gases, accounting for about 30 percent of the state’s emissions, said Kanok Boriboonsomsin, an associate research engineer at the Center for Environmental Research and Technology at the University of California, Riverside.

Hat tip to The AASHTO Daily Transportation Update