

Imagine how much smoother the traffic filled roads could be! (Photo by Kevork Djansezian/Getty Images)

Gas guzzlers, like SUVs, have gone out of style with gas-sippers, Priuses and electric cars increasingly taking their place. That's great news for the environment but bad news for Caltrans, which relies on a gas tax to maintain our roads.

So starting later this year, Caltrans will be introducing a pilot program to determine whether or not the state gas tax is out of date. Instead of taxing people by the gallon for gasoline, California could instead tax people by number of miles driven.

California currently adds a 36-cent tax to the cost of each gallon of gas sold in the state, but today we're buying fewer gallons. Aside from hybrids and electrics, even ordinary cars hitting the road in 2016 are vastly more fuel efficient than cars in the 1930s, when gas taxes were originally passed. If we all switched to Priuses, the state couldn't afford to pave the roads. As it stands, the state's fuel tax raises $2.3 billion annually, only a fraction of the $8 billion it costs Caltrans to maintain and pave roads, according to the Los Angeles Times. (And we could use some more funding: California's roads are the worst in the nation, according to a 2015 study by TRIP, a national transportation research group.)

To figure out how to close the gap, Caltrans is going to experiment with taxes based on total miles driven, dubbed the Road Charge Pilot Program, instead of a tax based on fuel consumption. This summer, the agency will start collecting data on the driving habits of 5,000 volunteers who drive all sorts of vehicles. The program will last for nine months, during which different mileage tracking methods will be experimented with.

The rationale goes, roughly, that hybrid and electric cars use the roads just as much as their less environmentally conscious predecessors. A heavy Tesla contributes just as much wear and tear to the road as a Ford Explorer, based on their weight, but the Tesla owner contributes nothing to the state’s road fund through gas-taxes.

In practice, a tax levied based on vehicle miles is challenging. Privacy groups express worries that enforcement will require GPS tracking of people’s driving habits, exposing the locations of homes and work. But the idea has been successfully implemented in some European countries like Germany and the Czech Republic. Oregon also began a trial in 2013 with 5,000 of its own drivers, to figure out whether or not the state could pave its roads more smoothly if they tax by the mile.

If you're interested in being one of the lucky 5,000, you can volunteer at the California Department of Transportation's website.