SACRAMENTO — California is looking for 5,000 volunteers to help it test a road fee based on the miles driven that could replace the gas tax as the source of money for road repairs and maintenance.

The test drivers — who will try a range of mileage reporting options — will pay no real money.

Data gleaned from the tests will be “vital in fine-tuning the … program that could eventually tie highway funding with road usage rather than gas tax proceeds,” Caltrans said in a news release.

The horde of volunteers is meant to reflect the “vast geographic and socioeconomic diversity of the state,” the state agency said Friday.

Volunteers will have the choice of submitting mock payments via mail or a website.

The volunteer drivers will test mileage recording methods such as time or mileage permits, odometer charges, automatic remote charging with and without location information.

Time permits would allow drivers to use state roads for a specified period of time, and a mileage permit would be a prepaid use. Odometer charges could be a driver’s self-reported mileage, which the state could randomly verify.

Automatic charging would rely on vehicles equipped with devices to report mileage, resulting in bills being sent to drivers.

Location information might be used to exempt miles driven on private roads or out of state.

Fluctuating gas prices, increased use of hybrid and electric vehicles and overall improvements in new vehicle fuel economy have undercut the state’s reliance on the fuel tax.

“The gas tax is outdated and no longer capable of meeting all of our future transportation revenue needs,” said Will Kempton, executive director of the California Transportation Commission.

Caltrans said the state fuel excise tax funds $2.3 billion of work annually, leaving $5.7 billion in unfunded repairs each year.

Information and volunteer enrollment is available at www.CaliforniaRoadChargePilot.com.

Gov. Brown signed legislation in 2014 to set up the pilot program.

Contact Andrew McGall at 925-945-4703. Follow him at twitter.com/AndrewMcGall