Caltrans announced they launched a Pilot to Study Pay-By-Mile Road Charge Concept today.

The idea came about with the help of 5,000 volunteers will test a nine-month program to explore the possibility of replacing the gas tax.

This plan will look into charging drives for the actual miles they drive, as opposed to charging drivers for the amount of gasoline they use.

According to CalTrans, this is "part of an effort to explore options for stemming the loss of dwindling gas tax funds, which have been falling over the past decade as fuel efficiency standards increase and as more people switch to hybrid or electric vehicles."

The loss of funds equates to an unfunded $5.7 billion for maintaining California's state highways. 

For more information, you can watch the latest CalTrans video, here.