To explore the idea of replacing the gas tax with a road use charge, the state Department of Transportation is sending individual “driving reports” to thousands of vehicle owners and asking for feedback.

They will help drivers compare the potential cost of paying by the mile or by the gallon for their use of the roads. The effort is part of federally funded research by the state on the feasibility of funding road maintenance with a per-mile road use charge instead of taxing gasoline.

As cars become more fuel- efficient and some rely on electricity, drivers are buying less gasoline across the country. As a result, communities are collecting less money through the gas tax to pay for road and bridge maintenance. But the cost of such roadwork keeps rising.

The driving reports are the latest phase of a three-year study to consider whether it would be fairer and more consistent to switch to a road-use charge to assess an individual’s use of the transportation system.

“The driving report will start arriving in mailboxes in November for most car owners who recently had their annual safety inspection,” said Jade Butay, director of the Department of Transportation. “It will compare what they paid in gas taxes over the last year to what a road usage charge could cost for the same vehicle and mileage.”

The customized reports are strictly educational — they are not bills. They ask for feedback from owners through a short online survey. The first reports will be mailed to 50,000 households this month, ramping up to hundreds of thousands over the course of next year.

With the gas tax, some drivers pay more because they can’t afford to upgrade their vehicles to more fuel- efficient ones. Rural residents and low-income drivers can be hit especially hard. The department will use mileage records from recent vehicle inspections to estimate gas taxes, depending on vehicle make and model.

The research is the latest phase of a three-year study that included 14 public meetings across the state and includes a demonstration project next year involving volunteers. Ultimately, the department will provide a report to the Legislature and governor, who would decide whether to adopt a road-use charge to replace the gas tax.

“Even if the research indicates the RUC is a feasible alternative to the gas tax, discussions with states who have been working on this for many years indicate that establishment of a new system could take up to 10 years,” said Ed Sniffen, deputy director of the Transportation Department’s Highways Division. “We look forward to hearing from the public on their thoughts on the RUC and how we can improve our service to them.”

To learn more, see sample “driving reports” or sign up for email newsletters, visit www.hiruc.org.