Hawaii’s roads carry more electric vehicles these days, and while it may be a blessing for the environment, it’s a curse on gas tax revenues.

And since gas taxes pay for road maintenance, the state Department of Transportation has rightly been concerned about losing funds needed to keep our highways in good condition.

The proposed solution: Replace the gas tax with a road use charge (RUC). That way, all vehicles — gas or electric, gas sippers or gas guzzlers, Teslas or Toyotas — would contribute in a more equitable way. Drivers would pay based on the number of miles driven, not by the amount of gas consumed.

The state has been moving deliberately in testing the waters. The latest step in the state’s three-year study has been to mail out “driving reports” to thousands of Hawaii drivers that provide a comparison of what they paid in gas taxes compared to a potential road usage charge. Vehicle safety inspections provide the data on total miles driven. Drivers are asked to fill out a survey.

The proposed change sounds good, but like anything related to taxes, it’s complicated. Roads need money to be maintained. At the same time, EVs and fuel-efficient cars are environmentally friendly options. Public policy should encourage both. Would eliminating the gas tax make it easier to buy a gas guzzler? There’s also the question of how rental car-driving tourists would pay.

One thing’s for sure: The RUC should be a replacement, not an addition. It should collect roughly the equivalent of the current gas tax, with the burden spread more evenly among all road users.