VIRGINIA REPUBLICANS, having won control of the state Senate and, with it, power over all major levers of government, are now responsible for fixing the commonwealth’s scandalously neglected transportation network. Their dilemma is how to hold the line on new taxes, as most have pledged to do, while devising a solution to a problem that will cost — at a bare minimum — $1.6 billion annually for at least the next few years.

Any rational policy would start with raising the gas tax, which Virginia hasn’t touched in a quarter century. Inflation has eroded the revenue it yields, leaving the state, despite its relative wealth, with a pittance to build roads. Despite that, the GOP refuses to revisit the issue.

As Bob Chase, a transportation analyst, wrote recently for the University of Virginia’s Cooper Center for Public Service, since 1986 Virginia has added 1.5 million licensed drivers, 2 million people and 2.9 million registered vehicles — but not a dime in new, long-term transportation funding. If utilities were similarly ignored, Virginians would lack heat, electricity and water. “The basic problem,” says Mr. Chase, “is the people of Virginia are not being asked to pay for the transportation they are using.”

Gov. Robert F. McDonnell (R) has streamlined the Virginia Department of Transportation and accelerated borrowing to generate spending on roads now. But as he admits, neither of those provides a long-term solution.

The most severe problem is in Northern Virginia, particularly the badly congested jurisdictions of Fairfax, Prince William and Loudoun counties, where almost one in four Virginians live. State officials say that they can no longer afford to maintain local roads there, as they have for the better part of a century. They are floating the idea of transferring responsibility for upkeep to the counties, along with state funding to do the job.

In theory it’s a fine idea; local governments take care of neighborhood roads in all but a few states, as do cities in Virginia (and, for historical reasons, Arlington County). The problem is that the state funding formula, which favors cities and rural counties, is a terrible deal for large, congested counties. It would stick them with annual maintenance bills in the tens or hundreds of millions of dollars.

Clearly, new rules — and dollars — are required. If the state is going to transfer responsibility for maintenance to the counties, it must ensure they have the money to do the job. That might mean adjusting Richmond’s formula so that urbanized counties such as Fairfax are funded like cities. It might mean the state would levy a surtax to help maintain local roads in Northern Virginia. Or it might mean permitting Northern Virginia to levy new taxes itself — but without putting the question on the ballot in a referendum, which would politicize a critical issue.

Mr. McDonnell has rightly called the transportation problem a crisis. He must put ideology aside and push for a major cash infusion, without raiding funds for other core government functions like education or sticking local officials with unfair financial or political burdens. If he manages that, his will be a landmark governorship.