GOV. ROBERT F. McDONNELL has done a good job with the small stuff to improve Virginia’s ailing, severely underfunded network of roads, rails and bridges. But when will he do the big things?

That’s the question after Mr. McDonnell’s latest transportation announcement — of federal approval for a potential, and very modest, measure to install tolls on Interstate 95 south of Richmond. If the state goes ahead with the plan and the feds continue to give the green light, it might, starting in 2014 or so, yield $50 million a year for improvements along the interstate corridor in the southern part of the state.

Excuse us for being underwhelmed. A $50 million drop in the bucket — in terms of revenue, the equivalent of adding one penny per gallon to the state’s absurdly low gas tax — is not going to noticeably improve the deteriorating driving conditions that millions of Virginians face every day.

The I-95 announcement does fulfill a campaign promise, and we give Mr. McDonnell credit for that. We also give him credit for having been honest about the shortcomings of the steps he has taken to date.

Those steps include an audit of the state transportation department, which determined that officials had been too conservative in holding hundreds of millions of dollars in reserve that could be better spent on building and maintaining roads now; an acceleration of the schedule for state bond sales that will get several billion dollars out the door, to be spent on construction projects, sooner rather than later; and sound appointments to key positions, including, in recent days, Jim Dyke, a former chairman of the Greater Washington Board of Trade, as the state’s representative on the board of Metro.

Those are all fine and sensible things. But as Mr. McDonnell himself has acknowledged, they don’t go far enough. Specifically, they do nothing to address the massive structural shortfall in funding for transportation in the years beyond Mr. McDonnell’s governorship, which ends just over two years from now.

To get an idea of how severe the shortage of sustainable revenue has become, take a look at state-generated funding for construction. In 2004, less than 10 percent of the state’s transportation construction budget was diverted for maintenance needs. Today the condition of Virginia’s roads, rails and bridges is so deplorable, and is continuing to deteriorate so fast, that more than 80 percent of funds earmarked for construction each year is diverted to fill potholes, shore up bridges and fix rail lines. Without new and reliable funding dedicated to transportation, that will be true for the foreseeable future.

Borrowing money through the bond market makes sense as a stopgap; it does nothing to resolve the underfunding problem, and it burdens the state with debt. Privatizing the state’s liquor stores, which Mr. McDonnell has tried and so far failed to do, would also produce a one-time windfall, not a lasting solution.

Mr. McDonnell’s transportation secretary, Sean T. Connaughton, this week tried to explain away the staggering traffic — much of it in Northern Virginia — that has given the Washington area the dubious distinction of being No. 1 in the nation for gridlock.

The bad news is actually good news, enthused Mr. Connaughton, since congestion is a symptom of prosperity. We take his point, but as Mr. Connaughton well knows, the charm of traffic jams has its perils. Firms and their employees are becoming increasingly reluctant to locate in a place where drivers on average spend more than 74 hours annually sitting in traffic — the equivalent of more than three days. That’s worse than Chicago, Los Angeles or New York. And the problem will only intensify as the Washington region’s population continues to grow, as is projected.

If Mr. McDonnell is serious about fixing the transportation funding problem in Virginia, there are no magic tricks or shortcuts. He has two choices, both politically painful.

One is to increase taxes — an obvious one is the gas tax, which, due to more fuel-efficient cars, produces less than half the revenue it did when last raised in 1986 — and dedicate the income to transportation. The other is to raid the state budget and siphon funds from schools, public safety and public health.

Virginia’s budget is already lean, and we doubt the governor can rob schools, police and the modest safety-net programs to pay for roads without harming the state’s well-being. Taxes are what get roads built. Mr. McDonnell, who prides himself on being a problem-solver, should face up to that reality.