The state’s healthy budget surplus means that South Carolina’s economy is picking up, and also that some of its deteriorating bridges will actually get funds for repairs. Good news on both fronts.

While the Legislature wasn’t willing to approve a long-overdue hike in the state gas tax last session, it did provide extra funding for road and bridge projects, including $50 million for bridges, assuming a budget surplus.

The need is apparent, since the state Department of Transportation lists $2.9 billion in bridge work that needs be done over the next 20 years.

The unsatisfactory state of South Carolina’s bridges was detailed in the annual AAA Carolinas report. Twenty-two percent of the state’s 8,383 bridges are listed as substandard. That rate sharply rises in Charleston County to 33 percent — the highest in the state. Indeed, seven of the state’s 20 most substandard bridges are in Charleston County, according to AAA. The worst local rankings were for the twin drawbridges over the Ashley River.

The DOT lists 886 of its bridges as structurally deficient, and 777 as functionally obsolete.

But that doesn’t mean they are an immediate safety hazard. “Structurally deficient” means a bridge in is in relatively poor physical condition or is inadequate to handle truck weight. “Functionally obsolete” refers to older bridges that aren’t designed to handle current traffic.

DOT state bridge maintenance engineer Lee Floyd has criticized AAA for putting out the annual ranking of bad bridges.

“It’s a just a formula that they invented themselves,” Mr. Floyd said. “It has no application in the real world. They create a lot of unnecessary angst.”

But considering the funding inadequacy, there ought to be more than a little angst about the condition of the state’s bridges. Publicity like the AAA list can only encourage the Legislature to provide extra resources.

Gov. Nikki Haley recommended dedicating new general fund revenues for road and bridge work, and to its credit, the Legislature followed her lead.

Lawmakers should continue to provide additional annual support until the funding gap is closed.

Dedicated sources of revenue are needed, and the best place to get more is by an increase in the state gas tax. It allows those who use roads and bridges to pay for their maintenance and construction. And since about 30 percent of that tax revenue comes from out-of- state motorists and truckers, it’s a good deal for the state’s taxpayers.

South Carolina’s gas tax, one of the lowest in the nation, hasn’t been raised in 26 years, and at present fails to provide the necessary support to the overly large DOT highway system. But again, the Legislature has been unwilling to raise the tax, even considering the desperate need.

The extra $50 million will take care of about 50 bridges. It’s a welcome addition to the DOT’s ongoing program. But with more than 1,600 substandard bridges, there’s plenty more to do for the foreseeable future.

Clearly, the Legislature needs to pick up the pace.