By approving a half-cent sales tax increase on Tuesday, Charleston County voters underscored just how woeful the area’s transportation situation has become. County Council must take every necessary step to assure that the $2.1 billion will be used toward the best possible ends, as it tackles the gridlock dogging every part of the metropolitan area.

The needs are indisputable, and so is the fact that the state Department of Transportation hasn’t lived up to its responsibilities. In part, that is because state legislators haven’t been willing to increase the gas tax to provide the necessary revenue for South Carolina’s mammoth transportation needs.

And so Charleston County Council decided to go to the voters once again, as it did in 2004, asking them to approve another half-cent tax increase to tackle a traffic situation that just keeps getting worse. The challenge is evident to motorists whenever they venture out; that is why the referendum was approved.

Certainly, it wasn’t because of County Council’s adeptness in managing the run-up to the referendum. It wavered over whether to bring the controversial I-526 extension into the list of projects to be financed by the tax addition, and finally decided not to. It was a wise decision.

Not long after that, however, Council Chairman Elliott Summey joined Charleston Mayor John Tecklenburg in a joint effort to do what Council had decided against by proposing new projects to induce the reconsideration of I-526 by the State Infrastructure Bank. The SIB wasn’t biting, and the plan was thankfully shelved.

Even so, prospects for the referendum were hardly auspicious when voters went to the polls. While it had the backing of local governments, the business community and public transit supporters, it was opposed by two influential groups — the Coastal Conservation League and the League of Women Voters.

Again, that it passed speaks to the severity of the problem, and the potential for improvements that $2.1 billion offers to the community in road improvements and mass transit. Particularly encouraging are plans for a bus rapid transit system serving Summerville, North Charleston and Charleston. It could provide a different kind of relief to commuters now stuck in traffic on I-26 during rush hour. The referendum also will provide $210 million for the greenbelt program designed primarily to forestall the ill effects of urban sprawl.

But most of the funding will be used for road projects, and the first responsibility of County Council, soon to choose a new chairman, is to provide all necessary assurances that the road money will be spent only for priority projects to relieve gridlock, such as improvements to Main Road on Johns Island and West Ashley, and Hwy. 41 in Mount Pleasant.

Meanwhile, pressure needs to be exerted for a permanent legislative solution to the South Carolina’s transportation problems. And as South Carolina’s fastest growing area, the Charleston metropolitan area deserves the state’s transportation focus.