SEATTLE -- High gas and parking prices are convincing people to drive less. Statewide, traffic volumes are down by two percent.

That may not sound like much, but it's enough to slow down the state Department of Transportation. A road construction project near you could be in jeopardy.

The high price of gas is the real problem. It's got most of us trying to figure out where we can cut back. But every time you save a gallon, it costs the state 36 cents. Save a 20-gallon tankful, and that adds up to $7.20 less for highway construction and maintenance.

No one knows just how bad the problem is yet.

"But It's substantial," said David Dye with the state DOT. "It's probably not a billion-dollar problem, but it is a hundred million-dollar plus problem."

So who's worried? Try the governor.

"We can't go to the gas tax. That isn't going to work anymore. It isn't working now. We can't simply say to ferry users, 'we're going to up you every time we have a need for more money.' We've got to have a whole new way of doing business," said Gov. Chris Gregoire.

The governor says whether we ride the ferries or our cars, we are now all in the same boat.

This talk of gas tax woes began as state officials celebrated the one-year anniversary of the Tacoma Narrows bridge. They called it a huge success and applauded each other, then admitted the $735-million span would probably cost so much it couldn't be built today.

"Steel prices, because of the competition with China, gas prices rising exponentially," said Dye. "All of those things create a perfect storm not only on the revenue side, but on the construction cost side."

That means don't bet on everything moving as well as it does on the Narrows bridge.

Transportation planners still plan road improvements. But they warn the gas price crisis could slow both construction and maintenance programs.

The governor says one answer is a new federal highway construction and maintenance program. Without that, she says every state is in trouble. She also says tolls are in everyone's future.

Tolls may not be enough for the multi-billion dollar 520 bridge replacement. The DOT says that could mean some form of new local tax, perhaps higher license tab fees.