Washington area residents: Are you resigned to sitting in endless traffic jams? Do you assume nothing can be done? Think gridlock here is as inevitable as death and taxes?

If so, you’re wrong.

A local traffic study and an opinion survey published by The Washington Post last week show that genuine, noticeable reductions in travel time are achievable if smart choices are made and sufficient money is spent.

Replacing the Wilson Bridge, expanding the Capital Beltway and building the Intercounty Connector are among the projects that have helped shrink congestion in measurable ways. The survey of those who drive to work found that their average commute time has dropped from 37 minutes in 2005 to 31 minutes today.

Moreover, that’s only a taste of what’s possible. An unusual confluence of events has created a rare opportunity today for our region to do even more to unclog roads and improve the quality of life.

Both Virginia and Maryland passed historic tax increases in the spring to raise additional billions of dollars for roads and transit. The new money is arriving just as two important, long-term trends improve the odds that the money could actually lead to appreciably less time wasted in backups.

First, people are driving less, both in the Washington region and the rest of the nation. It’s partly because of the 2008 recession. But other contributors are telecommuting, online shopping and a mind-set among the younger generation, which is less attached to the automobile than any other since World War II.

“Clearly something has changed. We currently are witnessing the largest sustained drop in driving we’ve ever seen,” said Robert Puentes, a senior fellow at the Brookings Institution’s Metropolitan Policy Program. “A lot of this is being driven by younger folks driving much less.”

Second, our area is seeing the benefits of so-called smart growth policies designed to concentrate development around mass transit, especially Metro stations, and generally encourage alternatives to driving.

Those two trends are crucial, because they help to break the self-defeating cycle known as “induced traffic.” That’s what happens when a road built or expanded to reduce congestion instead stimulates development that causes traffic to remain just as bad or become even worse.

Today, with people driving less and development planned more intelligently, we have a shot at expanding road capacity without contributing to the problem.

What’s the catch?

First, and most obvious, we have to spend the money on the right mix of investments in road and bridge projects, Metrorail, bus service, and bike and pedestrian facilities. The public needs to insist that its tax dollars pay for a balanced approach that will yield the greatest overall reduction in congestion.

“We are in a remarkable moment in terms of the dollars available. I think this is a watershed conversation,” said Arlington County Board member Mary H. Hynes (D), who sits on both the Northern Virginia Transportation Commission and the Metro board. “We really have to get clear with people what we’re going to do.”

Second, the region, as a whole, needs to settle some persistent, major battles over what to build. It should prevent drawn-out struggles that sap time and energy.

Four disputes that cry out for resolution are:

What to do about I-66 and I-395 inside the Beltway? Those stretches are among the worst bottlenecks in the region, but Arlington has consistently blocked efforts to widen them.

The Bi-County Parkway linking Loudoun and Prince William counties: Yea or nay?

Will Maryland widen I-495, especially from the American Legion Bridge to College Park? This is another of the worst stretches in the region, yet it doesn’t seem to be much of a priority for state and county officials. (Virginia and Maryland should expand that bridge, too.)

Finally: Will the region ante up the big bucks needed for Metro’s long-term expansion plans, including adding eight-car trains and, ultimately, a second Potomac tunnel?

There’s money on the way and reason to believe that it can make a sizable dent in what’s often called the region’s biggest problem. Let’s not blow this chance.

I discuss local issues Friday at 8:50 a.m. on WAMU (88.5 FM). For previous columns, go to washingtonpost.com/mccartney.