Washington area drivers must squeeze through four of the country's 20 worst highway bottlenecks, all of them along the Capital Beltway, according to a study released yesterday of traffic choke points on non-toll freeways.

The analysis by the American Highway Users Alliance, which lobbies for road construction, ranked the interchange of the Beltway and Interstate 270 as the worst bottleneck in the region and the fifth-worst in the country, as measured by the hours drivers waste trying to traverse the junction. Motorists lose an average of 79 hours a year passing through there, the study found.

Other choke points on the national list are the Springfield interchange, ranked sixth; Interstate 66 at the Beltway, 16th; and Interstate 95 at the Beltway in Maryland, 17th.

"Failing to improve the roads and deal with growth has been a mistake, and we're paying for the mistake," said William D. Fay, president of the alliance, which includes AAA, highway contractors and the trucking, oil and automobile industries. "There's hope. We need to make these investments."

Topping the list is the junction of Interstate 405 and Interstate 10 in Los Angeles, home to five of the country's most severe bottlenecks. The only other metropolitan areas that had more than one bottleneck in the top 20 were Atlanta and Houston.

The bottlenecks were ranked according to total time wasted, which was based on the number of vehicles passing through each location, and not by the time it would take an individual driver to get through. Nor did the study examine toll roads and bridges, which explains why none of the 20 choke points are in New York, widely considered to have some of the worst traffic tie-ups in the country.

In total, researchers evaluated 167 locations in the country's 30 most congested metropolitan areas, studying 1997 information provided by regional planning agencies and state transportation departments.

The finding that nearly half of the worst bottlenecks are in Los Angeles and Washington reinforces the conclusion of another national study that those two metropolitan areas have the worst and second-worst congestion in the country. In that study, released last week, the Texas Transportation Institute reported that Washington, for the fifth consecutive year, has the second-most severe traffic, forcing drivers to waste 76 hours a year in tie-ups.

The Highway Users Alliance rankings are included in a broader report that urges major new spending on road expansion. Such investment, the alliance projected, would significantly reduce commute times, crashes and air pollution.

But a study two months ago by the Surface Transportation Policy Project, a Washington-based advocacy group that favors expanding transit over roads, found that drivers often lose more time during highway construction than they recoup once the project is finished.

"There's plenty of evidence that just building highways doesn't improve bottlenecks and could make them worse," said Don Chen, of the policy project. "The lesson is not that we've let road construction go for so long but that we've let integrated transportation solutions, including transit, go for so long."

The four Washington area bottlenecks in the alliance's top 20 list all have drawn the attention of transportation officials. Earlier this year, Virginia began a $400 million project to rebuild the Springfield "Mixing Bowl," and it is conducting a study into widening the Beltway in the state and rebuilding all the interchanges. Maryland is conducting its own study of possible expansions and improvements along its portion of the Beltway.

CAPTION: Bad Bottlenecks (This graphic was not available)