WASHINGTON (Map, News) - The daily bumper-to-bumper slog of the Montgomery County commute is only going to get worse between now and 2012 as long-planned road improvements are overrun by traffic from the rapidly growing neighborhoods on the county’s north side, a county traffic report says.

County officials said that by 2012 they expect to have finished the Intercounty Connector between Georgia Avenue and U.S. Route 1, pulling some traffic off crowded city streets. And plans for expanding the National Naval Medical Center in Bethesda as part of the Base Realignment and Closure process will include improvements to already-failing intersections where Jones Bridge Road and East West Highway meet Connecticut Avenue.

But Montgomery County motorists can expect to spend 16.1 percent more of their time, roughly 50 hours, stuck in traffic in 2012 than they did in 2005. That’s because at least 38,000 new homes and 127,000 new jobs are expected in the next four years. Two-thirds of the growth will be in the northern half of the Interstate 270 corridor, the report said.

And already residing in that area are some of the county’s worst intersections, which won’t likely improve as approved projects get under way, said Ronald Vaughn, a county transportation planner.

Developers who start planning projects after July 1, however, will have to meet new standards in Montgomery Village and North Potomac.

They will have to include in their projects plans for encouraging public transportation, widening roads and otherwise balancing the increased traffic.

But not everyone is convinced those requirements will improve the situation.

Terry O’Grady, a Montgomery Village resident and a founder of the Mid-County Citizens Alliance, said the county’s plans to build several thousand homes clustered around the Shady Grove Metro station and move county facilities from there to Middle Village and other areas in the northern portion of I-270, “will make traffic much worse throughout the area. Smart growth is one thing, but density of that type — whether near a Metro station or not — is problematic.”

fklopott@dcexaminer.com