Traffic flows over the American Legion Bridge along I-495, the Capitol Beltway. (Chip Somodevilla/Getty Images)

When elected leaders from Montgomery and Fairfax counties met in July for what many said was their first joint discussion of regional transportation concerns, it was only natural that the conversation focused on the American Legion Bridge. Each day, the counties use it to exchange tens of thousands of commuters.

But the Legion Bridge tends to be less talked about and fussed over than its cousin, the Woodrow Wilson Bridge, on the other side of the Capital Beltway.

The Wilson Bridge, part of Interstate 95, the East Coast’s Main Street, is just emerging from a major makeover that widened not only the bridge but also its approaches. The last big thing that happened to the Legion Bridge was in 2007, when it got a paint job — underneath, where nobody could see it.

Now, with Virginia widening the west side of the Beltway for the high-occupancy toll lanes, the bridge just north of the new lanes may be in for a new round of attention. So let’s look at its history, its role in regional traffic and some visions for its future.

A half-century

The span is approaching its 50th anniversary. It opened Dec. 31, 1962, completed at a cost of $2.8 million. “I’m nostalgic already,” Montgomery County Council President Roger Berliner (D-Potomac-Bethesda) said during the county leaders’ meeting when he heard that price tag.

In the early years, it was called the Cabin John Bridge. The name was officially changed to American Legion Memorial Bridge in 1969.

Opened with six lanes, the bridge now has eight through lanes, matching the configuration of the Beltway on either side of the Potomac, though the highway narrows farther north. Traffic is more than four times heavier than in the early years. In 1965, the bridge was used by 47,990 vehicles a day. By 2010, that number had grown to 232,000.

Capital traffic

At the meeting between the Fairfax and Montgomery officials, Ronald F. Kirby, director of transportation planning for the Metropolitan Washington Council of Governments, described several studies that have examined bridge traffic over the past decade. The studies show the complexity of driving patterns and suggest that solutions also may be complex:

●Among the Virginia drivers entering Maryland, 7 percent were heading for the Clara Barton Parkway and River Road, commuter paths into the District; 27 percent were bound for Interstate 270, Montgomery’s tech corridor; and 63 percent continued east on the Beltway.

●Among Maryland drivers, 11 percent were bound for Interstate 66; 23 percent for the Dulles highway; 3 percent for Route 7; and 24 percent for other destinations on the west side of the Beltway; 35 percent continued east on the Beltway.

●About three of every four trips are made by commuters. About eight of 10 motorists are driving alone. Carpoolers and vanpoolers don’t make up a big percentage of travelers. There’s no Metrobus service across the Legion Bridge.

●The most congested hour on the bridge is 8 to 9 a.m. A majority of the drivers are bound for Virginia. The direction of travel begins to reverse in the 2 p.m. hour.

●Traffic surveys for 2008 and 2011 discovered something very unusual for a D.C. area highway: Traffic got slightly better on the outer loop across the bridge between River Road in Montgomery and Georgetown Pike in Fairfax. What happened? In 2005, the exit to the Dulles Toll Road was widened and congestion reduced, showing that a relatively small fix can have a significant impact.

●Congestion on the inner loop during the afternoon rush just keeps getting worse. In 2011, the leading edge of the congestion was at the I-270 spur in Montgomery and stretched south along the Beltway to Route 267 in Fairfax.

What’s ahead

By 2040, traffic on the bridge could be 19 percent above its 2007 volume, according to a study cited by Kirby. With the bridge’s capacity limited, the extra traffic will mean even longer rush hours. Speeds in the peak direction could be 10 mph or less.

Since the Beltway fully opened in 1964, Maryland and Virginia have been adding capacity by adding more lanes. Virginia’s 495 Express Lanes project will add four lanes but with a twist: Drivers in the new lanes will use their E-ZPasses to pay a toll that rises and falls with the level of congestion, unless there are at least three people in the car, which qualifies them for a free ride if they have an E-ZPass Flex trans­ponder.

Lane management looks like the way of the future, but lanes can be managed in different ways.

Long-term options outlined in a Maryland State Highway Administration study include widening the bridge to make it part of a managed-lane system that could stretch west up I-270 and link up with the Virginia express lanes to the south, but there’s no financing in place for any such construction. The Maryland study, completed in 2009, estimated that widening the Beltway and the bridge would cost at least $800 million.

Would the managed lanes, if built on the Maryland side, be consistent with the Virginia style? For now, the two states are going with different systems. Maryland’s express toll lanes program does not provide free passage for those who meet the carpool rules, as Virginia’s high-occupancy toll lanes will.

In a shorter time frame, Maryland could attack specific points of congestion along the west side of the Beltway. Options include extending acceleration and deceleration lanes at interchanges or altering lane configurations.

Meanwhile, commuter bus service across the bridge is under discussion. The problem with commuter buses in the regular lanes is that they get stuck along with everyone else. “ ‘Why take this? I could be listening to my own music’ in a car,” Fairfax County Board of Supervisors Chairman Sharon S. Bulova (D) imagined a rider thinking.

The buses also would have problems sticking to schedules, so a better plan would include bus service in a managed lane system.

All options but the short-term traffic improvements will require cooperation and coordination across the river. The July meeting among the county leaders boosted hopes for that, but it was just the start of the bridge-building between local governments.