Dear Dr. Gridlock:

I drive infrequently on the Capital Beltway, but when I do, it is typically around rush hour, and the high-occupancy toll lanes might be worth the money when I want to shorten the travel time from Interstate 66 into Maryland.

However, while heading along that route on my way to Baltimore-Washington International Marshall Airport last week, I realized that the Beltway HOT lanes end somewhere between the Dulles Toll Road and the American Legion Bridge.

I was wondering what happens when the HOT lanes need to merge back onto good old I-495. Without a continuation of the HOT lanes to at least Kensington, all that I see is a new bottleneck. What good are the HOT lanes if they only provide 14 miles of relief?

— T.J. Kozikowski, Fairfax

Some elected leaders from Montgomery and Fairfax counties were thinking along somewhat the same lines when they held an unusual meeting in July. It was unusual in that elected leaders from the D.C. region’s two largest jurisdictions aren’t in the habit of talking over one of the region’s biggest transportation concerns: How do you keep commuters moving when there’s a river in the way?

The answer, regionwide, is a resounding, “We don’t know.”

In the immediate future, there’s the HOT lanes project, scheduled to open by the end of this year, and then there’s a bunch of ideas about what we could do if there was money and political will.

The idea that seems the most doable is a commuter bus service that would link the I-270 corridor with Tysons Corner. When a previous incarnation of this service, called the SmartMover, got going a little over a decade ago, I thought it was a no-brainer, can’t-miss plan.

And then it missed. After a few years, the bus service was canceled. Only a handful of commuters had used it. The service wasn’t reliable enough or frequent enough. Buses tended to get caught in traffic, just like everyone else.

What if we gave the buses their own lanes on the Beltway and the bridge? You can’t add bus lanes to the bridge as it is now. Buses aren’t that skinny.

We could rebuild the bridge, if we could find a couple of billion dollars nobody wanted to use for anything else.

Meanwhile, Fairfax leaders are hoping to see a surge in bus commuting via the Beltway HOT lanes, getting better known now as the 495 Express Lanes. Buses, like carpoolers, can get a free ride in these four new lanes between Springfield and the Dulles Toll Road.

But these new lanes are strictly a Virginia deal, not a regional one, and the potential consequences of that are of concern to Kozikowski and many other travelers who cross the river.

Those who write to me tend to worry about two things: What will happen at the merge point, where the express lanes and the regular lanes come together, and what will happen farther north, when those drivers reach the Legion Bridge and the already heavy traffic north of the bridge?

Since I can’t tell them that things will get any better in those areas, let me offer reasons to hope they won’t get much worse, at least not in the near future.

The key factor is that the target customer for the express lanes is the Virginia commuter, someone going a few exits along the Beltway and looking to get a a more-reliable trip by using the toll lanes.

The key destination for those commuters is Tysons Corner. The Transurban company, which will manage the new lanes, doesn’t expect very many customers to continue north of that area.

Consider also that the express lanes are more likely to draw commuters to them from the regular lanes rather than to add new commuters to the Beltway. (Really, would you commute on any part of the Beltway if you didn’t have to?)

The crisis many drivers fear isn’t likely to come in 2013. But as they know so well, the traffic on the Maryland side of the Beltway is awful right now, and a little breathing room shouldn’t be added to the excuses for not dealing with it.

Dr. Gridlock also appears Thursday in Local Living. Comments and questions are welcome and may be used in a column, along with the writer’s name and home community. Write Dr. Gridlock at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or e-mail