Morning commuters on northbound Interstate 95 now pass a sign displaying the travel times to the Pentagon in the regular lanes vs. the high-occupancy vehicle lanes. Because the new sign will almost always show a time savings for those who choose the carpool lanes, the Virginia Department of Transportation hopes it will inspire solo commuters to pick up at least two passengers for the trip north.

VDOT is trying to limit congestion on I-95 during the height of the construction program for the 95 Express Lanes, high-occupancy toll lanes that will replace the HOV lanes in the I-95 median in 2015 after construction is done.

It’s not the first use in Virginia of a travel-time comparison. VDOT has a similar sign in the Hampton Roads area showing beach-bound drivers their travel time on Interstate 64 and the alternative route, on Interstate 664 through Chesapeake.

In Maryland, southbound drivers on I-95 see an overhead message board that sometimes displays the travel time to Virginia if they take the Capital Beltway to the Woodrow Wilson Memorial Bridge or go west on the Beltway to the American Legion Memorial Bridge.

One other place I think commuters would love to see such signs: along the west side of the Beltway, in Virginia, near the points where drivers can choose whether to take the express lanes or the regular lanes. Since the 495 Express Lanes opened in November, drivers have been trying to figure out whether it’s worthwhile to pay the toll for the reliable trip or take their chances in the regular lanes.

Signs announcing Beltway travel-time savings to Tysons might also encourage commuters to switch from cars to the rush-hour buses that use the express lanes.

VDOT has expansion plans for this type of travel-time sign but doesn’t have the funding for it right now, said Michelle Holland, a VDOT spokeswoman. Meanwhile, she said, VDOT will evaluate the effectiveness of the new sign as drivers become accustomed to it.

The I-95 sign is at milepost 153, near the Dumfries exit to Route 234, 28 miles south of the Pentagon. The drivers who see it there have time to decide whether to pick up carpoolers at park-and-ride lots or board commuter buses for the same time-saving trip in the HOV lanes.

I hope that after the 95 Express Lanes open, the sign will continue to display the comparative information, but that’s not certain yet. If comparative travel times are displayed, they probably would be to the Beltway rather than the Pentagon, because the express lanes portion will end just north of the Beltway.

An alternative use of the sign would be to display the time for a trip in the regular lanes to the Beltway and to the Pentagon.

Expressing it

Last week, I encountered my first traffic jam in the 495 Express Lanes.

I’ve had enough experience with the lanes to know that I’m almost always better off using them when I need to reach a certain place at a certain time. On Thursday evening, I needed to get from Tysons around the Beltway to Silver Spring for my wedding anniversary dinner — clearly a case in which a commuter needs a reliable trip.

It was not to be. Because I was leaving the Gannett building, on the north side of Tysons, I went for the express-lanes entrance on Jones Branch Drive, a great time saver because it eliminates the need to reach a Beltway entrance farther away on Route 123.

As I swung left on the express-lanes entrance ramp, I got a shock: Ahead of me was a frozen sea of vehicles, stretching across the toll lanes as well as the regular lanes of the inner loop.

Farther south on the Beltway, drivers in the express lanes would sail past such congestion in the regular lanes, but my fellow sufferers and I were from only the merge where the toll lanes rejoin the regular lanes. Because of the congestion in the regular lanes, the merge point became the cork in the bottle, and the express lanes’ traffic was stymied.

If I had checked the toll rate on the message board before entering the express lanes, I would have had a clue about the traffic ahead.

The toll rate varies with the level of congestion in the express lanes. As many drivers have pointed out, a toll rate way higher than usual suggests that many people have moved to the express lanes. The theory is that you should join them, because the regular lanes must be really jammed.

At 6:20 p.m., the toll rate for the northbound segment out of Tysons could be as low as 35 cents. On Thursday evening, it was $1.70. According to the drivers’ theory, the high rate should have alerted me that the regular lanes were crowded. But the theory would not have helped me recognize that the express lanes also were at a standstill.

Now, wouldn’t a travel-time sign have removed any doubt?