Virginia Department of Transportation image shows travel time sign on  I-95 in Dumfries.

Morning commuters on northbound Interstate 95 now pass by a sign displaying the travel times to the Pentagon in the regular lanes versus the High Occupancy Vehicle lanes. Since the new sign almost always will 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 when 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 I-64 and the alternative route on I-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 Bridge or go west on the Beltway to the American Legion Bridge. One other place I think commuters would love to see such signs: along the west side of the Capital 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 expansion 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 so they can use the HOV lanes or take buses to save time.

The travel time information on the sign is updated every five minutes. The sign also displays the status of the gates controlling entry into the northbound HOV lanes.

When the morning HOV hours end and the lanes open to all drivers, the sign will continue to display the travel time for the HOV lanes, as long as they are open to northbound traffic.

When the HOV lanes are reversed to flow southbound, or when they are closed for construction of the express lanes, the sign will first display “CLOSING” and then “CLOSED.”

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 to the Pentagon, since 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.