Brake lights are a familiar sight on southbound Interstate 95 at the merge from four lanes to three lanes at the Fairfax County Parkway.

But that may dissipate this Friday when a fourth lane of southbound I-95 opens at that location.

Just in time for Friday night’s evening commute, the Virginia Department of Transportation will open the new lane, which spans a five-mile distance from the Fairfax County Parkway south to the U.S. 1 exit, just north of the Occoquan River Bridge.

VDOT estimates travelers will shave 10 minutes off their travel time, possibly more.

 ”Drivers on I-95 South will feel the benefit of this additional lane immediately,” said VDOT project manager H.S. “Charlie” Warraich in a written statement Wednesday. “It is the best traffic improvement in this corridor since the completion of the Springfield Interchange.”

VDOT opened a fourth northbound lane on I-95 in the same area last December. The last piece of the project will add a fourth lane to the Occoquan River Bridge in both directions. That work will be done by summer 2011, according to VDOT.

Virginia MegaProjects has published a brochure on the project, which includes a map.