The completed work will mean that a trip up the parkway will be possible from Braddock Road to Virginia Route 7. Other changes in the area include additional traffic lights and an extension of Shreveport Drive.

WASHINGTON — It is only about a mile long, but a missing link in Loudoun County’s road network that opens Wednesday could transform commutes and traffic patterns.

The last segment of the Loudoun County Parkway, just north of U.S. Route 50, and a new intersection with Old Ox Road mean a complete 13-mile-or-so trip up the Loudoun County Parkway will now be possible from Braddock Road and South Riding, across Route 50 past Arcola and Brambleton, up by Ashburn and Sterling to Virginia Route 7.

“The big connection will be Loudoun County Parkway, all the way from Route 50 to Route 7,” said Jennifer McCord of the Virginia Department of Transportation.

The final segment of the parkway was built as part of a proffer agreement by a developer, while VDOT is responsible for the new intersection with Old Ox Road. Widening work on Old Ox will continue over the next year to expand it from one to two lanes in each direction in that area just west of Dulles International Airport.

The $119 million Old Ox Road interchange and widening project is funded by the state, Loudoun County, the Northern Virginia Transportation Authority and Metropolitan Washington Airports Authority.

Other changes in the area include additional traffic lights and an extension of Shreveport Drive.

Combined, the connections could offer an alternative for some drivers to Virginia Route 28, but it could also add additional traffic to existing sections of the Loudoun County Parkway.

Dulles District Supervisor Matt Letourneau, who represents part of the area impacted by the changes, celebrated the construction milestone in a message to constituents as a fix for what had been one of the highest-priority of a number of long-term missing roadway links across Loudoun.

Last week, traffic shifted in the area to allow workers to finish painting lane markings and to update road signs.

Wednesday morning, some of the new turn lanes are scheduled to open and the new traffic light is scheduled to turn on.

After a ribbon cutting Wednesday afternoon, the full intersection is scheduled to open by Thursday morning’s rush hour, weather permitting.