Take the No Love for Litter Pledge


About the Project

Route 123 Interchange

Major reconstruction is planned for the Route 123 (Chain Bridge Road) Interchange as part of the Transform 66 Outside the Beltway Project. The new interchange design:

  • Provides access to and from the future Express Lanes from I-66 East and West
  • Improves safety at the interchange
  • Connects the City of Fairfax and the planned George Snyder Trail with the new shared-use path and neighborhoods in Oakton with a grade-separated trail through the Route 123 Interchange

Get a closer look at what’s planned through the Transform 66 Interactive Map.

Route 123 (Chain Bridge Road) Traffic Shifted to New Bridge Over I-66

Route 123 (Chain Bridge Road) northbound and southbound traffic has shifted to the new Route 123 North Bridge over I-66. The old Route 123 North and South bridges are being demolished to allow for construction of a new Route 123 South Bridge, shared-use path, and new ramps to I-66 general purpose and Express Lanes.

Access to and from I-66 at Route 123 will remain in its current configuration during this phase of construction.

As construction continues through 2022 on the Route 123/I-66 Interchange, drivers should be alert for changing traffic patterns. Drivers are reminded to slow down and pay attention to lane markings and roadway signs at all times. 

The travel lanes of southbound Route 123 over I-66 shifted on to the new Route 123 Bridge on Jan. 21. Access to/from I-66 East and West will remain the same. 

Construction Update (Updated September 7, 2021)

Recent Construction Progress:

  • All I-66 East lanes have been shifted to new pavement on the right side (outer portion) of the roadway between Jermantown Road and Blake Lane as construction activities begin to focus on building the future I-66 Express Lanes in the center of the roadway  
  • Route 123 traffic over I-66 has shifted to the new Route 123 North Bridge (Northbound shifted on Dec. 30, 2020; Southbound shifted on Jan. 21, 2021)
  • Demolition of the old Route 123 bridges over I-66 is complete 
  • Beams have been installed for the new Route 123 South bridge

Upcoming Construction Activities:

  • Construction of deck and approaches for the new Route 123 South Bridge
  • Overnight demolition of the remaining bridge piers along I-66
  • Shift Route 123 South traffic to new bridge
  • Open Express Lanes and new ramps

Bridge deck is being constructed for the new Route 123 South bridge. (July 12, 2021)

Looking west toward the I-66 East travel lanes, which have been shifted to new pavement on the outside of the roadway to allow construction of new express lanes ramps. (July 12, 2021)

Looking east from the Route 123 bridge toward a new storm water pond and the I-66 East travel lanes, which have been shifted to new pavement on the outside of the roadway. (July 12, 2021)

I-66 West has been shifted to new roadway (dark pavement) in the Route 123 area as construction advances on new ramps in the center portion of the corridor. I-66 East will shift to the outside in fall 2021. Concrete deck is in place for the new Route 123 South Bridge over I-66. (August 24, 2021)

What Neighbors Can Expect

  • Noisy construction activities such as bridge demolition and pile driving will be avoided at night, when possible. Noise to expect at night includes back-up alarms on equipment and trucks, which is necessary to protect worker safety.
  • Lighting of the construction work area will be directed to minimize light pollution for nearby residents.
  • Project emails and website will be used to communicate major traffic switches or nighttime work.


Anticipated Schedule Dates
Clearing activities begin Spring 2018
Traffic pattern shifts begin April 2019
Ramp and bridge work begin Summer 2019
Demolition of ramp from I-66 West to Route 123 South January-February 2020
Traffic shifts to new Route 123 bridge span
December 30, 2020
Demolition of old Route 123 bridge span January-February 2021
Construction of second Route 123 bridge span begins Winter 2021
Express Lanes open December 2022


Concept plans (I-66) - PDF, 13.7MB
Concept plans (Rt. 123) - PDF, 12.6MB
Cross sections - PDF, 16.9MB
Plan and profile - PDF, 36.4MB
Planned I-66 trails near Route 123 - PDF, 1.5MB
Upcoming traffic changes (April 2019) - PDF, 424KB
Upcoming traffic changes (July 2019) - PDF, 396KB
Construction Update Meeting on September 4, 2019 Flyer - PDF, 1.3MB
Route 123 (Chain Bridge Road) South Flyover Ramp Demolition - Jan, 2020, - PDF, 5.6MB
Traffic Pattern Changes for I-66 East to Route 123 North on Feb. 21 - Website
Traffic Changes at Route 123/I-66 Interchange Starting on or about March 21 - Website
Flyer on Rose Forest Drive Closure and Detour (Sept. 2020) - PDF, 1.7MB
Route 123 Bridge Demolition Flyer (12/21/20) - PDF, 2MB