Two lanes on I-78 westbound to close for weekend bridge work in Somerset County

SOMERSET COUNTY, N.J. — The two left lanes of Interstate 78 westbound are scheduled to be closed this weekend in Somerset County as part of the ongoing deck replacement project on the I-78 bridges over Washington Valley Road and Routes 202/206, according to the New Jersey Department of Transportation (NJDOT).

The closure will begin at 9 p.m. Friday, July 18, and continue through 5 a.m. Monday, July 21. It will affect westbound traffic from milepost 34.2 — just past the on-ramp from Martinsville Road/Exit 33 — through milepost 32.0, just before the bridge over Routes 202/206.

The lane closures are necessary to allow for deck panel repairs, milling and paving, and other structural work on the temporary bridge in the median over Washington Valley Road. All westbound traffic will be shifted into a single right lane “cattle chute” confined by concrete barriers. Exit 29 to I-287 will remain open during this time.

Motorists should expect delays and are urged to use caution through the work zone.

Oversized Truck Detour

An oversized truck detour that went into effect on May 2 remains in place and will continue until early 2026. The restrictions apply to all vehicles 8.5 feet wide or more and/or those weighing more than 40 tons.

Truck detour instructions include:

• From the NJ Turnpike: Take I-78 westbound Exit 48 to Route 24 westbound, then I-287 southbound to Exit 21B, returning to I-78 westbound.
• Local Access Between Exits 45 and 33: Vehicles must take I-78 eastbound to Exit 48 for Route 24 westbound, then follow to I-287 southbound and re-enter I-78 westbound at Exit 21B.

Oversized vehicles entering I-78 westbound between Exit 45 (Glenside Avenue) and Exit 36 (King George Road) will be redirected to Exit 33 for a U-turn to access the eastbound lanes and follow the detour route.

Project Details

The $67 million federally funded project involves replacing deteriorated bridge decks carrying I-78 over both Routes 202/206 and Washington Valley Road. Work also includes resurfacing roadways, updating guiderails, and constructing new approach slabs. Construction, which is phased to reduce impact on motorists, is expected to be completed by late spring 2026.

For real-time traffic information and updates, visit 511nj.org.