As repairs to New Jersey’s oldest bridge and the construction of a new bridge next to it move forward, a portion of Route 206 will be closed completely from July through October, the New Jersey Department of Transportation (DOT) announced at a public information meeting yesterday.

Route 206 south of Princeton will be detoured for all vehicles from July to October, and there may also be overnight closures before July that will reduce 206 to one lane with alternating traffic. There has been a signed truck detour in place for vehicles weighing more than 20 tons since emergency repairs were made more than a year ago, and that detour will remain in place throughout construction, which is scheduled to be completed by December.

The roadway was first closed on February 22, 2016, due to a failure of the parapet and spandrel wall above the north arch on the upstream side of the stone arch bridge. An in-depth inspection of the bridge revealed additional problems. The DOT performed emergency repairs, and the road was reopened to traffic on March 7, 2016.

Extensive leaning and bulging of the spandrel walls and parapets required a more thorough rehabilitation to retrofit the structure for strength, safety, and durability. Temporary concrete barriers installed during the emergency repairs will be removed as the repairs are completed.

In addition to the rehabilitation of the stone arch bridge, which was originally constructed in 1792 and widened in 1916, the project will include the replacement of the flood channel bridge, directly adjacent to the stone arch bridge. Constructing the two bridges at the same time will minimize the duration of the construction and detours. The flood channel bridge concrete deck is in poor condition with significant deterioration in both superstructure and substructure.

It will be replaced with a single span bridge, whose north abutment will be moved south to avoid demolition and excavation in the vicinity of the Worth Mill ruins, which are to be protected during construction. A single span structure will minimize environmental impacts and obstructions in the waterway.

The project is located within the historic districts of the Princeton Battlefield/Stony Brook Settlement Village and the Kings Highway Districts. Archaeologic monitoring and documentation will accompany the construction.

Truck detour over 20 tons (regional) — in place now:

Northbound — From Route 206 north take I-95 south to Route 31 north to Route 202 north back to Route 206 at the Somerville Circle.

Southbound — From Route 206 south take Route 202 south at the Somerville Circle to Route 31 south to I-95 north back to Route 206.

Truck detour over 4 tons — from July through October:

Northbound — From Route 206 north turn left on Carter Road, then right on County Route 518 back to Route 206.

Southbound — From Route 206 south turn right on County Route 518, then left at Route 31 south to I-95 north back to Route 206.

Car detour — from July through October:

Northbound — From Route 206 north take a left on Carter Road, right on Rosedale Road, then a right on Elm Road back to Route 206.

Southbound — From Route 206 south take a left on Lovers Lane, right on Mercer Road, then a right on Hutchinson Street back to Route 206.