UPDATED 3.15pm: Another semi-trailer has been claimed by the Mona Vale Road descent.

This morning, traffic on Mona Vale Road was heavily impacted with one lane closed and a contra-flow (stop-slow conditions) in place.

Motorists were warned to expect significant delays with traffic backed up to Samuel Street westbound and Chiltern Road eastbound.

At 6.50am, a loaded semi-trailer carrying a 40 foot container ran off the road and crashed over concrete road barriers, becoming stuck approximately one kilometre west of the Ponderosa Parade/Samuel Street roundabout, about 300m north of Laurel Road East.

Mona Vale Rd truck crash

The vehicle sustained significant damage and had not been moved at 10.00am, with traffic contra-flow management ongoing. Emergency services attended the scene. The truck driver was being treated for head injuries and shock.

A spokesperson from the Transport Management Centre said a salvage operation was underway. A crane was required to remove the vehicle and the fuel had to be drained, resulting in a significant delay before the truck was moved.

The spokesperson warned that Mona Vale Road would be closed in both directions shortly after 11.00am between Ponderosa Parade and Powderworks Road.

Mona Vale Rd truck crash

The road was re-opened in both directions shortly after 3.00pm.

While diversions were in place, eastbound light vehicles were diverted via Powderworks Road while westbound light vehicles were diverted via Ponderosa Parade. Heavy vehicles were diverted via Pittwater Road, Wakehurst Parkway, Warringah Road and Forest Way.

The Transport Management Centre has advised motorists to monitor livetraffic.com as this section of road is expected to close again later tonight as the salvage operation continues.

Bus routes 196 and 197 that were diverted away from Mona Vale Road in both directions during the closure are returning to their usual routes.

Images: Northern Beaches Advocate, RMS