A one-vehicle accident on Route 15 in Milford is causing delays on the parkway Friday morning.

The accident, reported around 8:10 a.m., has closed the left lane between exits 56 and 55.

The state Department of Transportation said traffic speeds in the area are averaging 11 mph.

Around 8:25 a.m., DOT said it’s taking 27 minutes to travel soundbound five miles from Route 34 to the Milford connector.