A cyclist was seriously injured on a busy St. John's highway Friday, when he slammed into a truck that had been pulled over to the side of the road.

The man struck a commercial truck that had stopped on a shoulder along the Outer Ring Road around 12:45 p.m., near the Portugal Cove Road interchange.

He was rushed shortly afterwards to the Health Sciences Centre and was listed in critical condition, the Royal Newfoundland Constabulary said.

Westbound traffic was temporarily reduced to one lane along a stretch of the Outer Ring Road.

The RNC said it is investigating the accident.