SHERIDAN — Investigators are still looking into a serious crash involving a New York State Police vehicle that took place in the westbound lane of Interstate 90.

The crash Monday took place between exits 58 and 59. Also involved, according to police, was a passenger vehicle with five occupants.

Both westbound lanes were closed due to the collision. Traffic was diverted at the Silver Creek exit to allow two helicopters to land.

The severity of injuries wasn’t known. A call to the Thruway police barracks wasn’t immediately returned.

Traffic was backed up several miles, police said.

“Motorists may wish to seek an alternative route,” police said in a statement. “More information will be released as it becomes available.”