CHICAGO (AP) – Illinois State Police are seeing a spike in crashes involving parked squad cars and passing vehicles, despite a law that was enacted nearly 20 years ago to make roads safer for emergency responders.

The Chicago Tribune reports that state police have seen at least a dozen such crashes so far this year, which is more than last year’s total.

Police say most of the crashes occurred when it was dark. Injuries were reported in nine cases, while a January crash resulted in the death of a trooper.

Sgt. Delila Garcia says it’s unclear what’s behind the spike. She says driving too fast or driving under the influence could be factors.

State law requires motorists to slow down and move over when there’s a stopped vehicle with flashing or hazard lights.

Information from: Chicago Tribune, http://www.chicagotribune.com