Charges are pending against a driver who struck two Cook County Sheriff's squad cars on the Jane Addams Tollway and sent two officers to the hospital late Tuesday, authorities said Wednesday.

The officers were conducting a traffic stop on eastbound I-90 near Arlington Heights Road when the driver of a 2008 Acura TL sedan struck their cars at 11:07 p.m. Tuesday, according to the Cook County Sheriff's Office and Illinois State Police.

State Police Trooper David Roman said the driver of the Acura was traveling in the far left lane when, for unknown reasons, he veered off to the shoulder and struck the vehicles.

The Acura crashed into one squad car, which then rammed into the other squad car. One sheriff's deputy was outside his car; the other was inside, and had to be extricated, said Sam Randall, a sheriff's office spokesman.

Both officers were transported to area hospitals for injuries that were described as not life threatening. One of the officers was treated and released, and the other is expected to recover, Randall said.

The driver of the Acura also sustained nonlife threatening injuries, authorities said.

Illinois State Police continue to investigate the crash.

Daily Herald staff writer Lee Filas contributed to this report.