The 17-year-old driver of a stolen car and a Howard County police officer were injured early today when both the youth's car and the officer's cruiser jumped a guardrail on Interstate 95 during a chase.

The incident began at 4:30 a.m., when an officer saw a Honda Accord leave a Laurel apartment complex at the same time an alarm sounded.

Detective Michael Sherman said the officer followed the car onto northbound I-95 for five miles while he checked the vehicle's license tags.

When the officer learned the tags were stolen, he called for help. Two other police cruisers attempted to "box" the car in, Sherman said.

All three cruisers had their emergency lights on, Sherman said, when the youth sped up, then swerved left into a police car.

Sherman said both cars jumped a guardrail. The police car toppled over several times before it came to a stop near Montgomery Road.

Officer Robert Castor, a five-year police veteran, was treated at St. Agnes Hospital for minor injuries and released. The youth, whose name was not released, is a resident of Virginia. He was taken to the Shock-Trauma Unit in Baltimore, where he was admitted.

The car was later found to have been stolen, Sherman said. Criminal and motor vehicle charges against the youth are pending.