Some car thieves may be surprised when the vehicle they are trying to steal slows down when the police are chasing them.

OnStar announced a new stolen vehicle service, which will allow security advisors to slow stolen vehicles by sending a remote signal that reduces the flow of fuel to the engine. The company said Tuesday that its advisors can will soon be able to work with law enforcement authorities and send a signal to stolen vehicles so they slow down gradually.

The service will debut on some 2009 GM models. About 1.6 million cars, about two-thirds of them Chevrolets, will come equipped with the service.

A driver must report the theft, then call OnStar to request Stolen Vehicle Location Assistance, which relies on GPS for precise tracking. Once police have caught up with the vehicle, they can ask OnStar advisors to slow it down remotely. OnStar says that it has safeguards to ensure that advisors target the correct vehicle. A remote signal interacts with the powertrain system to decrease the fuel flow.

OnStar said the system will help reduce fatalities and injuries due to police chases.

"Stolen vehicle slowdown will prevent the very real danger to the public and emergency responders of high speed pursuits," Richard Taylor, ComCare Emergency Response Alliance Chairman, said in a statement.

OnStar is a member of ComCare, a non-profit national advocacy organization representing more than 100 member groups focused on improving emergency response.

Vehicles must have electrical systems, wireless service, and GPS satellite signals in order for OnStar to work, and owners must subscribe to the services. Beginning January 1, OnStar will only offer services through equipment that runs on digital networks.