General Motors Corp. will announce new options to OnStar at the Chicago Autoshow on Wednesday, ten years after it first introduced the safety and navigation system.

OnStar Turn-by-Turn Navigation features voice-guided directions delivered through the radio speakers to guide the driver to their destination. Drivers call an operator and ask for audio directions, which is downloaded to the car by the operator.

"With some software changes in our module, and without a screen in the vehicle, the OnStar advisor can download the information to the system in your car," said OnStar president Chet Huber. "As you drive and approach the next turn, the radio will mute and the driving instructions come on to tell you to turn right or left"

Today, OnStar owners press a button to dial an operator to get audio directions based on their location, which is determined by satellite. The directions are read off by the operator. The system lets customers tape the directions and play them back as they drive, but there wasn't an onboard software application to let the operator download the information to the car.

The new system is safer because drivers never need to take their eyes off the road. No data entry or touch screen distracts drivers from the road.

The price for the service hasn't been set. That should come within the next two months, said Huber. The package is being launched in the Buick Lucerne and the Cadillac DTS, followed by the Cadillac STS in June.

About 4 million drivers now have OnStar. GM plans to make OnStar standard on all vehicles by 2007.