WARREN, Mich. -- The 2004 GMC Savana and Chevrolet Express, the industry's first and only 15-passenger vans with a stability enhancement and traction control system, will go on sale beginning in early November, General Motors announced.

"Equipping our 15-passenger vans with the StabiliTrak stability enhancement system makes what we believe is already a very safe vehicle even better by providing our customers with another important tool to help them avoid some of the conditions that can lead to a crash," said Robert C. Lange, GM executive director, structure and safety integration.

StabiliTrak with traction control is standard on all 2004 GMC Savana and Chevrolet Express 15-passenger vans produced after Oct. 6.

"We expect that the addition of this important safety system will further distinguish the Savana and Express from all other 15-passenger vans," said Ray Chess, vehicle line executive for the vans.

Stability enhancement systems help drivers maintain control of vehicles during certain difficult driving conditions such as ice, snow, gravel, wet pavement and uneven road surfaces. The systems also assist in maintaining control during emergency lane changes and avoidance maneuvers.

GM's system works by recognizing wheel skid. Sensors detect the difference between the steering wheel angle and the direction the driver is actually turning by "reading" the steering wheel position, the amount of sideways force in play, vehicle speed and the vehicle's response to steering wheel input.

The system then uses the brakes to enhance control of the vehicle's direction and to help keep it on course. The system automatically reduces the engine torque and applies precise amounts of pressure to front right or left brakes to help keep the vehicle on track. These brake and engine interventions help realign the vehicle's actual path with that being steered by the driver.

GM began installing stability enhancement systems in passenger cars in 1997. The company now has more than 2 million equipped vehicles on the road. GM has also installed stability enhancement systems in full-size sport utility vehicles.

Lange said that while stability enhancement systems help drivers avoid some of the conditions that cause crashes, no system is foolproof.

"We will keep educating our customers on the unique loading and operating characteristics of full-size, extended passenger vans," Lange said. "We support the advice of the National Highway Traffic Safety Administration that drivers and passengers in vans -- and all other vehicles -- always use safety belts. And we remind all vehicle occupants to obey state seat belt use and child passenger safety laws."

The Savana and Express 15-passenger vans have a 155-inch wheelbase, the longest in the 15-passenger van segment. The longer wheelbase and other chassis design features help improve handling characteristics that allow the driver more control under various road conditions.

Other standard crash-avoidance features include four-wheel antilock brakes for directional stability in emergency braking situations and daytime running lamps for improved visibility. Safety belts, driver and front passenger air bags, front and rear crush zones and side-door beams are standard features designed to help protect occupants in the event of a crash.

The vans are produced at GM's Wentzville, Mo., assembly plant.