By: Chris Perkins, Senior Writer and Editor, GM News
How computers have kept GM vehicles stable in slippery conditions for more than 50 years
2026-07-31
By: Chris Perkins, Senior Writer and Editor, GM News
You may have never thought about traction control, but for years, it’s helped keep your vehicle on the straight and narrow. In essence, a traction control system maintains vehicle control by reacting when the tires spin faster than the vehicle’s speed of travel. In slippery conditions, the system can help the driver maintain control.
Traction control is standard in every mainstream new car for sale today, and 55 years ago, GM helped pioneer the technology.
The 1971 Buick Riviera is best known for its bold boat-tail styling, but the coupe also debuted a revolutionary piece of technology: Max Trac, the world’s first computerized system to detect and help prevent wheelspin. Max Trac was elegantly simple in execution, but remarkably forward thinking.
Image caption: 1971 Buick Riviera
The Riviera was a rear-wheel drive vehicle. Using speed sensors, one on the front wheels and one at the transmission, the Max Trac computer could detect any difference between the two. If the rear tires were spinning faster relative to the front wheels, the Max Trac computer would send a signal to the engine to reduce power, helping to bring the rear wheels back under control.
Max Trac was available as an option on the 1971 Riviera and expanded to the entire Buick full-size car lineup in 1972. Max Trac debuted six years before the first home computers hit the market. For many Buick owners, Max Trac might have been the first computer they ever bought.
In the half-century since Max Trac debuted, the creation of more capable computers and sensors has allowed GM engineers to refine traction control to a degree once thought impossible.
Image caption: Illustration from the 1971 Buick owner’s manual detailing the Max Trac system.
Anti-lock braking systems (ABS) use speed sensors at each wheel, giving a highly accurate picture of what’s happening at all four tires. Electronic engine management systems allow more precise control over the power being sent to the wheels. These modern developments give GM engineers highly advanced ways to improve traction control, detecting and responding to wheel slip faster and more accurately.
“It’s about giving you optimized wheelspin to keep the vehicle stable while preserving momentum,” says Arthur Drennen, GM Vehicle Performance Owner for Stability and Chassis Controls. “It lets you drive through what you need to drive through.”
Snow is a good example. On Max Trac-equipped Buick models of the early 1970s, the owner’s manual suggested turning off Max Trac when stuck in deep snow, as the system would reduce power and wheelspin that could help a driver get un-stuck. In modern GM vehicles, drivers rarely find themselves needing to turn traction control off to deal with situations like this. “It’s much better at keeping torque in the system,” Drennen says.
The advent of traction control enabled the creation of another system: Stability control, which helps prevent a vehicle from skidding or losing control while driving around a slippery curve. Since 2012, the U.S. government has mandated that all vehicles sold in America come equipped with stability control. In GM vehicles, traction and stability control are integrated into one system called Stabilitrak.
“With stability control, you have a steering-wheel angle sensor and an inertial measurement unit (IMU),” Drennen explains. “So, from the steering-wheel input, we know the path the driver wants to take, and from the accelerometer in the IMU, we know where the vehicle is actually headed.”
If the system detects a difference between where the driver wants to go and where the vehicle is headed, Stabilitrak can adjust the brakes, propulsion system torque, and all-wheel drive system (if equipped) to help the driver regain control. “The traction control system has grown from purely a power-reducing system to more of a torque distribution system,” Drennen says.
With the advent of user-selectable drive modes, drivers can tailor the traction and stability control system’s performance to a specific use case. Many high-performance vehicles offer a “track mode,” and off-road-focused vehicles include settings for sand or mud. On many family vehicles, Snow/Ice mode tailors the vehicle’s traction and stability control systems to help with confidence in slippery conditions.
EVs take traction and stability control to the next level. In an internal-combustion vehicle, Stabilitrak evaluates road conditions hundreds of times per second; in an EV, Stabilitrak can effectively infer road condition thousands of times per second.
That’s a wonderful capability unlocked by electric motors, which use sensors to precisely capture the exact position of the rotor that powers the wheels.
“We can look at the how fast the motor is accelerating, and in the case of wheelspin, determine that the motor is spinning up too fast to represent real tire grip,” Drennen explains. “Then we can reduce motor torque almost instantaneously.”
In a vehicle with an internal-combustion engine, the system first has to detect wheelspin before traction control can do its job by reducing engine power; in an EV, traction control starts working before undesirable wheelspin ever occurs.
All-wheel drive EVs, which have independent motors powering the front and rear wheels, offer even more control, allowing for precise torque output at both ends of the car. There’s yet another level beyond that: The GMC HUMMER EV 3X Pickup and SUV have three electric motors – one for the front wheels and two for the rear wheels, allowing each rear wheel to be driven independently.
For Drennen, each new capability is a “lever to pull” – a way to feed more precise data into a car’s computer system, offering faster and more accurate responses to changing driving conditions. “All of the sensors we’re using are getting more and more advanced, and those give us confidence to help keep the vehicle under control,” he says.
In Drennen’s view, today’s systems could never have been imagined by the engineers who created Max Trac. However, their early work on the world’s first traction-control system laid the foundation for decades of advanced technology to come.
You may have never thought about traction control, but for years, it’s helped keep your vehicle on the straight and narrow. In essence, a traction control system maintains vehicle control by reacting when the tires spin faster than the vehicle’s speed of travel. In slippery conditions, the system can help the driver maintain control.
Traction control is standard in every mainstream new car for sale today, and 55 years ago, GM helped pioneer the technology.
The 1971 Buick Riviera is best known for its bold boat-tail styling, but the coupe also debuted a revolutionary piece of technology: Max Trac, the world’s first computerized system to detect and help prevent wheelspin. Max Trac was elegantly simple in execution, but remarkably forward thinking.
The Riviera was a rear-wheel drive vehicle. Using speed sensors, one on the front wheels and one at the transmission, the Max Trac computer could detect any difference between the two. If the rear tires were spinning faster relative to the front wheels, the Max Trac computer would send a signal to the engine to reduce power, helping to bring the rear wheels back under control.
Max Trac was available as an option on the 1971 Riviera and expanded to the entire Buick full-size car lineup in 1972. Max Trac debuted six years before the first home computers hit the market. For many Buick owners, Max Trac might have been the first computer they ever bought.
In the half-century since Max Trac debuted, the creation of more capable computers and sensors has allowed GM engineers to refine traction control to a degree once thought impossible.
Anti-lock braking systems (ABS) use speed sensors at each wheel, giving a highly accurate picture of what’s happening at all four tires. Electronic engine management systems allow more precise control over the power being sent to the wheels. These modern developments give GM engineers highly advanced ways to improve traction control, detecting and responding to wheel slip faster and more accurately.
“It’s about giving you optimized wheelspin to keep the vehicle stable while preserving momentum,” says Arthur Drennen, GM Vehicle Performance Owner for Stability and Chassis Controls. “It lets you drive through what you need to drive through.”
Snow is a good example. On Max Trac-equipped Buick models of the early 1970s, the owner’s manual suggested turning off Max Trac when stuck in deep snow, as the system would reduce power and wheelspin that could help a driver get un-stuck. In modern GM vehicles, drivers rarely find themselves needing to turn traction control off to deal with situations like this. “It’s much better at keeping torque in the system,” Drennen says.
The advent of traction control enabled the creation of another system: Stability control, which helps prevent a vehicle from skidding or losing control while driving around a slippery curve. Since 2012, the U.S. government has mandated that all vehicles sold in America come equipped with stability control. In GM vehicles, traction and stability control are integrated into one system called Stabilitrak.
“With stability control, you have a steering-wheel angle sensor and an inertial measurement unit (IMU),” Drennen explains. “So, from the steering-wheel input, we know the path the driver wants to take, and from the accelerometer in the IMU, we know where the vehicle is actually headed.”
If the system detects a difference between where the driver wants to go and where the vehicle is headed, Stabilitrak can adjust the brakes, propulsion system torque, and all-wheel drive system (if equipped) to help the driver regain control. “The traction control system has grown from purely a power-reducing system to more of a torque distribution system,” Drennen says.
With the advent of user-selectable drive modes, drivers can tailor the traction and stability control system’s performance to a specific use case. Many high-performance vehicles offer a “track mode,” and off-road-focused vehicles include settings for sand or mud. On many family vehicles, Snow/Ice mode tailors the vehicle’s traction and stability control systems to help with confidence in slippery conditions.
EVs take traction and stability control to the next level. In an internal-combustion vehicle, Stabilitrak evaluates road conditions hundreds of times per second; in an EV, Stabilitrak can effectively infer road condition thousands of times per second.
That’s a wonderful capability unlocked by electric motors, which use sensors to precisely capture the exact position of the rotor that powers the wheels.
“We can look at the how fast the motor is accelerating, and in the case of wheelspin, determine that the motor is spinning up too fast to represent real tire grip,” Drennen explains. “Then we can reduce motor torque almost instantaneously.”
In a vehicle with an internal-combustion engine, the system first has to detect wheelspin before traction control can do its job by reducing engine power; in an EV, traction control starts working before undesirable wheelspin ever occurs.
All-wheel drive EVs, which have independent motors powering the front and rear wheels, offer even more control, allowing for precise torque output at both ends of the car. There’s yet another level beyond that: The GMC HUMMER EV 3X Pickup and SUV have three electric motors – one for the front wheels and two for the rear wheels, allowing each rear wheel to be driven independently.
For Drennen, each new capability is a “lever to pull” – a way to feed more precise data into a car’s computer system, offering faster and more accurate responses to changing driving conditions. “All of the sensors we’re using are getting more and more advanced, and those give us confidence to help keep the vehicle under control,” he says.
In Drennen’s view, today’s systems could never have been imagined by the engineers who created Max Trac. However, their early work on the world’s first traction-control system laid the foundation for decades of advanced technology to come.
Check out our past installments of GM Firsts: