Spinning knowledge on traction control
Standard safety feature helps drivers avoid skids that could result in crashes
Traction control technology became a mandatory feature on all passenger cars and light trucks in 2012, and the driving community is all the safer for it.
Traction control is an electronically controlled feature that limits wheel spin during acceleration so that the drive wheels maintain maximum traction and a driver maintains better control of the car.
In wet or slippery conditions, some wheels on your vehicle may start spinning faster than the others and the system’s goal is to reduce power to the excessively spinning wheel(s) when sensors detect it and redistribute it to the wheel(s) that may need more.
Most traction control systems now go the extra mile and use a vehicle’s anti-lock braking to slow a spinning wheel as power is being redistributed to other wheels. The main goal here is to avoid a skid, which could easily end in a crash if drivers don’t know how to control it.
“Traction control systems were traditionally mechanical and usually limited to the rear axle (2WD) with a limited slip differential to control power distribution,” said Rob Dexter, product and technology specialist at BMW Group. “There was a time when traction control was a standalone concept in the BMW world. However, since the introduction of electronic control systems, we have tended not to refer to traction control in isolation from our sophisticated Dynamic Stability Control system.”
Traction control is not a lesser version of Dynamic Stability Control, which controls oversteer and understeer conditions through a steering sensor and a control module that determines how much engine power gets to the wheels. Both systems work seamlessly together to provide total vehicle control in varying driving conditions and a safety net if something were to go wrong due to the loss of traction.
Traction control begins the process of staying in control, but stability control goes a step further by ensuring a vehicle stays on the intended path chosen by the driver.
“Traction control is, of course, a fundamental operating principle of BMW’s all-wheel-drive system, which works seamlessly with its sister Dynamic Stability Control (DSC) system to ensure optimum traction in all driving scenarios. However, controlling traction in the interest of forward motion is only one feature,” Dexter says, adding that the systems can do much more than just keep you safe.
Electronic technology in vehicles has advanced so much, and traction control in modern cars is now integrated with other safety systems that make the car safer and prevent a vehicle from losing control.
“Our system, through traction control, uses the brakes to slow a spinning wheel, then modulates engine power through throttle control and, finally, transfers power to other wheels,” says Andrew Parravano, product expert at Volvo.
“Some Volvo models, such as the S60 and V60 Polestar’s traction control system, has a reduction function that allows a longer time before the system intervenes.”
Similar systems, which are available in many performance-oriented cars, allow more rear-wheel slip when a driver decides to drive more dynamically. More rear-wheel slip will be allowed by the system as long as steering control by the driver is not too excessive, in which case the reduction function will automatically turn off.
This can be important for customers of performance vehicles who may not appreciate traction control systems inadvertently cutting engine power when these vehicles are being pushed to their limits.
Plus, drifting and letting the back end slide out (which traction control inhibits) is a much more fun way to get around a track. In a lot of performance cars, “Track Mode” turns off the traction control for drivers who prefer little to no intervention. There may have been a world where all this may not have even existed had it not been for the genius of Frank-Werner Mohn, a MercedesBenz engineer. A fateful car accident in 1989 inspired him to start developing the first iteration of stability control technology. Despite his car having well-functioning brakes, it was not enough to stop his car from skidding and he ended up crashing on the side of a snowy countryside road. By 1991, Mohn’s final version of his skid control technology had been approved for production in Mercedes-Benz vehicles.
One of the defining characteristics of Mohn’s design was for the system to be active at all times so that it prevents skids and loss of control before it occurs instead of reacting to a situation after it happens.
Fast-forward to the present and we are still seeing the positive effects of that technology on the safety of motorists and pedestrians alike. A 2015 U.S. National Highway Traffic Safety Administration (NHTSA) report confirmed that 6,169 lives have been saved by electronic stability control technology and the number will keep growing as this technology keeps improving.