Automatic Traction Control (ATC) and Anti-lock Brake System (ABS) are a pair of great modern safety features on many modern automobiles that will give less-than-fully attentive drivers a chance to recover from a driving mistake. These systems prevent your tires from skidding, which in turn allows the tire to maintain as much traction as possible. And with that traction, the driver can stop or steer the car away from danger.
ATC and ABS both use a system of sensors in each wheel of your car that is linked to central computer. The computer compares the rate upon which each wheel is turning. If the computer senses enough difference in the rate that wheels are turning, it will send signals to the either the engine (for Traction Control) or the brakes (for Anti-lock Brakes) to keep the tires turning no matter how slippery the road or how hard you mash on the brakes.
In the top levels of auto racing, primarily in Europe and Asia, ATC and ABS combined with very sophisticated automatic transmissions are incorporated in the design of racecars to wring the last bit of speed out of the cars. But all that technology is complicated and expensive so race organizers who want to keep costs down for competitors outlaw this technology.
So this ATC and ABS stuff is great right? Well when it works, it is pretty darn good. For the average inattentive driver on the cell phone, it could be the margin of safety that prevents an accident. Personally, I am of the opinion that an attentive driver who drives within the limits of the car, the road and his own abilities does not need all this "nanny" technology for normal driving. And I have seen reports that ATC and ABS can be a disadvantage in gravel and snow. Apparently, being able to lock up the tires on those surfaces allows a "wedge" of gravel or snow to build up in front of the tires and facilitate stopping.
OK, so most of the time ATC and ABS are great. And I would not avoid buying a car because it has this technology. But sometimes the ATC and ABS lights will light up on your dashboard for no apparent reason. And in some circumstances, you will feel the Traction Control "grip" your wheels to prevent slippage when you are on a dry surface. Why would this happen?
It is not unknown for this mysterious bad behavior by ATC and ABS to be caused by tires that have worn unevenly or just have different air pressure. If your tires are approaching the end of their usable tread, there could be enough slippage to set off the systems. And you can imagine the havoc that would be played with the system if you put miss-matched tires on your car. So if your car is alerting you to ATC and or ABS activity when you do not think it should be, check your tires for wear or uneven inflation.