ABS brakes have long been the standard in the auto industry and are found on every new vehicle. However, there was a time when this technology was considered revolutionary — it dramatically improved on-road safety and solved a problem that had long plagued drivers and engineers alike.
It’s amazing when a feature becomes so commonplace that its ability to save lives is completely taken for granted. The ability of anti-lock brakes to tame perilous driving conditions is impressive, but how exactly do they work when dealing with winter’s snow and ice?
Avoid That Lock-Up
Hitting your brakes hard enough to lock them up might seem like the fastest way to stop a car — similar to dropping an anchor as you drag your four wheels flat along the asphalt — but it comes at the expense of control. If the wheels aren’t turning due to lock-up, you have no way to safely steer your vehicle, which can mean the difference between avoiding a collision and bracing for impact. On some surfaces, too, a locked wheel slides a lot farther than one that’s braking more gradually and can still rotate.
ABS brakes were designed to prevent skids by keeping brake pad pressure right on the brink of lock-up but never crossing over that line. This is accomplished by using a set of wheel speed sensors that monitor the rotation of each tire relative to the vehicle’s speed. This information is then fed back to a computer controller that pulses brake pressure to each individual wheel by a series of valves attached to a pump — effectively replacing the pumping that used to be a staple of pre-ABS emergency stops, where human drivers had to perform all of the above calculations in the middle of a crisis situation.
Putting It All Together
How do ABS brakes work on snowy roads? When a deer jumps out in front of you, or the car in front of you brakes quickly, you simply don’t have the time or space to manually pump the brakes and stop safely without computer intervention. Instead, when you hit the brake pedal hard, the ABS system leaps into action.
First, the controller sends maximum braking power to each of the vehicle’s four wheels while it monitors speed sensor data to see if any of the tires are on the verge of locking up (which is represented by a sudden individual deceleration). Once detected, it backs off pressure before applying it again quickly, continuing to cycle through this pump-and-release strategy many times per second.
While this is happening, your vehicle is kept at the threshold of wheel lock-up, allowing you to steer while it slows down as rapidly as possible. You don’t have to think any of it through — just maintaining a steady pressure on the brake pedal allows the system to do its job while you keep your vehicle pointed in the safest possible direction.
ABS brakes have saved countless lives and have made winter driving that much safer, and more user-friendly, for beginners and experienced drivers alike.
Check out all the brake system parts and accessories available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on ABS brakes, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
Photo courtesy of Wikimedia Commons.
Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time. I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.