Antilock brakes and beyond
Imagine coming up over a hill at full speed and seeing an animal in the middle of the road. What’s the best way to react? Before the introduction of antilock braking systems (ABS), hitting the brakes would give you full stopping power but no steering ability. Not hitting the brakes would give you full steering ability but no stopping power. Antilock brakes give you the best possible stopping power with the best steering ability.
ABS is an automated system that uses cadence braking to prevent our wheels from locking up and helps avoid uncontrolled skidding. It does this with more control and much faster than any of us could possibly do on our own.
To quote the National Highway Traffic Safety Administration:
“ABS works with your regular braking system by automatically pumping them. In vehicles not equipped with ABS, the driver has to manually pump the brakes to prevent wheel lockup. In vehicles equipped with ABS, your foot should remain firmly planted on the brake pedal, while ABS pumps the brakes for you so you can concentrate on steering to safety.”
ABS makes use of wheel speed sensors that can tell if one or more of your vehicle’s wheels are trying to lock up while braking. If one of your wheels does try to lock up, hydraulic valves limit or reduce the braking on that wheel. This helps prevent you from skidding and allows for more steering control.
ABS offers much more control and decreases stopping distances in most situations. However, on snow or gravel roads it can increase braking distance, but will still improve steering ability. Some vehicles have an off-road button to turn the ABS functions off.
Even though the word braking is in the name, the primary purpose of ABS is to give you steering control over your vehicle after heavy braking.
These systems have improved consistently since they were first introduced. Newer versions not only prevent your wheels from locking, but can also control other aspects of driving. Depending on how they are implemented and their capabilities, these systems are then known as, electronic stability control (ESC), electronic brake force distribution (EBD), and traction control. They all essentially use the same sensors and components as ABS.
ESC helps you stay in control of your vehicle when you need to swerve or brake suddenly to avoid an obstacle, like an animal in the middle of the road. ESC measures yaw or rotation (like on a plane). Yaw is the rotation around the vertical axis, or the spinning left or right. When the direction of your vehicle does not match your steering, ESC will automatically brake one or more of your wheels for a short period of time, reduce your engine power, or both. This helps keep the vehicle going in the direction you want and helps keep it in control.
ESC is normally on when you start your vehicle. Some vehicles have a manual ESC Off switch for certain situations such as when you are stuck in snow.
Electronic brake force distribution (EBD) realizes that some wheels carry a heavier load than others and will require more braking to avoid losing control when bringing your vehicle to a stop. It detects this need instantly and continually changes the amount of braking power sent to each wheel.
Traction control helps you accelerate on slippery low-friction surfaces like snow, ice and loose gravel. It does this by applying the brakes to a wheel or wheels that are spinning faster than others. Applying this braking action to the spinning wheel transfers power to the wheel with traction. Traction control systems are usually a secondary function of the electronic stability control and is activated when throttle input and engine torque don’t match road conditions.
Studies show that by helping you to steer, these systems have helped to decrease frontal crashes. Some reports show a 35 per cent decrease in front crashes on wet roads and a nine per cent decrease on dry roads.
In controlled tests, 58 per cent of drivers without ABS did not stay on their intended path while braking. With ABS only 24 per cent did the same.
Even given these stats, there are questions around these systems as to whether they allow drivers to just adapt to these safety benefits and then drive more aggressively. Obviously the idea of these systems is to add safety to your driving, so hopefully this is not the case.
The idea of defensive driving is not only to save you from potentially fatal crashes but also to save time and money.