By Jim Kerr
Wet, snowy and icy roads are not far away; in fact, in some parts of the country they are already here. Traction is limited and even with winter tires, drivers need to adjust their driving style by reducing speeds, increasing following distances and avoiding hazardous conditions when possible. The auto manufacturers are helping us too, with ABS, traction control and stability control as standard equipment on most vehicles. Even subcompact, economy cars usually come with these features. These systems are continually improving but they still have limitations. Let’s take a look at how they help both inexperienced and experienced drivers.
ABS (Anti-Lock Brake System) has been available for nearly three decades. Today’s systems often include Brake Force Distribution and Brake Assist features as well. The ABS system is designed to keep the tire rolling in contact with the road, as a tire that is locked up has less traction than one that is rolling slightly. There are a couple exceptions, such as deep gravel or deep packed snow where a helpful wedge actually builds up in front of a sliding tire. Another advantage of keeping the tire rolling is you maintain steering control: with ABS, you can simply press hard on the brake pedal and steer around an obstacle. In the heat of the moment, many drivers forget about steering but it is often a choice than can prevent a collision.
Brake force distribution is an electronic program that balances the braking effort between the front and rear wheels. The shortest braking distance is obtained when there is balanced braking, but weight transfer from the rear to the front of the vehicle during braking constantly changes this balance. The electronic program compensates for weight transfer. Without it, you may have one end of the vehicle overbrake, which can cause a skid.
Brake Assist also helps drivers. When a sudden braking situation occurs, drivers may react quickly but often don’t push the brake pedal hard enough for maximum braking until a second or two later. Brake assist senses the quick brake pedal application and will automatically apply full braking so the ABS can do its job. Release the pedal and the Brake Assist stops too.
Traction control also keeps the tires in contact with the road by limiting wheel spin during acceleration. A warning indicator on the dash signals the driver when traction is poor so they can release the accelerator, but in the meantime the system automatically tries to prevent the wheels from spinning. This works great and can be a huge safety feature, especially if driving on roads where there are intermittent patches of ice.
Traction control is also part of the stability control operation. By adding some steering wheel position, lateral acceleration and yaw sensors to the vehicle, the computer can now detect whether the vehicle is going in the direction the driver intended. If the vehicle starts to slide or spin, the computer can activate a combination of ABS and traction control to try and bring the vehicle back into the chosen path. By braking one front wheel, or in the case of Acura’s Super-Handling AWD system, accelerating one back wheel, the vehicle is turned to maintain control. Power from the engine may be reduced if necessary, and some cars are even starting to use electric steering systems to add in steering assist to help control the car.
All these systems work faster than you can blink your eye, so they react to potential loss of traction situations before the vehicle spins. There are some limitations, however. If you think you are a race driver, the system will get you around corners (not the fast way though), but push it too hard and even the electronics won’t help if the tires can’t grip the road because of too much lateral slip. Freezing rain can make road conditions so slippery that nothing will help. The tires have to have some traction in order for these systems to work.
While ABS, traction control and stability control are great safety features and truly help both inexperienced drivers and inattentive drivers – we all drive at less than full alertness sometimes – they can’t overcome the laws of physics. Keep good tires on your vehicle, slow down, drive smoothly and cautiously. It will help avoid an accident or a trip into the ditch and as a bonus will improve your fuel economy too.