How Drive-by-wire Technology Works

Benefits and Drawbacks of Drive-by-wire Systems
Although drive-by-wire offers many benefits to car systems, concerns over reliability have stalled its full acceptance.
Although drive-by-wire offers many benefits to car systems, concerns over reliability have stalled its full acceptance.
AP Photo/Andree-Noelle Pot

Some people are excited about the prospect of more drive-by-wire systems in cars. By replacing conventional throttle systems, drive-by-wire systems can significantly reduce the number of moving parts in a vehicle. This reduces weight, increases operational accuracy and stretches out the time between service visits for things like mechanical maintenance and other adjustments. Some by-wire systems wouldn't even require service at all. Less weight and better accuracy would equal better fuel efficiency and fewer emissions, too.

Sounds great, right? Well, although it's well-established in the airline industry, drive-by-wire has been slow in its introduction to the car. The problem for some car manufacturers is in convincing drivers that the systems are safe. Because of the complexity of drive-by-wire systems, some people worry about potential electronic malfunctions in sensors and computers, leading to vehicle damage or even car accidents and passenger injury.

One argument against drive-by-wire is that any system using software has the ability to fail regardless of how many times that software has been tested. In a worst-case scenario, for example, the sensors on a brake-by-wire system could make an error in calculation, causing the brake caliper and pads to apply an incorrect amount of pressure -- either too light or too strong -- to the rotor. Unaware of any internal system problems, the driver using the brake-by-wire system could potentially get into an accident, even though he or she thought the correct amount of pressure was being placed on the brake pedal.

In any case, most people refer to the saying that any software is only as good as the programmers and manufacturers who built and designed it. Because of the reliability of fly-by-wire in airplanes, it's likely that experience and product testing could bring more drive-by-wire systems safely to everyday cars. Several car companies are already using (or have used) various drive-by-wire systems in use their vehicles, including BMW, Mercedes-Benz, Land Rover, Toyota, GM, Volkswagen and Nissan.

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