Traffic safety research indicates that only about 40 per cent of drivers involved in a crash applied the brakes. The majority do not even get their foot on the brake pedal, failing to identify the situation in time to take evasive action either due to distraction or by not looking far enough ahead.
This situation was first addressed by Mercedes-Benz about a decade ago when it developed a system that prepared the braking system for emergency stops. Further advances since then has led to a number of manufacturers offering systems that not only warn the driver of an imminent crash, but are capable of applying the brakes and bringing the vehicle to a stop – without driver involvement.
While passive safety devices like seat belts and airbags help reduce injuries after a crash has occurred, active safety features like ABS and electronic stability control, mandatory on all new passenger vehicles, are designed to help a driver avoid a crash. The new automatic braking systems are the latest of these active systems.
Offered under a variety of names, depending on the manufacturer, these "intelligent" braking systems that stop or at least slow the vehicle if the driver does not act are standard or available on a number of vehicles. According to the Insurance Institute for Highway Safety (IIHS), the following volume manufacturers sell 2013 model year vehicles equipped with forward warning and automatic braking systems: Acura, Audi, BMW, Infiniti, Jaguar, Land Rover, Lexus, Mercedes-Benz, Porsche, Subaru, Toyota and Volvo. You will notice that with the exception of Subaru and Toyota they are all high-end manufacturers. As is usually the case, new technologies first appear on expensive cars where the added cost is more readily accepted, filtering down as the cost drops with volume and advances in technology.
Some of these systems are capable of preventing crashes altogether while others greatly reduce the speed prior to the moment of impact – the effectiveness is directly related to the closing speed of the vehicles and or object. Low speed systems, the least expensive to develop and install, are extremely effective in crawling traffic or parking lot situations. It takes a whole other level of technology to thwart a head-on crash between two vehicles travelling at 100 km/h.
Most manufacturers have their own technology, whether developed internally or by a supplier. But they all depend on input from a variety of sensors – radar, video cameras, ultrasonic and even GPS technology. This information is analyzed to determine if objects in the path of the vehicle, fixed or moving, are a threat. Most systems depend on the same input and information used for active or adaptive cruise control systems, which determine if the speed of the vehicle is greater or less than that of the vehicle in front. If that input indicates a significant speed differential, resulting in a likely collision, the brakes are applied, without any driver input.
Primarily developed for collision avoidance, these systems commonly warn a driver of an impending crash through audio and/or visual alerts. Some will tighten the belts, others may shake the steering wheel and most will involve a warning buzzer to get the driver's attention. They will then pre-charge the brake system and, if necessary, apply the brakes.
The technology and programming necessary involves everything from identifying and quantifying the objects, their size, location, etc., to "Transfer of Control" technology developed to determine when to take action if the driver has failed to do so.
The IIHS estimates these systems can prevent or lessen the impact in 1.9 million crashes a year – reducing injury to 66,000 occupants and the deaths of almost 900 others – in the U.S. alone.
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