Mercedes-Benz Safety Systems for Tired Drivers
Official statistics cite tiredness as the reason behind around one percent of all serious traffic accidents. However, experts believe that the number of unattributed cases of this type of accident is significantly higher, as tiredness is often a factor which is impossible to ascertain or prove when reconstructing the accident. According to the latest European studies, 24 to 33 percent of all fatal traffic accidents involve overtired drivers. This means that tiredness is probably responsible for a higher proportion of serious traffic accidents than alcohol.
In addition to the lack of a good night’s sleep, one of the most frequent causes of the dangerous phenomenon of nodding off at the wheel is monotony. Two thirds of accidents caused by tiredness occur in the dark, half where there is little traffic around. Scientists believe that the risk of accident is particularly increased on long-distance journeys under unchanging conditions, as this causes the driver’s attention to tail off and the monotony also increases the risk of falling asleep.
Investigations by Mercedes engineers involving over 420 car drivers to date show that many people fail to recognise the signs of tiredness or do not spot them at an early enough stage. Tiredness does not generally make itself felt in sudden bursts – it gradually builds over time. The driver’s reactions and perceptual capacity gradually diminish to such an extent that, even in the early phases of tiredness, drivers are often unable to react appropriately.
The assistance system developed by Mercedes-Benz is designed to detect the early signs of tiredness and warn the driver. It will therefore make an important contribution to the prevention of accidents.
Individual driver profile based on various indicators
Unlike other methods of detecting tiredness, the Mercedes system evaluates a
series of indicators in order to assess the alertness of the driver and to recognize the gradual transition between being awake and being tired. During every journey Attention Assist continuously observes the driver’s typical behavior patterns and uses these to create an individual driver profile which serves as a basis for recognizing the symptoms of tiredness. Where there is a significant deviation from the saved empirical values, the system determines whether or not there are signs of encroaching tiredness. Whether and when the driver is warned also depends on the time of day, the duration of the trip and the individual’s driving style.
Steering behavior as the key indicator of tiredness
The values recorded by the tiredness recognition system not only include the speed and the longitudinal and lateral acceleration but also the angle of the steering wheel, the way that the indicators and pedals are used, certain driver control actions and various external influences such as a side wind or an uneven road surface. Observation of the steering behavior has proven particularly significant: tired drivers can be spotted by a series of typical steering wheel movements which they then immediately correct. The new Mercedes assistance system recognizes signs such as these; if the driver’s steering behaviour changes and other indicators also point towards encroaching tiredness, the system outputs a warning at an early stage. A warning signal sounds and a symbol in the instrument cluster advises the driver to take a break.
Over 500,000 kilometers covered to date in worldwide tests
The development of the unique assistance system began with a series of experiments in the driving simulator in Berlin. These were followed by daytime and night-time motorway trials. Over 420 test people have taken part in these to date and so far they have covered a total of over 500,000 kilometers. The test program for Attention Assist will be rounded off with long-term trials in various climate zones, in city traffic, on poor roads and on long-distance trips. The Mercedes development team not only includes engineers but also cyberneticists, mathematicians, computer scientists and psychologists.
Complementing the familiar driver assistance systems
When developing driver assistance systems, Mercedes-Benz has always focused on real accident data and develops technologies which are designed to improve driving safety in critical situations. The focus to date has been on those accidents with particularly serious consequences: front-end collisions, rear-end collisions, night-time collisions and accidents involving pedestrians. Attention Assist continues Mercedes-Benz’s practice-oriented commitment to preventing accidents and complements familiar driver assistance systems such as ABS, Brake Assist, Brake Assist PLUS, PRE-SAFE® brake, the infrared nightview system and ESP®, which monitor the vehicle and its surroundings. The tiredness recognition system is the first technology to observe the driver on a continual basis too and to use typical behavior patterns to detect the risk of an accident and provide a warning. Series production of the system is planned for 2009.
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