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Intelligent cars avoid accidents

10 August 2009

The aim is that tomorrow's cars should quite simply be able to avoid accidents. Many of today's cars are already so intelligent that they alert the driver or even step in and brake the car to avoid an accident.

Have you ever felt drowsy while driving and almost dozed off behind the wheel? If so, you are not alone in answering "yes" to that question.

Drowsy drivers cause many accidents on roads the world over. Sometimes it may be difficult to ascertain if it is a tired driver who has caused an accident, so the true extent of the problem is largely hidden. What is clear, however, is that drowsy drivers are a large - and global - traffic-safety problem.

According to the American NHTSA (National Highway Traffic Safety Administration), about 100,000 accidents are caused in the USA alone by drivers falling asleep behind the wheel. As a result of these accidents, about 1500 drivers and passengers are killed and 70,000 are injured.

The situation in Europe is similar. German insurance organisation GDV's statistics reveal that about 25 percent of all fatal autobahn accidents are caused by tired or drowsy drivers.

Accidents outside cities more common
Sleep-related accidents occur more often outside cities than other single-vehicle accidents do, and just over 70 percent of all sleep-related accidents take place on roads where the speed limit is between 70 and 110 kilometres an hour (Anna Anlund, VTI, the Swedish National Road and Transport Research Institute, in Sweden).

Volvo Cars has developed technology that can alert a drowsy driver long before he or she dozes off behind the wheel. The system is called Driver Alert Control and it immediately registers if the car is being driven in a controlled way by monitoring how the vehicle moves between the painted road markings.

Driver Alert Control is aimed primarily at situations where the danger of losing concentration is biggest and where an accident would have serious consequences. This may for instance be on a straight, easy to drive and therefore monotonous stretch of road where the driver feels relaxed and the risk of dozing off increases.

Another common cause of accidents is distraction. A mobile phone may suddenly ring or the driver may drop something in the car and start looking for it. According to the NHTSA, distracted drivers are the cause of 40 percent of all run-off-road accidents.

Run-off-road accidents often fatal
Run-offs account for just over 20 percent of all accidents and almost 40 percent of all fatal accidents, according to US statistics (NTHTSA, 2003). Statistics from other countries also show that run-offs figure heavily in serious accidents.

In order to reduce the risk of run-off-road accidents Volvo has developed a system known as Lane Departure Warning which monitors the road via a camera fitted below the rear-view mirror. If a wheel accidentally strays beyond a lane marker, a warning signal automatically alerts the driver to respond.

Another system that can help reduce run-off-road accidents is Collision Avoidance By Auto Steering, which monitors oncoming traffic with the help of both cameras and radar. If the driver does not respond to the warning signal, the system boosts steering force to help bring the car back to its original lane.

The frontal collision is a difficult accident scenario that often leads to very serious consequences. In Germany, frontal collisions account for 5 percent of all accidents and a massive 20 percent of all fatal accidents.

Even when it comes to frontal collisions, Emergency Lane Assist can help reduce their frequency. This technology will be found in forthcoming Volvo models.

Rear-end collisions are common
Rear-end collisions are a common occurrence and account for 29 percent of all car accidents reported to the police in the USA. In about half of all rear-end collisions, the driver has not braked at all prior to impact.

These accidents, which often take place at low speeds, do not always lead to serious injuries but they can give rise to neck injuries which may be long-lasting and result in major costs to society in general. Here a new Volvo system known as City Safety, which is active up to 30 km/h, can help avoid or reduce the consequences of rear-end collisions.

City Safety helps avoid or reduce the consequences of a collision at low speed by automatically braking the car and at the same time restricting the throttle. In addition, the brake lights are activated to warn following traffic. City Safety is already fitted as standard on the new Volvo XC60.

The system is programmed to respond to vehicles in front that are either stationary or are moving in the same direction.

Based on the car's own speed and the gap to the vehicle in front, the system calculates the braking speed needed to avoid a collision. If the calculated braking force exceeds a given level without the driver reacting, the danger of a collision is regarded as imminent and the system automatically steps in.

Dangerous for Japanese pedestrians
One of the more common causes of accidents in our cities is pedestrians stepping straight out into the roadway. In the USA, more than 11 percent of all traffic fatalities are pedestrians and in Japan, this scenario accounts for about 30 percent of all fatal accidents.

Volvo Cars is currently working on advanced new technology to reduce or entirely avoid collisions with pedestrians in urban environments. The new approach utilises both radar and camera technology.

The aim is to identify pedestrians and alert the driver so that he or she can take the necessary action to avoid an accident. If the driver does not react in time, the system automatically brakes the car.

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