The eyes in the camera and the radar take the strain off the driver when driving at night or in stop and go traffic

Sep 8, 2008

Tired and inattentive drivers run the risk of swerving off the road or of being involved in rear-end collisions in monotonous stop and go traffic or hazardous situations when overtaking. Lane Departure Warning (LDW), Adaptive Cruise Control (ACC) and Blind Spot Detection (BSD) make driving safer and more comfortable.

Berlin/Frankfurt am Main, Germany. Sleep creeps up on you almost unnoticed: at the end of a long drive back from your holiday or after a stressful, tiring day at work, you are notoriously at risk of falling asleep for a few seconds. The driver nods off for an instant and unfortunately the consequences are not always just damage to the bodywork. Tiredness is a factor in roughly one in four serious accidents; particularly at night when the risk of an accident is twice as great as by day. The Lane Departure Warning (LDW) driver assistance system, developed by Continental, the international automotive supplier, alerts the driver before his vehicle is about to leave the lane. The system is installed in passenger cars but is also ready for series production use in trucks. Truckers are especially at risk, spending long periods at the wheel without a break; veering off the road is one of the most frequent causes of accidents. According to a study carried out on behalf of the Federal Ministry of Education and Research, LDW could prevent just about half of the accidents caused in this way.

The centerpiece of this intelligent driver assistance system is a camera, installed close to the rear-view mirror, and which is directed forwards at the road markings in front of the car. The camera's electronics analyze the images and calculate whether the car is about to depart from its lane. The driver's attention is drawn to this danger, typically by vibrations in the steering wheel or by gentle steering interventions. This “electronic co-driver” works in the background and only gives a warning if the driver appears to depart from the lane inadvertently if he operates the turn indicator the warning is suppressed.

Lane Departure Warning (LDW), Adaptive Cruise Control (ACC) and Blind Spot Detection (BSD) make driving safer and more comfortable. Blind Spot Detection (BSD): looking into the blind spot

A quick look at the inside and outside mirrors, perhaps even a fleeting glance over the left shoulder and then a major fright when there is loud hooting from your left as you pull out to overtake. Failing to see the car approaching rapidly from behind in the left-hand lane or in the blind spot next to your own car easily happens, especially in heavy traffic on multi-lane freeways or highways and in urban traffic as well. The Blind Spot Detection (BSD) system developed by Continental to monitor this area can take much of the strain off the driver and avoid hazardous situations. Radar sensors monitor the road area behind and next to your own vehicle and sound the alarm if you try to pull out despite there being no gap. How the driver is warned is a matter for each vehicle manufacturer's design philosophy; but the essential element is a display near the outside mirror.

Adaptive Cruise Control (ACC): Automatic safe vehicle spacing even at high speeds

Speed is not dangerous in itself. But it becomes so if vehicles follow each other too closely. Essentially, the “half speedo reading” rule of thumb applies; this says that the distance in meters from the vehicle in front should be half its speed. At 100 km/h that would be 50 meters. Heavy traffic rapidly reduces the available safety distance. At 100 km/h a vehicle covers some 28 meters every second. The average driver needs at least a second to become aware that the vehicle in front is braking, take his foot off the accelerator, place his foot on the brake pedal and push down hard. That easily amounts to 40 meters before the brakes fully take effect. If the driver in front has braked at full strength but the driver behind has not, then a rear-end collision is inevitable.

Adaptive Cruise Control (ACC) reduces this risk. Like any standard cruise control system, it maintains a constant chosen speed by easing back when going downhill and increasing power uphill. However, in addition, it uses its radar or infrared sensors to monitor the traffic in front. Before you get too close to the vehicle in front, ACC either reduces engine power or gently applies the brakes until the gap is again appropriate. If the vehicle in front speeds up or moves out of your lane, ACC automatically accelerates until the cruising speed previously set is reached. Occasionally, for example if the vehicle in front brakes sharply, gentle braking by ACC will not by itself be sufficient; in such cases, the driver assistance system will also request the driver to apply the brakes himself.

Even when ACC is not active, it provides a safety bonus. If a rear-end collision appears imminent, the sensors can alert the driver in good time and begin raising the pressure in the braking system. This will allow the brakes to respond more rapidly in an emergency when the driver steps on the brake pedal. As a result of the reduced speed, the consequences of the accident will be less serious or it may even be possible to avoid a rear-end collision altogether and this will also avoid the mile-long traffic jams which waste valuable time and gasoline, and produce CO2 emissions. As well as their safety benefits, driver assistance systems can also help to save money and penalty points because failing to observe correct vehicle spacing even when it is entirely unintentional will be penalized significantly more severely in future.

The latest ACC systems also help in slow-moving traffic or traffic jams and, if necessary, can brake vehicles until they are fully stationary. If the sensor then reports “road ahead clear”, the driver can reactivate the system and carry on with automatically controlled stop and go driving – this can even banish the “horrors” of rush hour traffic.

Press Release (MS-Word, 60 KB)

Press Image to the issue Lane Departure Warning in the Continental Media Center.

Nicole Geissler

External Communications


Division Chassis & Safety

Guerickestraße 7

60488 Frankfurt am Main

Phone: +49 69 7603-8492

Fax: +49 69 7603-3945