Collision danger lurks from the side and in front of the vehicle. Blind spot and lane change warning systems offer assistance in detecting approaching or overtaking vehicles. Forward collision-warning systems alert the driver of obstacles in front of the vehicle. A number of Japanese vehicle manufacturers (e.g. Nissan, Mitsubishi) have announced the near-term availability of such collision warning systems for passenger cars.

Safety is especially crucial when a collision is practically unavoidable and there is no time left to warn the driver. In such emergencies, future driver assistance systems will execute vehicle control measures which either avoid collisions altogether or at least minimize their impact. While it will certainly take a lot longer for such „active“ safety systems to reach the market place, some premium vehicles, like the Mercedes-Benz S class, already feature an emergency brake assistant, which provides an additional braking force during the four-tenths of a second from the time that the foot hits the pedal till the time the brake pressure reaches the maximum working level. Currently, these types of devices reduce only one-tenth of a second of the braking lag, allowing to reduce speed by 5 km/h in most cases. This is quite valuable in itself, but in combination with a sensor-based system which detect collisions ahead of time, future safety systems stand to gain significantly in reduced collision speeds.

Further down the road are collision avoidance systems which act differently in the time leading up to a collision, depending on the type of object that is about to be hit. Special care will be given to pedestrians and other vulnerable road users; protective measures might include the deployment of extensible structures at the vehicle front (bumper, motor hood) to minimize pedestrian leg and head impact. The European Union (EU) is actively sponsoring research in this area, among others in 5th Framework  projects PROTECTOR and SAVE-U.

© Autoliv

But driver assistance systems also promise to increase convenience and comfort by relieving the driver from tedious parts of driving. Conventional cruise controls, which maintain a preset speed, appeared more than twenty years ago. More recent generations involve so-called adaptive cruise controls (ACC), which maintain a constant safe distance to the vehicle in front, automatically slowing down if the vehicle in front slows down, and automatically speeding up if the vehicle in front picks up speed. In the event that the vehicle in front makes a lane change or speeds away, the own vehicle accelerates till it reaches a preset cruising speed of the conventional cruise control. ACCs are perhaps the most visible exponent of sensor-based driver assistance systems nowadays. They are available as an option on most premium vehicles (e.g. Mercedes-Benz S-Class, Jaguar XKR and Lexus LS430). By 2002, Fiat plans to make it available in its mid-range Punto model.

Current ACCs only work in free-flowing traffic conditions on the highways. Over the next few years, their operating range will be extended to the lower speed range, to include bumper-to-bumper, Stop&Go (SG) traffic. Much further down the road - and the focus of research at vehicle manufacturers such as DaimlerChrysler - are cruise controls which can operate in the very complex urban traffic scenario. These sophisticated cruise controls will not only pay attention to the vehicle in front but also take into account relevant elements of the traffic infrastructure (e.g. lanes, traffic signs and traffic lights) and other road users (e.g. pedestrians, bicyclists, mopeds, vehicles).

© DaimlerChrysler

Finally, driver assistance promise to increase traffic efficiency. This by allowing trucks in the future to participate in „electronic tow-bar“ configurations, where the leading truck is driven manually, and all others automatically. This not only saves manpower, but also fuel, thanks to the reduced distance between trucks in the platoon that are acceptable and the improved wind cover. It might even increase traffic throughput. Initial results were successfully demonstrated in the EU project CHAUFFEUR.

A variety of sensors vie to provide the eyes and ears of driver assistance systems: video cameras, radar sensors (77 GHz / 24 GHz), laser scanners, ultrasound devices. In particular video sensors are a natural fit, given that they provide texture information at very fine angular resolution, facilitating the high degree of discrimination necessary for object recognition (e.g. lanes, vehicles, pedestrians, traffic signs, traffic lights). The human visual perception system is a good example of what performance might be achieved with such sensors, if only the appropriate processing is added. By using a complementary set of sensors, however, system reliability and accuracy can be improved. In particular the radar- and video-combination is under active consideration. Finally, cooperative safety systems, involving vehicles which communicate and coordinate responses among each other, could one day close any remaining perceptual gap of the sensors.

Apart from the technical challenges of developing driver assistance systems, questions remain how they will affect the driver. Will the driver still be alert enough to intervene and take over control from a semiautomatic system when required ? Will he drive more reckless because he comes to rely on the driver assistance systems? All these issues remain to be examined, case by case. One thing is sure, the fully autonomous vehicle is still very far away - till then -

Consider yourself firmly in the driver seat!

IV Articles in Media

Intelligent Vehicles Links

• IEEE Intelligent Vehicles Symposium 2009
• Richard Bishop’s IVsource Site
• IEEE Intelligent Transportation Systems Council (ITSC)

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