SensorCar

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    Mazda has been involved in this project some time, having participated in the Study Group for Promotion of the Advanced Safety Vehicle which was established by Japan’s Ministry of Transport some years ago. Mazda’s proposal uses a 626 model and focusses on advanced technologies that help minimise injuries to occupants during a rear-end collision as well as to alert drivers to pedestrians walking across the road ahead.

    Such technology is very much needed as in many countries, pedestrians account for a significant proportion of traffic accidents. Analyses point to a major cause being the lack of awareness by drivers who fail to spot a pedestrian in front until it is too late to stop. This is even more significant at night and in poor lighting conditions.

    The SensorCar has a laser radar unit mounted in the front end which sends out signals. Reflections are analysed by a computer and the system can differentiate between people and inanimate objects like trees or barriers. Tests have shown it to be able to detect a pedestrian crossing the road at a range of 45 metres – 60 metres, depending on the reflectivity of the clothes worn (white reflects better).

    The computer does its analysis on the basis of distance, vehicle speed and also the direction of travel in relation to the vehicle. Thus, if the pedestrian walks across the road while the car is idling at a junction, no alert will occur. But if there is a potential for an accident, an alarm sounds inside the car and a light flashes on the instrument panel. The horn will also sound automatically if the distance to the pedestrian is very short and hard braking is needed to prevent an accident.

    But at this time, no automatic braking is programmed into the system. This is probably because it can be dangerous if all other vehicles do not have auto-brake systems as well. Furthermore, until the reliability of computerised systems is 100% bug-free, it could be more dangerous to allow a computer to hit the brakes!

    “According to estimates based on data from the Japan Automotive Research Institute, such a system could reduce pedestrian injuries by half and pedestrian deaths by up to 90%,” said Kazuki Fujise, a Mazda researcher.

    A second feature of the SensorCar is a rear impact sensor. Two sensors in the rear bumper constantly monitor traffic at the back of the car and analyse whether a collision is about to occur. If the system determines that a significant rear impact is going to occur – a situation where the car behind is closing in at 10 km/h or faster – an alarm sounds and a warning light flashes to alert the occupants. In the next instant, the front seatbelts automatically tighten to reduce the distance the occupants will be moved backwards on impact. By having their bodies closer to the backrest and the head restraint, neck injuries can be reduced.

    The system works whether the car is stationary or in motion but a lot of work has gone into programming to false alarms. “We believe that in future, similar technology could be applied to systems to recognise side and front collisions as well,” said Mr Fujise.

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