How GPS can stop you skidding

Weather forecasting on the move

WE’VE ALL BEEN there: a dark winter night, temperature around zero, driving on an unfamiliar country lane, when suddenly the wheels lose traction and, for one heart-in-the-mouth instant before the ESC kicks in to correct the slide, you’re heading for a tree. Black ice and other weather-related hazards are real killers.

But what if your car knew there was a chance of black ice on that road and had warned you and prepared the car’s safety systems in anticipation of such a drama? Engineers at tech supplier Continental are developing Road Condition Observer.

It’s made possible by the ever increasing sophistication of sensors and cameras, combined with the ability to stream data in a car. That, and the engineers’ ability to write sophisticated algorithms.

Camera images from the front of the car are cross referenced with tyre behaviour and vehicle dynamics data from the ESC, as well as local and regional weather data, making it possible to calculate the grip co-efficient of the road surface.

The initial input is from a digital weather map downloaded from the closest meteorological station, determined by the car’s GPS. Then, by combining temperature, humidity and air pressure, the system calculates the dew point and how much the air needs to cool before it starts raining or snowing. By using the image from the camera, an algorithm determines if the road is currently wet, dry or damp by recognising specific characteristics like mirroring or colour.

Simultaneously, an infra-red laser mounted in the front bumper measures the varying amplitude of light reflected off the road surface immediately ahead of the tyres. And the ABS determines the difference between smooth and rough surfaces.

All that knowledge is then deployed to tweak the assistance systems and, if necessary, apply automatic emergency braking much earlier than would otherwise be possible. It’s like having your own personal weather forecaster and rally co-driver on board. Eventually, when vehicle-to-vehicle communications is common, the system will also be able to warn other vehicles of impending bad weather.