For emergency braking in front of vulnerable road users, cars use both radar and camera signals, as do other active safety systems. Sometimes they have to evaluate several inputs at the same time. That applies to the scenario depicted in the introduction, where a car approaches a stationary or slower-moving car from behind. Ideally, an emergency braking function would be activated in the car approaching from behind. “In this case, the car is able to apply the brakes when there is a difference in speed between the cars of up to about 60 kilometres per hour,” explains Petr Dudík, another developer of assistance systems.
Emergency braking in a situation where a car approaches another stationary or slow-moving car
However, Škoda cars also have a function that helps with evasive manoeuvres in cases like this. “If the driver’s movement of the steering wheel indicates that he wants to avoid an obstacle, the car will assess whether there is a risk of collision with anyone or anything nearby and, if there is no risk of collision, the system will help the driver manage this manoeuvre,” Petr explains. The system also makes sure that the manoeuvre is not too sloppy and that the driver does not end up off the road.
In this case, the car evaluates data from sensors and other systems, including the Lane Assist system. In Škoda cars, this uses a camera to detect not only white and yellow lines, but also roadsides with asphalt-gravel or asphalt-grass transitions, curbs, concrete barriers, bollards and so on. Lane assist works at speeds above 65 km/h. “For the system to be triggered, the camera only needs to see the lane boundary on one side, and it uses that boundary to guide the driver,” says Ondřej Smetana.
During the demonstration, a monitor showed how Lane Assist lets a car “see” lane boundaries
According to Ondřej, the system detects the distance between the car and the lane boundary, evaluates how fast the car is approaching the boundary and adjusts the steering accordingly. “The system is not active at lower speeds and it doesn’t work on sharp corners with lateral acceleration of 3 m/s or more. In addition, the system also detects the driver’s activity via the steering wheel, but the driver still has to drive,” Ondřej explains. On gentler curves, though, the system allows the driver to “cut” the curve, i.e. to get as close as possible to its inner edge. Similarly, the system does not intervene when the turn signals are used (unless a car is detected in the driver’s blind spot). “The driver can always override the assist system by exerting force, though,” Ondřej adds.