Despite what you might be thinking, this story has nothing to do with BMW joining NASCAR. Instead, it’s the latest safety innovation by the Munich-based automaker, called Left Turn Assistant (LTA). Equipped in a 5 Series test vehicle it is designed to work at speeds of up to 6 mph, using three laser scanners in the front of the car map the area ahead by up to 100 meters.
These sensors will pick up cars, trucks, and motorcycles. If the sensors detect vehicles approaching from the opposite direction but the car continues to move into the intersection, the left turn assistant activates an automatic braking input in a low speed range up to 6 mph to prevent a collision. To further assist in executing the turn, a warning sound and relevant warning symbols in the instrument cluster and Head-Up Display advise the driver of the reason for the intervention. If the driver engages the brakes himself, the breaking input triggered by the left turn assistant is disengaged and the car is “released” again to continue normal driving. For maximum safety, the driver can always override the left turn assistant.
The BMW engages and recognizes the left turn lane on two levels. Firstly, the vehicle positioning function of the navigation system allows the location of the car to be fixed to within a meter at intersections. Secondly, the system uses a camera to register the turn-off lane markings and lane borders on the road. When fitted with a special WLAN car-to-x communication unit the LTA system’s range is increased to 250 meters and can detect other vehicles on the road using the system, even if they aren’t in view.