BMW is working to lessen the number of fatalities caused by drivers turning left at intersections (in left-hand drive countries, that is). When the "left hand drive assistant" detects that the driver intends to turn left, three laser scanners in the front end of the car kick in to map the area up to 100 meters (328 ft) ahead. If the system detects oncoming vehicles and the driver continues to move into the intersection, it will sound a warning and automatically activate the brakes to prevent a collision.

The left turn assistant, which is being tested on the BMW 5 Series test vehicle, recognizes when the vehicle is entering the left turn lane in two ways: through the use of the vehicle's navigation system, which can fix the car's location to within a meter (3.3 ft) at an intersection, and by detecting the turn-off lane markings and lane borders on the road through the use of a mono camera. Another test scenario being run by BMW sees the system being activated when the driver hits the vehicle's turn signal.

Once the system is activated, the three laser scanners in the vehicle's front end scan the area to detect oncoming cars, trucks and motorcycles. If any approaching vehicles are detected and the driver continues to move into the intersection the system will apply the brakes, sound a warning and display a warning in the instrument cluster and head-up display. To ensure the system doesn't slam on the brakes when the vehicle is traveling at high speeds, the system will only apply the brakes if the vehicle is moving at less than 10 km/h (6.2 mph).

To override the system's braking input, the driver need only tap the brake themselves and the brake is released. This allows the driver to continue driving if they are trying to pull the car over to the side of an intersection or clear the way for an emergency vehicle, for example.

BMW says the functionality of the left turn assistant can also be enhanced through the use of vehicle-to-vehicle communication systems, such as its WLAN car-to-x communication unit. These allow the vehicles to exchange information, including vehicle type, position, speed, current steering angle and whether the turn indicators are activated. Using such a system in conjunction with the left turn assistant results in an increase in range of the system to 250 meters (820 ft), as well as providing the ability to detect the presence of vehicles that may not be visible to the turning vehicle.

BMW will premiere the left turn assistant at the INTERSAFE 2 Final Event on May 17 and 18 at a closed-off intersection in Wolfsburg, Germany. While the system is designed for left-hand drive countries, we assume it could easily be modified to become a right turn assistant for right-hand drive countries.