How It Works

ACC is an autonomous system that automatically regulates the motorcycle speed to maintain a specific distance to the vehicle in front. The system adapts to keep the distance defined by the rider, who can choose between 3 tailing proximity options (short, medium and long). Both the riding speed as well as the distance to the vehicle in front can be set conveniently using a button all while the individual settings are displayed on the TFT instrument cluster. Tailing distance is determined by a radar sensor installed in the front of the motorcycle.

The rider can also select the aggressiveness of the system. The new BMW Motorrad ACC has two selectable control characteristics: comfortable or dynamic, in which the acceleration and deceleration behavior is changed accordingly. The distance control can also be deactivated in order to be able to use the Dynamic Cruise Control (DCC). When cornering, the speed is automatically reduced by the ACC if required and a comfortable lean angle is aimed at. With an increasing lean angle, however, the braking and acceleration dynamics are limited in order to maintain a stable rideability and not to unsettle the rider by abrupt braking or acceleration. 

High Degree of Control

The ACC functionality is distributed across several control units. Objects driving in front are detected by the radar sensor at the front of the motorcycle. At the same time, the radar sensor uses the yaw rate and the vehicle speed to determine the motorcycle path. If an object is detected in the bike’s path, the system responds and the speed is adjusted to ensure the set distance to the object.

This distance controller in the radar sensor sends a target acceleration which is received by the ABS and taken into account in the cruise control. The ABS determines the necessary acceleration and requests a drive torque from the engine and, if required, a braking torque from the brake system to accelerate or decelerate the motorcycle.

According to BMW Motorrad, ACC is a rider assistance system that leaves the responsibility with the rider and allows him to intervene at all times. That is also because the new ACC only responds to moving vehicles. Stationary vehicles – like at the end of a traffic jam or at traffic lights – are not considered. In such cases, the rider has to do the braking.

Two Warning Levels

The first warning level or takeover request 1 (TOR1) is displayed when ACC control is disabled by the system and a vehicle in front is detected. The rider must then intervene and ensure the distance to the vehicle in front. TOR1 is activated, for example, if the speed drops below the minimum of 18 km/h in ACC mode and the control is deactivated to avoid stalling the engine.

The second warning level (TOR2) is displayed if the system detects a dangerous situation in which the distance control cannot ensure the required minimum distance even at maximum permitted brake actuation (ACC must not activate emergency braking). Any abrupt possible braking
maneuver of the vehicle in front is taken into account. ACC continues to carry out any necessary braking, but the rider has to be ready to brake and if necessary must brake to avoid a collision.

BMW ACC Arrival

It remains to be seen if BMW will beat its competitors and be the first motorcycle brand to bring the technology to market. So far, they have not specified when exactly they will debut the system on their motorcycles and what specific models will be equipped with it, but we can expect it will be a priority for BMW to equip its top-tier R1250GS range with this latest tech. We’ll share more details about ACC’s release as soon as we learn more.