System Restrictions
The adaptive speed control system is only intended to provide enhanced speed control as described above in certain restricted conditions. The following points should be noted:
- Automatic braking is limited to approximately 30% of full pressure (0.3G deceleration) and is intended to provide a smooth, gradual deceleration in follow mode conditions. Harsh braking by the target vehicle or following the target vehicle down to very low speeds or to a halt will require the driver to intervene and override the brakes. A 'driver intervene' message will be displayed in the message center accompanied with an audible chime.
- While the radar sensor detects moving and stationary targets for assessment of the environment ahead, the system does not react to or provide any control in situations other than follow mode conditions. Stationary or slow moving vehicles (below 6 mph (10 km/h)), pedestrians, objects on the road and oncoming vehicles in the same lane are not recognized.
The following illustration shows circumstances where the adaptive speed control system may brake late or unexpectedly. The driver is required to intervene in these situations.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Driving on a different line to the vehicle in front. |
| 2 | Vehicles that merge into the same lane are only detected once they have moved fully into the lane. |
| 3 | On bends in the road there can be issues with detection of the vehicle in front when going into and coming out of a bend. |
In follow mode, some situations may cause target ambiguities for the detection system. These situations include:
- The nearby presence of a third vehicle when driving on a line slightly offset to the target vehicle.
- Vehicles edging into the lane ahead which are not detected by the system until they have moved into the radar beam.
On the approach to, or exit from a bend, a target vehicle may be lost or a new target acquired as vehicles ahead change their angular position with respect to the radar sensor. On a straight road, if the sensing vehicle is in follow mode below its selected set speed, losing the target vehicle will cause the sensing vehicle to accelerate to this set speed. This acceleration is undesirable either on, or entering a bend when the target is suddenly lost, and in this situation the system inhibits the resumption of the set speed.
The speed control system compares vehicle speed data from the ABS control module with the relative speed of an external object as detected by the radar sensor to ascertain whether the object is stationary or not.