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Distance Control, Basic Function - GF30.30-P-9903A

MODEL ALL (CAR) with CODE 239 (DISTRONIC PLUS) 

MODEL ALL (CAR) with CODE 23P (Driving Assistance package) 

MODEL ALL (CAR) with CODE P20 (Driving Assistance package Plus) 

Overview 

This document contains the following information:

General 

Distance control regulates the distance from a preceding vehicle as specified by the driver. To do this, the system uses the information from the radar sensor behind the radiator grille. Distance control can react to vehicles cutting in, driving ahead and stopping.

On approaching a preceding vehicle, the distance control system reduces the speed and brakes the vehicle, to a standstill if necessary. If the system recognizes that more extensive braking is necessary, the driver is warned visually and acoustically so that he can brake himself if necessary. If a collision is likely, Active Brake Assist intervenes to prevent an accident if possible. As soon as the traffic situation permits again, the vehicle accelerates up to the specified speed set in the speed control system.

If the driver actuates the accelerator pedal, distance control is switched to passive until the driver releases the accelerator pedal again.

If the fast lane is free and a lane change is indicated by flashing, the vehicle accelerates rapidly to the speed control system's specified speed.

The distance control system's driving style is influenced by the selected drive program. In the "Sport" drive program, for example, acceleration is more dynamic and sharp. In the "Comfort" drive program, distance control operates with greater emphasis on comfort.

Distance control is operated with the buttons on the steering wheel. The traffic situation is still evaluated even when distance control is switched off. As described above, warnings are then output or braking takes place in dangerous situations.

Function requirements 

Distance control 

Distance control is activated when the radar sensor detects a preceding vehicle and the driver sets a specified distance from it. Distance control evaluates the driving and traffic situation on the basis of the following parameters:

Starting off 

Distance control is activated by pressing the accelerator pedal or by selecting a set speed.

If a vehicle is located in the radar sensor's detection range, one's own vehicle follows it. Otherwise, the system activates speed control.

In stop-and-go traffic, the vehicle automatically drives on again within 3 s after stopping, and follows the vehicle in front. When the vehicle is stationary for longer, distance control switches off.

Vehicles with Driving Assistance Package and Active Parking Assist 

On roads with separate lanes (e.g. freeway), the vehicle automatically drives on again within 30 s after stopping, and follows the vehicle in front.

On vehicles with Active Parking Assist, the traffic area ahead of the vehicle is additionally monitored by the distance sensors.

Maintaining distance 

During vehicle operation, distance control can only be activated if a vehicle is located in the radar sensor detection range. This vehicle is then followed at the set distance.

The driver can continue to accelerate the vehicle himself. Distance control is interrupted as long as he actuates the accelerator pedal. A text message indicates this status.

If the distance control system requests higher acceleration than that specified by the driver, the driver's specification is overridden. Distance control switches to speed control under the following conditions:

Convoy driving (Western European countries with corresponding legislation) (vehicles with Driving Assistance Package) 

If a convoy forms as a result of the traffic situation on the left-hand lane, it may be overtaken on the right under the following prerequisites:

The preceding vehicle is followed at the set distance.

Pulling out/pulling in 

If the preceding vehicle pulls out during distance control and is ahead of a further vehicle, the distance is regulated to the new vehicle.

If a vehicle pulls into the safe distance from the preceding vehicle, the distance is regulated to this new vehicle. If a vehicle pulls onto the lane on which the own vehicle is driving during speed control, the distance is regulated to this vehicle.

If necessary, the distance control system brakes the own vehicle. This deceleration is limited to a maximum of 50% of the possible braking power. Distance control is thereby deactivated. This process is indicated to the driver by the output of warnings.

Distance control can then be activated again.

Driving through traffic circles, T-intersections, and freeway exits (vehicles with Driving Assistance Package, depending on country) 

Before entering traffic circles, T-intersections, and freeway exits, distance control brakes the vehicle.

If the preceding vehicle leaves the radar sensor detection range in one of the listed situations, the current speed is maintained:

If no preceding vehicle is then detected, the vehicle accelerates or decelerates to the set speed.

As road courses are subject to changes, regularly updating the digital map material is necessary.

Overtaking (vehicles with Driving Assistance Package with deactivated lane change assist) 

When overtaking at a speed over 70 km/h, distance control accelerates the vehicle automatically. The driver must introduce the overtaking process by flashing. System-related, automatic brake application is suspended (evasion). If required, the vehicle is accelerated more extensively.

The overtaking maneuver is broken off in the following situations:

Stop vehicle 

When distance control is active, the vehicle follows the preceding vehicle to a standstill. The vehicle is decelerated. The service brake secures the stationary vehicle against rolling away.

After a short time, the electric parking brake is activated (standstill control securing strategy). Securing the vehicle does not replace securing the vehicle when parking.

  Subsystems     
  Functional limitations of distance control, detailed information   GF30.30-P-0024-01A 
  Increase speed, basic function   GF30.30-P-1000A 
  Reduce speed, basic function   GF30.30-P-1001A 
  Environment monitoring, basic function Model all (CAR)
with code 235 (Active Parking Assist with PARKTRONIC)
with code 23P (Driving Assistance package) Model all (CAR)
with code 235 (Active Parking Assist with PARKTRONIC)
with code P20 (Driving Assistance package Plus)		 GF54.65-P-1000A
  Collision warning system, basic function   GF54.70-P-9900A
  Traffic area monitoring, basic function   GF54.71-P-1000A
  Additional basic functions     
  Brakes, basic function   GF42.00-P-9900A
  Control units     
  Intelligent driving control unit, basic function Model all (CAR)
with code 23P (Driving Assistance package)
Model all (CAR)
with code P20 (Driving Assistance package Plus)		 GF30.30-P-9890A 
  Distance control controller unit, basic function Model all (CAR)
with code 239 (DISTRONIC PLUS)		 GF30.30-P-9891A 
  Parking system control unit, basic function Model all (CAR)
with code 235 (Active Parking Assist with PARKTRONIC)
with code 23P (Driving Assistance package)
Model all (CAR)
with code 235 (Active Parking Assist with PARKTRONIC)
with code P20 (Driving Assistance package Plus)		 GF54.65-P-9890A
  Components     
  Intelligent driving radar sensor, basic function Model all (CAR)
with code 23P (Driving Assistance package)
Model all (CAR)
with code P20 (Driving Assistance package Plus)		 GF54.71-P-2005A
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