Mercedes-Benz C-Class Manuals

Mercedes-Benz C-Class (W205) 2015 - 2021 Owners Manual: Function of route-based speed adaptation

The following function is country-dependent and only available in conjunction with the Driving Assistance Package.

When Distance Assist DISTRONIC is active, the function adjusts the speed depending on the route events ahead. Depending on the drive program selected, the vehicle negotiates the route event ahead in a fuel-saving, comfortable or dynamic manner. When the route event has been passed, the vehicle accelerates again to the stored speed. The set distance to the vehicle in front, vehicles detected ahead and speed restrictions ahead are taken into account.

Route-based speed adjustment can by configured in the multimedia system.

Route events ahead are:

  • Bends
  • T-intersections, traffic circles and toll stations
  • Turns and exits
  • Traffic jams ahead (only with Live Traffic

When the toll station is reached, Active Distance Assist DISTRONIC adopts the speed as the stored speed.

Also, the speed is reduced if the turn signal to change lanes is switched on and one of the following situations is detected:

  • Turning off at intersections
  • Driving on slowing-down lanes
  • Driving on lanes adjacent to slowing-down lanes

The driver is responsible for choosing the right speed and observing other road users. This applies in particular to intersections, traffic circles and traffic lights, as route-based speed adaptation does not brake the vehicle to a standstill.

When route guidance is active, the first speed adjustment is carried out automatically. If the turn signal indicator is switched on, the selected route is confirmed and further speed adjustment is activated.

Speed adjustment is canceled in the following cases:

  • If the turn signal indicator is switched off before the route event.
  • If the driver depresses the accelerator or brake pedal during the process.

System limitations

Route-based speed adaptation does not take right of way regulations into account. The driver is responsible for complying with road traffic regulations and driving at a suitable speed.

In difficult conditions (e.g. unclear roads, narrow lanes, wet road surfaces, snow or ice) or when driving with a trailer, the speed adjustment made by the system may not always be suitable. In these situations the driver must intervene accordingly.

WARNING Risk of accident in spite of route-based speed adjustment
Route-based speed adjustment might malfunction or be temporarily unavailable in the following situations:
  • If map data is not up to date or available
  • If you do not follow the selected route guidance
  • If the set route is re-planned
  • In road construction areas
  • When towing a trailer
  • In bad weather or road conditions
  • If the accelerator pedal is depressed
  • Adjust the speed to the traffic situation.

Setting route-based speed adjustment


  • Active Distance Assist DISTRONIC is activated.

Multimedia system:

Vehicle → Assistance → Speed Adjustment

  • Activate or deactivate the function.
    Function of Active Speed Limit Assist

    Active Steering Assist

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