Driving assistance systems: Superior support in tailbacks

Jun 24, 2019
Stuttgart/Salt Lake City

The Mercedes-Benz GLS uses the latest generation of Mercedes-Benz driving assistance systems to provide cooperative driver support. The level of active safety has not only been improved further compared to the preceding model.

Everyone is familiar with this tricky situation on motorways: on rounding a bend, the end of a traffic tailback suddenly appears. This is where the new GLS supports its driver with the Driving Assistance Package, as tailback management on motorways now already begins in advance of a tailback, including assistance in stop-and-go traffic and after the tailback has dissolved.

When Active Distance Assist DISTRONIC with route-based speed adaptation is active, the new GLS is able to respond to Live Traffic info - ideally before the driver or the radar and camera sensors can detect the hold-up or hazard. When a traffic tailback is detected, the speed is reduced to approx. 100 km/h as a precaution unless the driver specifically decides otherwise.

New feature of Driving Assistance package Plus: When actually driving in a tailback, Active Stop-and-Go Assist can markedly reduce the driver's workload: where there are lane markings, the system is substantially able to perform the tasks of keeping in lane and maintaining the safety distance with a high level of availability at speeds up to around 60 km/h. The vehicle can move off again automatically up to one minute after coming to a stop.

Once the tailback clears, the GLS accelerates back up to the speed specified in Active Distance Assist DISTRONIC with route-based speed adaptation. If the driver has not set a specific speed, in Germany that speed is the recommended motorway speed of 130 km/h. Where traffic signs specify a different speed, Active Speed Limit Assist automatically selects the signposted speed limit.

To recognise tailbacks, Active Stop-and-Go Assist evaluates the road category, speed and distances from vehicles travelling ahead and in adjacent lanes. In addition to the stereo multi-purpose camera (SMPC) and long-range radar, it uses the front multi-mode corner radar sensors to recognise vehicles that are cutting in. If Active Steering Assist and Active Distance Assist are activated, Active Stop-and-Go Assist is switched on automatically when a motorway tailback is recognised. This is indicated by "Stop-and-Go Assist active" in the instrument cluster. As soon as Stop-and-Go Assist is active and the vehicle is moving in a tailback, a tailback symbol is added to the "green steering wheel" symbol of Active Steering Assist in the instrument cluster.

Active Steering Assist assists in forming an emergency lane

A new feature of Active Steering Assist is that it can support the driver with the emergency lane function on multi-lane roads. On motorways, at speeds under 60 km/h the vehicle refers to detected lane markings and applies swarm intelligence to take its bearings from vehicles in the surrounding area. If none are detected, the GLS takes its bearings from the vehicle ahead, as previously.

Always ready to help: numerous other assistants are available

It is not only by giving driver support in tailbacks that the new GLS further expands Mercedes-Benz Intelligent Drive and takes another major step towards autonomous driving. Active Distance Assist DISTRONIC and Active Steering Assist now provide even more comfortable support for the driver in keeping a safe distance and steering. With Active Speed Limit Assist, identified speed restrictions are adopted automatically in anticipatory mode. Active Lane Change Assist, Active Emergency Stop Assist and Evasive Steering Assist are also available.

A totally new feature of Active Brake Assist in the Driving Assistance Package is the turning-off function, which comes into play when the driver intends to turn off across the oncoming lane: if there is a risk of collision with oncoming traffic when starting off, the GLS can brake autonomously. Braking intervention takes place when the driver activates the turn signal indicator signalling an intention to turn off, and the vehicle can be braked to a standstill before passing over the lane marking. If not, no braking takes place, so as to enable the GLS to leave the opposite lane swiftly. Oncoming vehicles are detected via an intelligent fusion of radar and camera signals.

Other functions of Active Brake Assist include driver support to avoid impending collisions with stationary vehicles, vehicles ahead and crossing vehicles or pedestrians. 

This takes the form of

  • a distance warning from a warning lamp in the instrument cluster if the distance from a vehicle in front is insufficient,
  • an additional acoustic warning if the danger of a collision is identified,
  • braking assistance as appropriate to the given situation, should the driver fail to apply the brakes sufficiently firmly,
  • autonomous emergency braking to avoid a collision with moving, stationary or crossing vehicles ahead if the driver fails to respond,
  • autonomous emergency braking also for stationary or crossing pedestrians/cyclists.

The new GLS is additionally equipped with Active Blind Spot Assist including exit warning. This can provide the driver with intuitive warnings of vehicles, including bicycles, in the danger zone alongside their own vehicle. It can also apply one-sided braking to prevent impending side-on collisions or reduce the severity of such a collision. When the vehicle is at a standstill it can also signal to the driver with a visual warning in the exterior mirror before they climb out that a vehicle is driving past in the critical area. If the door handle is pressed at this moment, an audible warning will additionally sound, the ambient door lighting will flash in red and a message will appear in the instrument cluster. The function is also available when the vehicle is stationary and up to three minutes after the ignition has been switched off. Active Lane Change Assist: When the driver wishes to change lanes on multi-lane roads (recognised by the navigation system) at speeds from 80 to 180 km/h, it is sufficient to nudge the indicator stalk in order to activate support. Within the next ten seconds, the sensor system checks together with the driver whether the next lane is clear in front of, alongside and behind the vehicle, also taking into account the speed of any other vehicles. If there is no other vehicle within the relevant safety zone, the driver is supported in changing lane. The initiated lane change is indicated in the instrument cluster and in the head-up display. The system is available in certain countries, depending on the eligibility for certification.

Active Emergency Stop Assist: Active Emergency Stop Assist brakes the vehicle to a standstill in its lane if it detects that the driver is no longer actively driving the vehicle while it is on the move with Active Steering Assist switched on. If there is no steering wheel movement over a longer period when Active Steering Assist is active, the system gives the driver a visual and audible prompt to place his/her hands on the wheel. If the driver fails to respond after repeated visual and acoustic warnings by moving the steering wheel, accelerating, braking or operating the touch controls or other buttons on the steering wheel, the car is slowed down in the identified lane until it comes to a standstill. At speeds below approx. 60 km/h the traffic behind is warned by means of hazard warning lights. When the vehicle comes to a standstill, the parking brake is engaged automatically and the Mercedes-Benz emergency call system is activated. The vehicle is also unlocked, to allow first responders access to the interior. The functions are aborted as soon as the driver takes control of the vehicle again.

Evasive Steering Assist: Within a speed range from 20 to 70 km/h, Evasive Steering Assist can help the driver to avoid a pedestrian detected by the assistance system using the radar sensors and stereo multi-purpose camera. If the driver initiates an evasive manoeuvre by turning the steering wheel, the system provides assistance by adding precisely calculated steering torque to support the movement of the steering wheel. This torque helps the driver to avoid the pedestrian in a controlled manner and then makes it easier to straighten the vehicle up again so that it can drive past safely. While the philosophy behind Evasive Steering Assist is to provide the driver with significant assistance, the initiative to take evasive action must come from the driver. This is because if evasive action were automatic, a previously inattentive driver might be so surprised by the spontaneous movement of the steering wheel that they might react incorrectly and, for example, attempt intuitively to steer in the opposite direction.

Traffic Sign Assist: Image recognition and information from the digital road map in the navigation system allow determining the speed limit, no-overtaking zones and pedestrian crossings for the current route section and displaying them in the instrument cluster. Additional restrictions such as speed limits in wet conditions (warning when the windscreen wipers are switched on) or speed limits for trucks only are also taken into account or ignored as appropriate in the individual case concerned. The vehicle speed is compared with the speed limit. If set to do so by the driver, a visual/visual-audible warning is given if the speed limit is exceeded. No-entry signs are also recognised and the driver is prompted to check the vehicle's direction of travel. A warning additionally appears in the instrument cluster and on the head-up display if pedestrians are detected in the area of a zebra crossing. Traffic Sign Assist is also separately available outside the assistance package.

Active Speed Limit Assist: In conjunction with MBUX and the Driving Assistance Package, Active Speed Limit Assist, a selectable sub-function of Traffic Sign Assist, is also able to recognise sign gantries and road works signs captured by camera. Known limits, such as 50 km/h in built-up areas or 100 km/h on country roads, are also adopted from the navigation system. Active Distance Assist DISTRONIC adapts the vehicle's speed to the recognised speed limits automatically (in combination with navigation and traffic sign recognition). In this case, the speed can be adapted in anticipatory fashion based on map data when entering towns. On roads without speed limits, such as stretches on German motorways, the recommended speed – in this case 130 km/h - is adopted as the set speed. This speed can be adjusted by the driver. The desired maximum speed is always adopted in the course of the journey when the speed limit is cancelled. It remains preset until the vehicle leaves the motorway or until the engine is switched off.

PRE-SAFE® PLUS: When there is a sustained risk of collision, this system can warn any following vehicles approaching too fast by quickly flashing the rear hazard warning lamps, trigger the belt tensioners and lock the stationary vehicle's brakes in anticipation of a rear-end collision in order to minimise the risk of injury by reducing the forward jolt resulting from the impact.

Easier parking and manoeuvring: further assistance systems on request

Active Parking Assist with PARKTRONIC assists the driver when searching for a parking space and when entering or leaving parallel or end-on parking spaces. In the case of end-on parking spaces it is active in both forward and reverse direction. It manoeuvres the vehicle into the selected parking space and back out again. In the process acceleration, braking and gear-changing is automatic. In combination with Blind Spot Assist, the system can warn the driver of cross-traffic when reversing out of end-on parking spaces, and also initiate automatic braking if necessary. Parking Assist PARKTRONIC gives a visual and acoustic warning of recognised obstacles with the help of six ultrasonic sensors in each bumper. These can be in front of, to the side or behind the vehicle, and are detected at speeds up to approx. 10 km/h.

The Parking package with reversing camera combines Active Parking Assist with a reversing camera in the boot lid. Its image is shown with superimposed guide lines in the media display. The GLS is equipped with a reversing camera as standard.

If the Parking package with 360° camera is specified, an all-round view is provided by the 360° camera with four networked close-range cameras in the radiator grille, boot lid handle and exterior mirror housings. The information is clearly presented in selectable views in the media display.

ATTENTION ASSIST, Active Lane Keeping Assist, Speed Limit Assist and Active Brake Assist are on board as standard, offering a comprehensive range of safety functions, such as:

  • a distance warning from a warning lamp in the instrument cluster, if the distance from a vehicle in front is inadequate,
  • an additional acoustic warning if the danger of collision is identified,
  • braking assistance appropriate to the given situation as soon as the driver applies the brakes,
  • autonomous emergency braking for moving, stationary or crossing vehicles ahead if the driver fails to respond, 
  • autonomous emergency braking also for stationary or crossing pedestrians/cyclists.