Safe driving

Safe driving

For years, Mercedes-Benz has pursued its vision of accident-free driving. The integral safety concept covers all phases of automotive safety — safety when driving and in dangerous situations, protection in the event of an accident and minimising the impact of an accident. Safety is also integrated into the eCitaro city buses as standard. The body itself protects the passengers in the event of side impact. In the event of a rear-end collision, the reinforced front end minimises the impact of an accident while protecting the driver.

The modern MirrorCam system provides a clear and full view of the road traffic. Equipped with high-resolution cameras, the driving safety is improved and the risk of accidents is minimised. The extended field of vision enables the driver to see pedestrians, cyclists and other road users in the surrounding area. This eliminates the blind spot when turning right.

Depending on the vehicle, the images are displayed on 7" and 15" monitors. The two high-resolution displays show the different fields of vision. The photodiodes integrated in the monitors detect the incident light and adjust the brightness of the respective monitor individually. To make it easier for the driver to evaluate the images, the 15" variants have three different guide lines. Together with the permanently calibrated vehicle end line, the distance line assists the driver in assessing approaching objects. The Overtaking Assist overlay is activated from a speed of 10 km/h with flashing, in order to safely assist overtaking or turning. In addition, the display for Blind Spot Assist is installed in the monitor.

The high beam assistant automatically switches the high beam on or off depending on traffic, so that optimum illumination of the road is always ensured. In this way, it contributes to greater safety through improved lighting conditions and optimized illumination, and increases driving comfort and safety.

The function can be activated or deactivated. It is active from a speed of approximately 20 mph (35 km/h) and is automatically deactivated below a speed of approximately 15 mph (27 km/h). The function adapts to the illumination/brightness of the surroundings (no automatic switching on if there is sufficient street lighting).

The innovative Traffic Sign Assist offers maximum safety and comfort on the road. Thanks to GPS and camera support, the vehicle speed is constantly compared with the current traffic regulations.

The system is designed to provide dedicated and appropriate feedback if the permitted speed is exceeded. Thanks to the state-of-the-art instrument cluster, the driver receives both visual and audible signals that immediately draw attention to the speed.

Traffic Sign Assist (TSA). eCitaro

The Electronic Stability Program (ESP®) is an active system for increasing driving safety and driving stability. It makes a noticeable contribution to reducing the risk of skidding during cornering or evasive manoeuvres. This is achieved by specifically controlling the braking forces on each individual wheel in situations where the driving dynamics are critical, for example, if the bus is driven at the limit when cornering. At the same time the engine output is reduced. A possible "breaking-loose" of the bus is thereby prevented by the finely metered braking - within the limits of the physical possibilities. ESP® monitors, among other things, the lateral acceleration of the bus. If, on long bends – such as motorway exits – or during rapid lane changes, the bus reaches a critical driving situation, the vehicle speed is automatically reduced until driving stability is achieved again.

ASR prevents the drive wheels from spinning in two ways. On the one hand, ASR minimises wheel spinning through a measured braking intervention. On the other hand, the torque of the engine is regulated via the "electronic accelerator pedal".

Even at full throttle, the engine only provides as much power in critical situations as the drive wheels can transmit – a major advantage for controlled pulling away and driving stability. When starting off, the torques applied and the wheel speeds of the drive wheels are monitored. In this process, torque distribution is controlled in such a way that spinning is prevented. This ensures that optimum power flow is always guaranteed.

ASR helps the driver to minimise the risk of the drive wheels spinning and consequently of the rear of the vehicle (rear-wheel drive) drifting out sideways when accelerating. Especially for high-torque engines, ASR thus provides increased comfort and enhanced safety when pulling away – particularly on roads with varying grip.

The Anti-lock Braking System (ABS) supports driving stability during critical braking operations and ensures that the vehicle remains steerable. The braking forces acting on the individual wheels are distributed by the ABS so that even in an emergency braking situation no wheel is blocked for any length of time, and the steerability of the bus is largely maintained.

The control unit of the brake electronics records the current wheel speed via the pole wheels and wheel sensors. When braking, the system controls the brake pressure at the individual wheel brake cylinders via the control valves. During emergency braking and braking with locking wheels, the system opens and closes the control valves of the wheel brake cylinders fully automatically at very short intervals, thus preventing locking and keeping the vehicle steerable.

During emergency braking and braking with locking wheels, the system opens and closes the control valves of the wheel brake cylinders fully automatically at very short intervals, thus preventing locking and keeping the vehicle steerable.

Sideguard Assist 2 is a safety assistance system that supports the driver in critical situations when turning right or turning left when visibility is possibly restricted. The system is designed to help detect moving obstacles within the system limits, and warns the driver so as to avoid critical situations or reduce the consequences of accidents when turning off or changing lanes.

The side areas of the vehicle are constantly monitored. As a result, vehicles, pedestrians or cyclists who may be in the blind spot are detected on both the front passenger side and the driver’s side. The radar system precisely detects the movements and warns the driver of possible collisions. The intuitive user interface and clear warnings allow the driver to drive safely and relaxed.

Sideguard Assist 2. eCitaro

With Preventive Brake Assist 2, Daimler Buses offers the second generation of Active Brake Assist. The system warns of collisions with moving pedestrians and cyclists as well as stationary and moving objects. In the event of a serious risk of collision, the driver is alerted by a visual and acoustic warning and partial braking is initiated automatically.

Warning cascade and braking intervention are specifically designed for use in urban traffic. In the event of an impending collision with pedestrians or cyclists as well as with moving or stationary objects, Preventive Brake Assist 2 issues a warning. The driver is warned both visually by a flashing red triangle in the central display and acoustically, and simultaneously initiates partial braking. This braking intervention is maintained either until the driver intervenes, the situation is no longer critical, or the bus comes to a stop.

Thanks to the interaction of front radar, short-range radar and the front camera, the area up to 250 metres in front of the bus is constantly scanned. This assistance is ensured up to a speed of 60 km/h. In snow, rain, fog, heavy spray, glare/dazzling conditions, direct sunlight or constantly changing light conditions, the system range and detection of vehicles and people may be impaired.

The Acoustic Vehicle Alerting System (AVAS) is a sound generator that generates a noise similar to that of a combustion engine in a speed range of up to 18.6 mph when driving forwards and up to 3.7 mph when reversing. A pleasant sound alerts those in the vicinity of the fully electric bus.

The system increases the volume up to a speed of 20 km/h, and from this speed it reduces the volume again up to 30 km/h. In this way, it communicates the speed and any acceleration. At speeds above approx. 15 km/h, the rolling of the tyres makes a louder sound than the system itself. The system does not generate any noise emissions when the vehicle is stationary and cannot be switched off by the driver.

The sound generator is mounted behind the front panel on the left-hand side of the vehicle. With the AVAS, the sound level of the electric bus is approx. 5–6 dB above the required minimum noise according to UNECE-R 138.01.

The cornering light function provides even more safety through better visibility conditions at night-time when cornering at intersections and roundabouts and when manoeuvring in forward driving and backing up.

The cornering light function is activated automatically at speeds of up to approx. 35 km/h if the main headlamps are on, the turn indicator is actuated or the steering wheel is turned. One of the two front fog lamps then cuts in to illuminate an area on the side in front of the vehicle that is not being illuminated by the main headlamps.

The intelligent electronic system switches the cornering lights on or off progressively in the same way as a dimmer switch. This gives the driver's eyes a chance to adapt to the change in light.

Both agile and robust. The Articulation Turntable Controller (ATC) developed by Mercedes-Benz is a sophisticated anti-jackknife system for articulated buses. This swivel joint and its control system form one of the core components of the vehicle.

Articulated bus joints usually have high levels of basic damping. This invokes a strong inclination for the driver to understeer when cornering and increases tyre wear on the front axle. This is where the driving dynamics control system Articulation Turntable Controller (ATC) comes in.

The dynamic ATC regulates the hydraulic dampening of the articulation joint quickly and above all when and where it is needed, depending on the steering angle, the angle of the articulation joint, the speed and the load, among other factors. To this end the ATC falls back on the data from the CAN bus.

The otherwise usual high damping of the joint leads to a strong tendency to understeer in curves and increased tire wear on the front axle, this vehicle’s joint runs freely under normal running conditions and is attenuated only by the friction of the elements.

The wireless tyre pressure monitoring with indication in the multifunctional display is an electronic safety system that permanently monitors the air pressure of all tyres. Tyre pressure losses are displayed within the system limits.

The right tyre pressure contributes to driving safety and significantly reduced fuel consumption. Even a tyre pressure set 0.5 bar too low can increase fuel consumption by up to 5%. The wheel electronics are positioned on the valve on the inside of the rim. The sensors record the data relevant to the tyre pressure and transmit it to the display instrument.

The tyre pressure is recorded both when the vehicle is stationary and when it is moving. Caution! A sudden loss of pressure, for example due to the penetration of a foreign body, is not immediately indicated by the tyre pressure monitoring system. Damage to the tyres that does not lead to acute pressure loss is also not detected by the monitoring system. Here, visual inspection by the driver is and remains essential.

The 360° camera system consists of four cameras that capture the immediate vehicle environment and generate an indirect all-round view. The associated 10" screen is located on the A-pillar above the cockpit. This system allows pedestrians, cyclists and obstacles to be seen even in areas that are otherwise not visible to the driver. In this way, the system increases road safety, as collision hazards can be detected and, at best, prevented.

The views from the 360° camera are available up to a speed of approx. 20 mph (30 km/h) when driving forwards and always when reversing. Note: Risk of accidents due to objects protruding into the traffic area above the cameras, e.g. protruding roofs, exterior mirrors of your own and other buses, etc. The cameras cannot detect these objects. Particularly in the 360° view, the impression of a free environment can be created even though objects above the mounted cameras protrude into the turning space.

Installed video monitoring cameras can monitor events in the bus. A video monitoring system can not only improve the perceived safety for the bus driver and passengers, it can also deter hooligans committing acts of vandalism in the vehicle and record acts of violence.

The data is transmitted to the monitor in the bus driver's workstation. The bus driver can then better discern and assess certain situations and events occurring in the passenger compartment and if necessary react to any threat. The vehicle is labelled with pictograms to inform passengers that the vehicle is video-monitored. Together with the video monitoring, they increase the perceived safety for your driver and the passengers and thereby enhance the attractiveness of public transport. The video monitoring system is optional equipment.

For more information on the functioning of the video monitoring and data storage, contact our bus sales advisor.

* Optional equipment