Safe driving
CapaCity & CapaCity L

Safe driving

Especially in urban traffic, hazards are sometimes unforeseeable. All the more important, then, that measures be taken to prevent accidents. Mercedes-Benz has equipped the CapaCity bus with a number of safety features that help master critical driving situations.

The CapaCity and the CapaCity L support the driver with numerous assistance systems. The Acceleration Skid Control feature (ASR) prevents the drive wheels from spinning. The Electro-pneumatic Brake System (EBS) ensures that the stopping distance is significantly reduced, since the brakes are controlled more quickly and more precisely. ABS and the Sideguard Assist and Preventive Brake Assist also ensure predictive braking and manoeuvring.

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.

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.

With the Preventive Brake Assist feature, Mercedes-Benz is offering the first Active Brake Assist for city line buses worldwide. The assistance system warns of a potential collision with moving pedestrians as well as stationary or moving objects and automatically initiates a braking manoeuvre with partial braking in the event of an acute collision hazard.

Warning cascade and braking intervention are designed for use in city traffic. In the event of an imminent collision with pedestrians and with moving or stationary objects, the Preventive Brake Assist warns the driver visually by a red illuminated triangle with a vehicle symbol in the central display as well as acoustically, while initiating partial braking. This is held until either the driver intervenes or the bus comes to a stop.

The platform for the Preventive Brake Assist is a new generation of radar technology: the radar system continuously scans an area of up to 250 metres in the lane in front of the bus and works reliably even at night and adverse weather conditions.

Sideguard Assist is a safety assistance system that supports the driver in critical cornering situations where visibility may be limited. When turning or changing lanes, the system is designed to help avoid critical situations, within its limitations, or reduce the consequences of accidents.

The function of the system and the warning concept were established based on the analysis of accidents while cornering that involved pedestrians and cyclists. In the majority of accident scenarios, the cause is due to the movement of both parties involved (vehicle and pedestrian/cyclist). In these cases, the system provides early information (yellow display) about moving persons or vehicles in a zone alongside and over the entire length of the vehicle and warns the driver as soon as the situation becomes critical (red).

Should the vehicle enter into an unstable driving condition – say, on a slippery road – the dampening of the articulation joint is corrected fast and as needed. This way the articulated bus is very rapidly stabilised – within the bounds of physical possibilities – in order to prevent the rear vehicle body from oscillating or even swerving out of control, thus avoiding the dreaded jackknifing effect. The new Articulated Turntable Controller (ATC) is the only regulation system of its kind to act in a manner akin to the Electronic Stability Program (ESP®).

Citaro G, jackknifing protection system winter testing in 2014 in Rovaniemi

The CapaCity is the best example of how vehicle size need not conflict with manoeuvrability. Both models, the CapaCity and the even longer CapaCity L, are easy to manoeuvre. Of course, Mercedes-Benz includes safety as a standard feature.

The dynamic articulation angle control system, the Articulation Turntable Controller (ATC), affords optimal steering ability, high stability and agility. With the aid of the ATC, the articulated bus is then very quickly stabilised within the limits of physical possibility and pivoting or even breaking out of the rear section avoided. In this way, the ATC articulation angle control system comes to approximate the effect of electronic stability control (ESP®). The result is an even higher safety level for articulated buses. The steering ability of the CapaCity thus comes close to that of a solo vehicle.

Jackknifing protection system in the Mercedes-Benz Citaro G / CapaCity L articulated buses

Jackknifing protection system, maximum turn 54°

 

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.

A precondition and challenge for safely driving a large capacity bus is a perfect overview of the surroundings, especially in the vicinity of the rear section. The CapaCity already simplifies the view by virtue of its single-pivot construction. In addition, several external cameras provide an overview of what's happening around the rear section. Manoeuvring and backing up are as easy as with any other single-pivot bus.

The CapaCity has video cameras mounted at the rear on the left and right. The driver can accordingly monitor the pivoting area when leaving a bus stop and in the middle of traffic. Two other side-mounted cameras positioned directly behind the articulation joint allow monitoring of the rear section.

For additional safety during manoeuvring, Mercedes-Benz also offers reversing cameras as a supplement to the external rear cameras. A continuous warning tone sounds while backing up. Manoeuvring as well as backing up can therefore be comfortably mastered.

A concentrated driver significantly contributes to safety on the road. Electronic aids support the driver in the best possible way. On the CapaCity all doors come with a reversing device as well as horizontal door area monitoring. The third and fourth doors are fully automatic. And the double-wing doors one through four allow a fast passenger throughflow. For additional relief of the driver, the interior spaces of these doors can also be video-monitored as an optional extra.

External rear camera for monitoring the pivoting area at the bus stop and in road traffic.

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 special equipment.

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

The low beam and high beam benefit from the outstanding luminous efficacy of the integral LED headlights, which also use significantly less energy than standard lights. They provide broad and precise illumination of the road. Another safety benefit is the temperature of the light, which is similar to that of daylight and makes the eyes tire less quickly. The LED lights assure a long service life and low degradation (decrease in luminosity).

The light cone of the LED headlights is precisely defined. More brightness and longer range provide additional safety. LED lamps are about two to three times more efficient than conventional incandescent lamps.

The headlights reach their full luminous intensity immediately after being switched on and provide wide-ranging and precise illumination of the road. They have a soft cut-off line and a subjectively larger reach. And LED headlights increase economic efficiency through their low power consumption and long service life. They have low degradation, i.e. the light output remains largely consistant over their service life.