The Electronic Stability Program (ESP®) is an active system for increasing driving safety and 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 critical, dynamic driving situations, for example if the bus approaches physical limits when cornering. At the same time, the engine output is reduced. A possible "breaking-out" of the bus is thus prevented by the finely metered braking within the limits of the physical possibilities.

Among other things, ESP® monitors the lateral acceleration of the bus. If, on long bends – such as motorway exits – or with rapid lane changes, the bus reaches a critical driving situation, the vehicle speed is automatically reduced so the bus returns to a situation of driving stability. The ESP® is comparable to that used in passenger cars, but is adapted for use in buses thanks to specific extended features.

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) breaking out laterally when accelerating. Especially for high-torque engines, ASR thus provides increased comfort and enhanced safety when pulling away – particularly on roads with varying grip.

How ABS works: there are sensors fitted on all four wheels which detect the rotational speed of each wheel and pass this information on to a central control unit. If the critical point of blocking the wheels is reached, the wheel is stopped at precisely that threshold by pressure variation. The brake pressure can be increased and decreased numerous times in the space of a second.

When braking, all the forces acting on the wheels and the rolling behaviour are continually monitored. The braking forces acting on the wheels are distributed in such a way that no wheel can lock, and the steerability of the vehicle is preserved as far as possible.

In December 1970, Mercedes-Benz presented the world's first electronically controlled ABS – a revolution in driving and road safety. Thanks to targeted electronic braking intervention, the wheels don't lock for long times. The risk of losing steering stability is minimised and, in the case of a full application of the brakes, the vehicle can be steered in the desired direction. ABS technology forms the basis for further developed electronic safety systems such as the electronic stability program (ESP®) or the brake assistance system (BAS).

The high traffic dynamics in city bus transport make great demands on the driver. The Sideguard Assist assistance system supports the driver primarily when turning towards the left in road traffic by making the driver aware of the presence of other road users and stationary obstacles and by warning if there is a danger of collision.

The system operates in multiple stages: in the first stage, it informs the driver, in the second stage it emits an additional warning. 

If a moving object is located in the side monitoring zone, the driver is informed visually. A triangular-shaped yellow LED lamp lights up on the A0 pillar on the co-driver's side. A warning symbol additionally appears on the central display. If the driver initiates or continues an action that could lead to a collision, an additional visual warning is given. The LED lamp flashes first in yellow, then in red. After this the highest level alarm follows: a red flashing lamp accompanied by vibration of the driver's seat.

In addition, Sideguard Assist can perform the task of a lane change assist function; it works with the same warning cascade. 

The Preventive Braking Assist function from Mercedes-Benz is the world's first active Brake Assist System for public city transport buses. This assistance system warns of a possible collision with stationary or moving objects. In case of an acute danger of collision automatically initiates a braking manoeuvre with partial braking. Warning cascade and brake application are precisely designed for use in urban traffic. 

In case of an imminent collision, the Preventive Brake Assist function warns the driver both visually, with a red triangle with a vehicle symbol lighting up in the central display, and acoustically. At the same time the system initiates a partial braking manoeuvre. This brake application is held until either the driver intervenes or the bus comes to a stop. 

The eCitaro also features the Acoustic Vehicle Alerting System, a sound generator which creates an artificial sound effect similar to a combustion engine, at speeds up to 30 km/h. The system increases people's awareness of the quiet, fully electric eCitaro and thus protects pedestrians and cyclists.

The cornering light function provides significantly improved safety for night-time driving when turning corners at poorly lit junctions, at roundabouts or when manoeuvring and reversing.

The cornering light function is activated automatically at speeds of up to approx. 40 km/h if the main headlamps are on, the turn signals are actuated or the steering wheel is turned. One of the two front fog lamps is switched on to illuminate the area to the side and front of the vehicle which is not lit by the main headlamps. The intelligent electronic system switches the dimmed cornering lights on or off. This gives the eye a chance to adjust to the changed light situation.

The video monitoring cameras installed can keep track of the events taking place on the bus. A video monitoring system can not only improve the sense of safety for the bus driver and passengers, it can also record troublemakers who commit acts of vandalism or violence.

The data is transmitted to the monitor in the bus driver's workstation. The bus driver can then better view and evaluate events occurring in the passenger compartment and, if needs be, react in the event of danger.

The vehicle is labelled with pictorgrams to inform passengers that the vehicle is video-monitored. Video monitoring enhances the subjective sense of safety for driver and passengers and thus the appeal of using public transportation. The video monitoring system is an optional extra.

More information on the video monitoring function and data storage is available from our bus sales consultant.