Safe driving

Safe driving

Most accidents begin long before the impact. For example, with poor visibility or unforeseeable hazards. This is why the Tourismo is equipped with a number of safety features that help master critical driving situations.

Starting with the ergonomic driver's workplace. The driver can comfortably reach all controls and has a perfect view of all the instruments. The wide-angle exterior mirrors guarantee more safety through better all-round vision.

While on the move electronic assistants support the driver. The anti-lock braking system (ABS) minimises the risk of the wheels locking when braking. The electronic-pneumatic brake control (EBS) significantly shortens the stopping distance, as the brakes are actuated faster and more precisely. The Acceleration Skid Control (ASR) system provides additional safety. It helps the driver to minimise the risk of the rear of the vehicle (rear-wheel drive) breaking out laterally when accelerating. ABS, EBS and ASR form the basis for further developed electronic safety systems such as the Electronic Stability Program (ESP®) or the Brake Assist System (BAS), with which the Tourismo is also equipped.

Independent of the function of the proximity control system (ART), Active Brake Assist 4 warns the driver of a collision with an obstacle and brakes the bus independently if necessary. The radar-controlled system continuously scans the traffic lane at a distance of up to 250 metres ahead of the bus.

As the first system of its type worldwide ABA 4 also reacts to pedestrians. Thus, beside vehicles moving ahead and stationary obstacles (e.g. a tailback) the system also detects pedestrians at a maximum range of 80 metres. If for example the distance from pedestrians reduces dangerously, the system first alerts the driver by visual and acoustic warning signals, simultaneously initiating partial braking to a standstill if the driver does not react. The resulting partial braking gives the driver the opportunity to avoid a collision through full braking or a steering manoeuvre. Additionally, he can warn endangered pedestrians by sounding the horn in good time.

The Adaptive Cruise Control feature (ACC) relieves the driver by maintaining a constant distance – defined by the driver – from the vehicle ahead, based on continuous measurements. This not only increases safety on country roads and motorways, but also convenience.

A radar system, which guarantees outstanding functionality even under poor weather conditions and in the dark, monitors a distance of up to 250 metres in front of the vehicle and to the full width of the road. If the distance from the vehicle driving ahead falls below a variably defined safety distance, ACC slows the bus down so that the safety zone is maintained. Many rear-impact collisions can therefore be avoided.

The centrepiece of the adaptive cruise control is a radar sensor at the front of the vehicle. This sensor uses three radar beams to scan the surroundings every 50 milliseconds ahead of the vehicle, thus monitoring all three lanes of a motorway, for example. In case the radar signals detect a moving vehicle ahead, they are reflected. A microcomputer then calculates the distance based on the reflected signal and the relative speed of the vehicles in relation to each other. This microcomputer is connected to the other safety systems of the vehicle via the CAN bus. If there is no vehicle ahead that is moving more slowly, the adaptive cruise control functions as a classical cruise control and it maintains the preset speed. Should the system, however, detect a vehicle ahead that is moving more slowly, it reduces the speed by a controlled operation of the engine and brake system. During this operation, no more than 20% of the maximum brake power will be applied. Only the driver can initiate stronger braking manoeuvres. The driver is alerted through visual and acoustic signals about the danger. If the distance to the vehicle ahead exceeds the minimum allowed distance again, the vehicle is accelerated until it reaches the preset speed once more.

The Front Collision Guard offers increased safety in the event of a head-on collision by means of a transverse profile behind which crash elements are located. Their absorber structure converts the impact energy into deformation energy. The transverse profile serves as a reliable underride guard. Since the driver’s work space is mounted on a massive frame component, it can be pushed backwards to maintain a protective space for the driver in the case of a frontal impact.

The patented technology includes a multi-part cross section as underride guard behind the bumper with the idea of protecting other road users, e.g. preventing a car from going under the bus. The front-end structure behind this cross section consists of crash elements that can selectively dissipate energy in the event of a collision. In addition, the driver's area, including steering, pedals and seat, is located on a massive frame section that is displaced rearward as a complete unit in the event of a serious head-on collision, thereby increasing the survival space by vital centimetres.

The FCG fulfils the requirements of the underride guard according to ECE-R 93, as well as legal norms for pendulum impact in buses. Moreover, the FCG already meets future statutory standards for pendulum impact tests on buses.

With the aid of a camera system behind the windshield, the Lane Departure Warning system detects when the vehicle unintentionally leaves a marked lane. As soon as the vehicle crosses the markings, the driver is warned by a clear vibration on the corresponding side of the driver's seat.

The LDWS is activated from a speed of 40 mph (60 km/h). The lane assist system is switched off when the turn signal is activated, for example when the driver initiates a deliberate lane change. The system can be deactivated in the ICUC menu, e.g. in a construction site.

A small camera behind the windshield uses boundary lines to record the road directly in front of the vehicle. If the vehicle is about to cross any of the markings without a turn signal being activated, the driver is alerted by a pulsation in the seat. The camera determines the instant of warning based on the width of the lane, the distance to the marking line, and the speed of approach to the marking. The LDWS becomes active above a speed of 40 mph (60 km/h); it is switched off by operating the turn signal, for example when initiating a deliberate change of lane.

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.

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).

By constantly comparing the data, the electronic braking assist system immediately detects if the speed at which the brake pedal is pressed suddenly exceeds the usual level, and in such situations automatically boosts the maximum braking power to within fractions of a second. This significantly shortens the stopping distance of the vehicle.

The control unit also takes into account the speed, as well as the load of the coach. BAS is a software function that builds on or uses the sensors and actuators of the EBS (electro-pneumatic braking system). Interventions by BAS can lead to the intervention of other stability control systems, e.g. ABS.

It happens at the critical moment: instead of braking fully and keeping the foot firmly on the pedal, the driver may brake quickly but not forcefully enough. In an emergency situation like this, the electronic brake assistant (BAS) kicks in automatically. It interprets the braking behavior and, in the event of an attempted emergency stop, builds up more braking force within fractions of a second than is actually required by the driver via the brake pedal. Thanks to BAS the braking and stopping distance are considerably reduced. With an average gain in reaction time of 0.4 seconds, the reduction in the braking distance of a coach at a presumed speed of 62.5 mph (100 km/h ) can be up to 33 feet (10 meters), a tremendous increase in safety in emergency situations

The continuous brake limiter (DBL) is a safety system that makes it impossible, for example, to decouple the drivetrain by depressing the clutch pedal when going downhill. DBL constantly monitors the maximum permissible speed of the vehicle. If a vehicle exceeds the maximum permitted speed, e.g. when driving downhill, DBL communicates with the other safety systems.

First, the fuel injection to the engine is interrupted. If this is not enough, the retarder (the wear-free continuous brake) is engaged. This increases safety, especially on sections with steep downhill gradients, and makes it impossible for accidental speeding to occur, as can easily happen in such situations.

The Electronic Stability Program (ESP®) significantly reduces the risk of the vehicle skidding and tipping over by selectively braking individual wheels or by braking the vehicle as a whole.

High-performance electronics monitor the signals from the ESP® sensors and constantly determine whether the steering commands of the driver match the actual movements of the vehicle. If the values deviate from one another, the system decreases the engine torque to restore stability to the vehicle. If this is not sufficient, it also brakes individual wheels or the entire vehicle. The driver’s request for deceleration is observed at all times.

The ESP contains the ASR safety system, which prevents excessive wheel slip during acceleration. The ESP brake interventions are also secondary to the ABS function, thereby avoiding blocked wheels. The ESP can be switched off and on again using a button on the instrument panel; the switch-off is indicated by a check lamp. (USA: only the ASR function contained in the ESP can be deactivated). ESP (USA: ASR) is automatically switched back on after the ignition is switched off/on.

Tyre Pressure Monitoring (TPM) displays the current pressure in the individual tyres and warns of deviations from the optimum pressure. This reduces tyre wear, has a positive effect on fuel consumption and prevents dangerous tyre damage.