Avoiding dangers, saving lives: the new unparalleled assistance systems in buses from Mercedes-Benz and Setra

• Ten years of Active Brake Assist in touring coaches
• Premiere: Active Brake Assist 4, the first ever active brake assist system with pedestrian detection for touring coaches – as standard
• Premiere: Preventive Brake Assist, the first ever active brake assist system for city buses
• Premiere: Sideguard Assist, the first ever turning assistant for city buses and touring coaches

Mercedes‑Benz and Setra traditionally are the safety brands among buses and coaches. Nearly all safety and assistance systems celebrated their premiere in buses and coaches from Mercedes‑Benz and Setra. One outstanding example in this regard is Active Brake Assist, the first generation of which was presented exactly ten years ago. The next major steps are following now: Active Brake Assist 4 for touring coaches is the first ever brake assist system that also brakes for pedestrians. It will become standard equipment on all touring coaches from Mercedes‑Benz and Setra in 2019. Preventive Brake Assist is the first active brake assist system ever for city buses. Finally, Sideguard Assist is the first assistance system to warn of pedestrians, cyclists and stationary obstacles when turning. All three assistance unburden the driver in his work and protect more vulnerable road users. All three can save lives.

The integral safety concept

For the buses and coaches from Mercedes-Benz and Setra, safety does not consist of individual measures, but is rather the result of a comprehensive integral safety concept. The claim that stems from this approach is emphatic: These premium brands meet the highest safety expectations and drive development work forward in all areas. The integral safety concept comprises several components. It centres on numerous innovative vehicle and application-specific safety systems with the aim of continuously improving active and passive safety. This is accompanied by several additional measures such as driver training. The aim is for drivers to identify and avoid hazards in a timely way. They should also respond correctly in an accident. Information to familiarise passengers with the safety equipment on-board – starting with fastening their seat belts – forms part of the concept. It also goes well beyond this, however, even including conscientious vehicle maintenance and the use of tested genuine parts in vehicle servicing. The aim of the integral safety concept is an ambitious one: to realise the vision of accident-free driving.

Active Brake Assist 4: the first active brake assist system with pedestrian detection for touring coaches

Avoiding accidents and protecting more vulnerable road users are central facets of safety development at Daimler Buses. With Active Brake Assist – also called an active braking assist system – and its continuous advancement in the touring coaches from Mercedes-Benz and Setra, Daimler Buses has repeatedly set standards for ten years.

The new Active Brake Assist 4 – ABA 4, for short – with pedestrian detection marks a new high point in the development of assistance systems. Not only will it automatically initiate emergency braking for moving and stationary obstacles ahead, it additionally warns the driver visually and audibly of a potential collision with pedestrians and at the same time automatically initiates partial braking. This gives the driver every opportunity to prevent a collision with a pedestrian: The driver can warn the pedestrian using the horn, initiate maximum emergency braking or steer to avoid the collision.

Multi-mode radar systems with a range of up to 250 m

In technical terms, Active Brake Assist 4 with pedestrian detection is based on new-generation radar technology which also features in the latest Mercedes-Benz passenger cars and trucks. The electronically scanning multi-mode radar comprises long and short-range radar systems. The long-range radar detects multi-track vehicles and obstacles in a direct line in front of the touring coach up to a maximum distance of 250 m, single-track vehicles such as bicycles up to 160 m and pedestrians up to 80 m. The short-range radar has a maximum range of 70 m and is even able to detect pedestrians and vehicles to the sides ahead of the touring coach.

Active Brake Assist: more capable with each generation

The new Active Brake Assist 4 with pedestrian detection is the logical evolution of the existing tried and tested Active Brake Assist 3, which already carries out emergency braking for moving vehicles as well as front and stationary obstacles ahead. Mercedes-Benz caused a sensation with its previous braking systems, from the first Active Brake Assist back in 2008 to Active Brake Assist 3, introduced in 2014. During that time, the system's capabilities have been continually enhanced.

Safety experts understand that Active Brake Assist can save lives. Which is why the legislators reacted to the developments at Mercedes-Benz: Since November 2015, braking systems have been mandatory for newly approved touring coaches and trucks. The new Active Brake Assist 4 with pedestrian detection once again sets new standards with its performance.

ABA 4 from 2019 as standard for touring coaches from Mercedes‑Benz and Setra

Safety is an absolute top priority for Daimler Buses, which is why Active Brake Assist 4 will become standard equipment in all touring coaches from Mercedes‑Benz and Setra from the first quarter 2019: Mercedes‑Benz Tourismo RHD, Setra ComfortClass 500 and TopClass 500 including the Setra S 531 DT double-decker bus.

Preventive Brake Assist, the first ever active brake assist system for city buses

In Preventive Brake Assist, Mercedes‑Benz introduces the first active emergency braking assist system ever for city buses as a world premiere. The new assistance system warns of a potential collision with moving pedestrians as well as of stationary or moving objects, and automatically initiates partial braking. The warning cascade and the braking intervention are designed for use in city traffic.

The operating principle of Preventive Brake Assist

Preventive Brake Assist works similarly to Active Brake Assist 4. However, it is designed for the highly dynamic traffic in city bus transport with a host of widely different road users and directions of movement. In the event of a pending collision with pedestrians or stationary objects, Preventive Brake Assist warns the driver visually with a red triangle showing a vehicle symbol lighting up on the central display. At the same time, the system also emits an audible warning and initiates partial braking. The braking is maintained until the driver intervenes or the bus comes to a stop.

The driver can override an intervention at any time by applying the brakes, executing an evasive manoeuvre with a steering motion, pressing the accelerator pedal or activating the kick-down function. In addition, he can warn pedestrians or other road users by sounding the horn.

Preventive Brake Assist intentionally does not perform an automatic emergency stop. This reduces the risk of injury for standing passengers on the bus and also for the seated non-belted passengers. However, the option of an individually initiated emergency stop is always available to the driver.

The technology of Preventive Brake Assist

Like Active Brake Assist 4, Preventive Brake Assist uses a radar system to detect obstacles or other road users. It is based on a new generation of radar technology. The advantage of this radar system is that it operates independently of the prevailing light conditions and also largely independently of weather conditions. The radar system determines distances and relative speeds with extreme precision, and is also able to see at night and in rain and fog.

The long-range radar detects multi-track vehicles and obstacles in a direct line in front of the bus up to a distance of 250 m and pedestrians up to a distance of 80 m. Vehicles such as motorcycles and cyclists are detectable up to a distance between these two ranges (160 m). The additional close-range radar has a maximum range of 70 m and due to the wide aperture angle of 120 degrees also detects vehicles and pedestrians in front and to the sides of the vehicle.

Preventive Brake Assist detects moving pedestrians in virtually any traffic situation. For example, when they cross the bus's path, step out from behind an obstacle or are moving along the lane. Pedestrians are also detected within the range of the radar system when the vehicle turns off to the left and right.

Warning and braking reactions for stationary and moving obstacles happen over the entire speed range of the bus. Pedestrian detection is active up to a speed of 50 km/h.

Available for the entire family of city buses of the Mercedes-Benz Citaro

Preventive Brake Assist is optionally available for the entire family of models of the Mercedes‑Benz Citaro, including the Citaro G articulated bus, the low‑entry Citaro LE, the inter-city bus Citaro G/GÜ and the large-capacity bus CapaCity. Preventive Brake Assist is also optionally available for the range of the Mercedes‑Benz Conecto city buses.

Sideguard Assist: the first ever turning assist system for city buses and touring coaches

Turning right in city traffic is among the most unpleasant tasks for drivers, as they are required to heed traffic lights and signs ahead while simultaneously observing oncoming and crossing traffic and keeping an eye on pedestrians and bike riders at the side. In addition, the traffic situation can change in a matter of seconds, and cyclists and pedestrians are not always aware that a bus driver may not be able to see them. With this in mind, Mercedes‑Benz and Setra are now the first bus and coach brands to offer the turn-off assist system Sideguard Assist with pedestrian detection. Mercedes‑B enz offers it for the city bus Citaro in all its versions including the large-capacity bus CapaCity and high-deck touring coach Tourismo, Setra for its touring coaches of the ComfortClass 500 and TopClass 500 as well as for the Setra S 531 DT double-decker bus.

The goal is to continuous information, warnings when needed

Sideguard Assist operates in several stages: It first of all informs the driver when a relevant object is located in the warning zone. In a second stage, the driver receives a warning if he initiates or continues an action and a danger of a collision arises.

The centrepiece of Sideguard Assist is a radar sensor system with two short-range radar sensors on the co-driver's side. They are located in the panelling immediately aft of the right front wheel at a height of about one metre above the roadway. The side monitoring zone has a width of 3.75 m. The system covers the entire length of the bus, complemented by two stripes to the front and rear of about 2 m each. Above a speed of 36 km/h, these additional zones are expanded to 5 m at the front and to 15 m at the rear beyond the length of the vehicle, each growing linearly with the speed.

If there is a moving object in the side monitoring zone, the driver is given a visual warning. On the touring coaches, an LED in the shape of a yellow triangle lights up at the driver's eye level in the side mirror on the co-driver's side. On the Citaro, it is integrated into the A0-pillar on the door side. The lamp draws the driver's attention intuitively towards the situation alongside the vehicle. If the sensors detect the risk of a collision, an additional visual warning is given: the LED flashes brightly red several times. After two seconds, it remains permanently illuminated in red. In addition, there is a vibration warning in the driver's seat.

Sideguard Assist also warns of stationary obstacles

A visual and tactile warning also occurs if the sensors additionally detect a stationary obstacle, such as a traffic light or a bollard, in the bus's turning curve when turning. This prevents collisions and expensive repairs. The curve trajectory warning system functions from walking pace up to 36 km/h. The other functions of Sideguard Assist are available from walking pace up to 100 km/h.

For the purposes of its warning cascade, Sideguard Assist also analyses actions by the driver, for example, activation of the indicator on the co-driver's side or the steering movement when turning off, and the distance from a moving or stationary object is assessed continuously while the bus is moving. That is why Sideguard Assist also warns of obstacles when turning off without activating the indicator, for example.

The driver retains full responsibility and remains in control of the situation at all times and is able to take any course of action which appears appropriate.

Sideguard Assist also helps when changing lanes

The new Sideguard Assist offers even more functions: At speeds above 36 km/h, it also warns the driver during lane changes to the right. In this case, the driver is also informed of any object on the co-driver's side or is warned when he activates the indicator. This means that Sideguard Assist provides support when changing lanes, for instance when overtaking a cyclist outside of town, or when changing lanes on multi-lane roads and motorways.