By: Fabian Cotter

STANDEES’ SAFETY during any emergency bus situation is at the forefront of the thinking behind Daimler’s new optional Preventative Brake Assist feature for all Euro Citaro and Conecto Mercedes-Benz city buses, the company announced recently.

Daimler's Preventative Brake Assist feature is designed to minimise impact on passengers.

Preventative Brake Assist cleverly applies a warning system and only partial braking automatically in the event a vehicle needs to rapidly reduce speed before coming to a halt – the latter still at the directive of the driver.

In doing so, the impact of the kinetic energy and momentum on passengers standing on packed buses is lessened, no doubt reducing the chance of them being ‘thrown around’ and incurring unforeseen injury.

The overall product safety roll-out will see the new Active Brake Assist 4 - 10 years in development and now also automatically initiating a braking manoeuvre for pedestrians in the form of partial braking - as standard from 2019 on all touring coaches from Mercedes-Benz and Setra, with the new Preventive Brake Assist now optional for city buses.

Additionally, on both buses and coaches, Sideguard Assist – the first turning assistance system for city buses and touring coaches, it’s claimed – is optional.

According to Daimler, "preventing accidents and protecting more vulnerable road users … is the utmost priority in the safety concept of the premium bus and coach brands Mercedes-Benz and Setra."


Active Brake Assist was the first emergency braking assistance system for buses and coaches when it was introduced 10 years ago as an option, and in its fourth generation is now being transferred to all touring coaches from Mercedes-Benz and Setra, says Daimler.

Active Brake Assist was enhanced with each generation. Whilst it at first initiated emergency braking only for moving vehicles ahead, Active Brake Assist 3 initiated automatic emergency braking for stationary obstacles in addition, and was thereby capable of actively preventing even more accidents, it’s stated. Active Brake Assist was one of the main triggers for the mandatory introduction of automated emergency braking systems in touring coaches from autumn 2015 in the EU, it says.

The new Active Brake Assist 4 is the first emergency braking assistant for buses and coaches to automatically initiate a braking manoeuvre for pedestrians, too. As explained by the company, "in this case all options are open to the driver: warn the pedestrian using the horn, evade them with the bus or carry out an emergency stop. The basis for ABA 4 is the multi-mode radar system with a combination of long-range and short-range radar."

Till Oberwörder, head of Daimler Buses, said: "By taking this step, we are making our already safe buses and coaches even safer. We are certain that Active Brake Assist 4 will not only prevent accidents, it will save lives."

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Preventive Brake Assist applies to city buses and is the first active emergency braking assist system ever for city buses as a world première, says Daimler.

The new assistance system warns of a potential collision with moving pedestrians, as well as with stationary or moving objects, and automatically initiates partial braking if there is a critical risk of collision, it explains.

The ‘warning cascade’ and the braking intervention are designed for operations in city traffic; hence why Preventive Brake Assist intentionally does not perform automatic emergency stops. This reduces the risk of injury for passengers in the bus, in particular for standing passengers. The driver still has the option of an emergency stop at any time, says Daimler.

Preventive Brake Assist is available as an option for the entire model family of the Mercedes-Benz Citaro, including the CapaCity large-capacity bus. Preventive Brake Assist is also optionally available for the range of the Mercedes-Benz Conecto city buses.


Sideguard Assist is the first turning assistance system for city buses and touring coaches, says Daimler.

As explained, "turning … in city traffic is among the least unpleasant [sic] 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 bicyclists to 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 possibly 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 optional turning assistance system Sideguard Assist with pedestrian detection. Mercedes-Benz offers it for the city bus Citaro in all versions including the large-capacity bus CapaCity and for the high-deck touring coach Tourismo. Setra offers it for its touring coaches of the ComfortClass 500 and TopClass 500 including the Setra S 531 DT double-decker bus."


Sideguard Assist operates in several stages: 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 and in the instrument cluster. On the Citaro, it is integrated into the A-pillar on the door side. The lamp draws the driver's attention intuitively towards the situation alongside the vehicle, it’s claimed.

If the sensors detect the risk of a collision, there is an additional visual warning in the form of a red triangular LED, as well as a vibration warning in the driver's seat. The centrepiece of Sideguard Assist is a radar sensor system with two short-range radar sensors on the co-driver side. They are located in the trim immediately aft of the right front wheel. The side monitoring zone has a width of 3.75m.

On the city bus, the system covers the entire length of the bus, complemented by two strips to the front and rear of about two metres each. On the touring coach, in addition to the entire length of the vehicle, an area of five metres in front of and up to 15 metres behind the bus is always covered, Daimler says.

Both Active Brake Assist 4 and Sideguard Assist were presented by Daimler Buses as a world première in 2017 at the launch of the new Setra S 531 DT double-decker bus (as featured on the cover of Australasian Bus & Coach magazine Issue 369).

The two assistance systems are now transferred to other model series of the Mercedes-Benz and Setra brands.

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