May 15, 2006 As ironic as it seems, Mercedes Benz trucks are actually more advanced in their active safety systems than the company’s most advanced passenger vehicles, and the advent of its latest Active Brake Assist (emergency brake assistant) technology will see that brought firmly into focus in coming weeks as the company steps up its road safety initiatives at a political level in Europe. Though it will be marketing all of its electronic driver support and safety system concepts in one “Mercedes-Benz Safety Truck” package, the bright yellow safety poster child is actually available as of this week as a fully-optioned Actros. The newly added Active Brake Assist is based on the existing radar system used by the Telligent proximity control system and initiates emergency braking when there is an acute risk of a collision with a car in front.
It uses the three radar beams of the proximity control system, which detect obstacles moving in the lane ahead of the truck at a distance of up to150 metres, while constantly determining the difference in speeds between the two vehicles. If an accident is unavoidable in the prevailing circumstances, the driver is first given a visual and acoustic warning, followed by partial braking (30 percent braking performance), and if the risk of a collision increases even further, the system then initiates full emergency braking. Since rear-end collisions represent a sizable proportion of the accidents that occur in heavy-duty transport on European roads, the accident researchers expect the widespread use of Active Brake Assist to lead to a noticeable reduction in the number of accidents involving fatalities and serious injuries.
In the coming weeks, the Mercedes-Benz Safety Truck will be presented in 12 European countries, and the effectiveness of the safety technologies will be demonstrated in specially organized drives. The aim of this initiative is to encourage the widespread adoption of modern safety systems for accident avoidance by addressing policymakers, the general public, the transport sector and insurers.
“With our roadshow, we’d like to draw attention to the great importance of safety systems in trucks and enter into a dialogue with the various interest groups”, said Andreas Renschler, member of the Board of Management of DaimlerChrysler AG with responsibility for the Truck Group and Buses. “Traffic can be made even safer through the use of assistance systems. Any accident injury or traffic fatality is one too many.”
Following the introduction of ABS, EPS and ASR in the 1980s and electronically controlled braking systems with disk brakes ten years later, more safety and assistance systems were launched for Mercedes-Benz trucks beginning in the year 2000. These included the Lane Departure Warning System, the Stability Control, the Roll Control and the Proximity Control.
Since rear-end collisions represent a sizable proportion of the accidents that occur in heavy-duty transport on European roads, the accident researchers expect the widespread use of Active Brake Assist to lead to a noticeable reduction in the number of accidents involving fatalities and serious injuries.
In contrast to the proximity control system, the Active Brake Assist initiates emergency braking when there is an acute danger of a rear-end collision with a vehicle ahead. It uses the three radar sensors of the proximity control system, which identify moving obstacles within a defined range in front of the truck and in the process continuously determine the speed relative to the vehicle ahead. If the traffic situation does not change and an accident is unavoidable, the driver first receives a visual and an audible warning. If the risk of a collision increases, partial braking (30% of braking power) is initiated to give the driver a further warning. If the driver still fails to react, the system automatically implements an emergency stop. Although the Active Brake Assist (emergency braking system) cannot actively prevent accidents, the application of the full braking power can reduce the collision speed and, therefore, the severity of the accident and its consequences.
No other commercial vehicle manufacturer in the world invests more in the development of new safety systems than DaimlerChrysler. Moreover, active safety is always a focus of development. The task is to prevent accidents from the outset or, alternatively, to develop systems that intervene automatically in order to greatly reduce the immediate effects of accidents.
The effectiveness of such assistance systems is undisputed, yet the number of them installed in vehicles is much too low. “Among other factors, this is because the transport companies that would choose to install safety technologies are still offered too few incentives to do so”, said Renschler. He therefore advocates that everyone who profits economically from reduced accident figures should also work toward making their use more widespread. That means the insurance industry, from the auto insurers to the providers of health and life insurance to the employers’ liability insurance associations.
Responsibility for road safety lies at the political level, Renschler adds. Among the possibilities are incentives, such as reduced insurance premiums, discounts in tolls, or also direct investment aids for the transport companies, such as from the truck toll. The commercial vehicle manufacturers have taken the initiative and have already incurred costs: The safety technologies have been developed and are being offered at low package prices, with a discount of up to a third — as in the case of the safety package for Mercedes-Benz trucks. Renschler continued: “We expect these technologies to lead to a reduction of over 50% in the severity of the consequences of accidents.” At the end of July, DaimlerChrysler will present detailed data from an integrated field test.
Brake Assist, cruise control and hill-holder as standard in many markets
The current-generation Mercedes-Benz Actros offers an even greater safety potential. Depending on the market, the braking system also includes the Brake Assist (BAS) function as standard. It recognises the driver’s emergency braking intention from the speed with which the brake pedal is operated, and instantly builds up the full brake pressure available. The Telligent braking system also includes acceleration skid control and a hill-holder which enables the driver to move off safely on a gradient, without the vehicle rolling back as he changes from the brake pedal to the accelerator. In addition, the standard drive and braking cruise control keeps the vehicle speed constant both on the level and on downhill gradients, the latter being a particularly important safety feature.
The optional retarder as an auxiliary brake significantly improves braking performance compared to the standard engine brake. The system is wear-free, which increases safety, reduces wear on the brake linings and therefore minimises downtimes. The optional electronic level control system ECAS reliably keeps the Actros horizontal under any load conditions.
Good visibility as a safety feature
Good visibility is a major factor in accident prevention. With their large field of view, the exterior mirrors of the Actros already meet the future ECE regulation 46/02. Clear-lens headlamps with free-form reflectors provide optimal illumination of the road surface. On request, Actros models with air suspension are available with xenon headlamps for a further significant improvement in road illumination. The accompanying headlamp cleaning system improves safety even further.
Visibility is improved for other road users by the spray guards in the wheel arches, which effectively prevent clouds of spray on wet roads. The optional daytime driving lights are already mandatory in many European countries, at least during the darker months of the year. These help other road users to see the truck under unfavourable lighting conditions, e.g. when the sun is low or when driving along tree-lined avenues.
Driver-fitness safety thanks to a well-designed cab
The fitness and alertness of the driver are no less important for safety. Driver-fitness safety is ensured by the carefully designed cab of the Actros, with exemplary ergonomics, a high level of ride comfort, an air suspension driver’s seat and, not least, extremely comfortable, back-stress-relieving berths. The standard appointments of the L-cab and Megaspace cab include a manually adjusted air conditioning system, with automatic climate control available as special equipment for even greater comfort. The same applies to the auxiliary air conditioner, which even makes an overnight stop in the Actros a pleasure on hot summer days.
Numerous electronic support and safety systems
In recent years the Actros has caused a sensation with its optionally available, electronic driver support and safety systems. The Telligent Lane Assistant warns the driver when the vehicle is in danger of leaving its lane unintentionally. For this purpose it uses a camera to constantly monitor the distance between the vehicle and the lane markings. If the truck appears likely to cross the lane marking, the driver is alerted by a noise similar to that produced by a corrugated surface on the relevant side.
The Telligent stability control function of the Mercedes-Benz Actros is the equivalent of the Electronic Stability Program (ESP) installed in the passenger cars. Within the physical limits, it prevents a semitrailer combination from developing a skid. A sensor detects any tendency to oversteer, whereupon the stability control system first reduces the engine power and then applies brake pressure to specific wheels to keep the vehicle on course. It also intervenes in the braking system of the semitrailer.
Telligent proximity control relieves driver workload on motorways and other trunk roads. When the system detects a slower-moving vehicle ahead, it automatically brakes the truck with a maximum of 30 percent braking power until a specific distance previously set by the driver has been restored. If the vehicle ahead accelerates, or if the truck driver changes to a clear road lane, the proximity control system automatically accelerates the truck back to its preset speed. This system is also the basis for the new emergency braking aid Active Brake Assist.
Proximity control, the Lane Assistant and stability control are major highlights in today’s support and safety systems. In order to establish these in the market as quickly as possible in the interests of improved traffic safety, the German sales organisation is for instance offering them as a safety package for the Actros in conjunction with a driver airbag, at a 40-percent discount compared to the individual prices – safety is therefore already well worthwhile at the procurement stage.