Safety research for trucks: Truck crash testing as a challenge

Nov 30, 2016

The new TFS also allows Mercedes-Benz to carry out truck crash tests in an enclosed hall for the first time. Thanks to numerous safety and assistance systems, the number of accidents involving trucks has been declining for years. But passive safety is also of great importance for trucks.

Daimler AG has been a pioneer in safety and assistance systems for decades, also in the truck sector. Accident prevention is a central consideration in truck development, for reasons of size and weight alone. The focus is also on mitigating the consequences of accidents. This makes crash tests indispensable, and Mercedes‑Benz Trucks has been systematically conducting these for years. With the new crash complex in the TFS in Sindelfingen, Mercedes‑Benz Trucks is now able to carry out in-house crash tests with trucks under ideal conditions.

"With these crash tests, our engineers will be able to achieve further decisive advances in the safety development of our trucks," says Prof. Dr Uwe Baake, Head of Product Development at Mercedes-Benz Trucks. He is convinced that "we save lives with the findings obtained from these crash tests".

Passive safety, i.e. mitigating the severity of accidents for the vehicle occupants, is a central aspect of the crash tests in the new technology centre for vehicle safety (TFS) in Sindelfingen. Particularly for heavy commercial vehicles, the new crash complex offers unrivalled possibilities. For the first time, the TFS allows reproducible crash tests irrespective of the weather and lighting conditions.The TFS has plenty of space and safety zones for tests with a wide range of vehicle and obstacle configurations at various angles and speeds. Not least among the advantages is the ability to document each crash test on film. This provides the basis for detailed analyses of crash tests and their results, and therefore for possible improvements.

Prof. Dr Uwe Baake: The new technology centre for vehicle safety raises the already highly sophisticated safety development process for Mercedes-Benz trucks to another new level.

The technology centre for vehicle safety (TFS) also conducts crash tests with trucks

The three-axle Mercedes-Benz Actros 2548 L tractor unit with a mounted swap body impacts the platform semitrailer at 30 km/h. The cab rears up and is pushed to the rear by the impact. The basic structure of the cab is maintained, as is the driver's protective space. The door can be opened, and in a real accident the driver would be able to exit the vehicle unassisted. The twelve-tonne series production truck impacted the 20-tonne mock-up of a platform semitrailer with a full overlap.

A second crash test, this time with a two-axle Mercedes-Benz Actros 1845 LS semitrailer tractor. The procedure is the same, but the impact speed is 40 km/h against a movable mock-up of a platform semitrailer. The result of this second, more stringent test is about the same: once again the cab rears up and is pushed rearwards on its mountings. And once again the measured values for the belted dummy driver remain in the low range.

These impact tests with the two Actros models were the first truck tests conducted in the new complex. They reproduced a highly realistic situation: a truck driver is suddenly confronted with the end of a traffic tailback, and while he or the emergency braking assistant included as standard are able to initiate emergency braking, the truck is unable to stop in time and collides with a stationary semitrailer combination at half motorway speed.

Truck crash testing as a challenge – a new dimension of its own

Crash tests with heavy trucks pose particular challenges for the safety specialists at Mercedes-Benz. This is mainly due to the size and weight of the test vehicles: A typical semitrailer tractor for long-distance operations weighs around 7.5 t, about as much as five Mercedes-Benz C-Class passenger cars. Tractor units with bodies are all the heavier. A width of around 2.55 m and a vehicle height of up to 4.0 m is also a new dimension.

Moreover, there are hardly any standardised requirements or passive safety tests prescribed by the licensing authorities. Neither is there an independent test institution like Euro NCAP. At present the authorities only prescribe a pendulum impact test according to ECE R 29/3 for trucks, with a 1.5 t weight impacting the front and roof of the cab and a 1.5 t weight impacting the A-pillars. These tests simulate both a frontal impact and a capsize onto one side. A standardised survival space must be maintained for the driver during these tests. All Mercedes-Benz trucks are certificated to ECE R 29. In addition, the developers and safety experts at Mercedes-Benz Trucks have developed their own standards and tests – always taking their lead from what happens in real accidents.

Advantage due to networking within the company

The advantage held by Daimler AG vehicles in the field of safety development is no accident. The individual divisions and business units enjoy a particular benefit: Trucks, vans, buses and also cars are closely networked with each other, and with the central research activities. This means that each business unit benefits from the developments and experience of the others.

For example, in spring 1995 the electronic stability system ESP® entered series production in the Mercedes-Benz S-Class as a world first. Only a few years later this was followed by much more complex versions in trucks, vans and buses, owing to a wide range of model variants with different wheelbases, axle configurations, bodies and loads. ESP® has now been in successful use for 20 years, and is a standard feature.