Researchers at Chalmers University of Technology in Sweden have developed a new truck front concept to significantly reduce fatal accidents in car-truck collisions. The new truck facade comes after the European Union regulations regarding the maximum length of the truck were lifted. Crash tests on the front of the new truck were carried out by the Swedish transport administration, Trafikverket, and showed that better truck designs can reduce passenger compartment deformations by 30-60 percent. This reduces the risk of injury and potential death to vehicle occupants.
Fatal accidents between heavy goods vehicles and passenger cars account for 14 to 16 percent of all deaths among vehicle occupants in both the European Union and the United States. In more than 90 percent of traffic accidents involving heavy vehicles, the other party dies, usually in the passenger vehicle. The most common types of these collisions are frontal collisions on rural roads and rear-end collisions on highways (the heavy truck hits the rear of the front vehicle). Therefore, it is important to conduct more investigations into collisions between cars and heavy trucks to improve the survival rates of vehicle occupants in such collisions.
Truck front designed not to kill
It is widely accepted that two modern passenger cars with the best safety standards should be able to handle a collision at 80 kilometers per hour without fatal consequences. This is not the case for collisions between trucks and cars. While the speed is often moderate in truck-car collisions, the severity of the collision is still high due to the geometry, rigidity and overall mismatch between the two vehicles.
In order for a passenger car occupant to survive a head-on collision with a truck, the passenger car cabin must be kept intact. This is not something that can be guaranteed today, even in most modern cars, so new truck interface research aims to find the best ways to protect car occupants, as well as truck drivers, in the future.
Cars and trucks have separate structural elements (bumpers, energy-absorbing beams, and passenger compartment frames) designed to deform and absorb energy or remain intact and protect occupants. It has been observed in real-world crashes that these local structures rarely react the way they were designed. This results in a less efficient crash response. A team of researchers at Chalmers University of Technology has designed a truck interface that will improve the collision process. This latest design is based on previous research conducted at Chalmers.
“We know that providing distributed force over the affected vehicle would allow its crash structures to operate more efficiently. From the first test, we could also see that the energy levels observed were high and that better energy absorption by the truck was needed,” he says. Professor Robert Thompson, Department of Vehicle Safety at Chalmers University of Technology, said another challenge was also trying to steer the car out of the front path of the truck.
New EU regulations allow for change
The new interface was designed with the aim of demonstrating potential design principles that will be interpreted and adapted by manufacturers.
“The interior design of the new truck’s fascia is made of aluminum honeycomb. This is a structure consisting of repeating hexagonal tubes made of aluminum foil. This is ideal for a lightweight, energy-absorbing structure, since about 97 percent of its volume is air. Honeycomb is used Made of aluminum in several crash test barriers to provide distributed strength and energy absorption by varying the thickness of the foil, we can change the strength and deformation properties and have the manufacturing flexibility needed to create “one-of-a-kind” prototypes and “proof of concept,” says Professor Thompson .
One of the main contributions was to take advantage of the new truck dimension regulations in Europe which were amended in 2019 (Decision (EU) 2019/984). This relaxed the previous maximum truck range length, leading to the emergence of “flat-front” trucks in Europe that increased the cargo space on the truck within a fixed length. This has resulted in limited design space and few opportunities to incorporate impact-resistant designs, such as those found in passenger cars, into trucks.
Unique tests have shown 30-60 percent less impact in crashes
The new truck interface has been tested by the Swedish transport administration, Trafikverket, at the Autoliv test track in Vårgårda, in a set of unique tests. The tests showed measurable results and clearly highlighted that the new truck interface made a big difference. Crash tests have shown that better truck designs can reduce passenger compartment deformations by 30-60 percent, reducing the risk of injury to vehicle occupants. Truck deformation in sensitive areas is also reduced and truck driver safety and cargo security are improved. Steering, brakes and suspension components are at risk of damage if they are not protected. Protecting these components reduces the risk of subsequent accidents or even a truck rollover.
“A truck is involved in every fifth fatal accident in road traffic. Although trucks represent only 6 percent of the traffic volume in Sweden where the tests were carried out, about 45 people die annually in traffic accidents involving heavy trucks, and in Over 90 percent of these accidents it is the other party who dies, usually in a passenger car. The goal is to develop a standard for crash tests for trucks that could be entered into Euro NCAP consumer tests in 2030. We want people in a passenger car to be able to survive. A direct collision with a truck because the vehicle cabin remains intact,” says Rikard Fredriksson, senior consultant at Trafikverket and associate professor at Chalmers.
The test was based on the collision of a modern passenger car and a heavy truck at speeds that could lead to a fatal accident. The crash test was conducted at 50km/h but simulates an original cruising speed of 80 which has been reduced by 30km/h by the automatic emergency braking (AEB) systems required on newer cars and trucks.
Chalmers University of Technology, the Swedish Transport Administration and the automotive industry are working together to further develop tests with the front of the truck.
Previous research and basic information:
Truck interface research: From Chalmers University of Technology, Professor Robert Thompson was assisted by MSc Mobility student project groups in 2022 and 2023. Christopher Mroz of Autoliv Research was also involved in designing the front body to provide simulation expertise.
Previous crash tests: The first truck-car crash test showed how the loading between the two vehicles was concentrated on a few structures that were overloaded and caused unwanted deformation of the surrounding structures. For the car it was the left front wheel and the driver’s door area and for the truck it was the suspension and steering system. The new truck front design improved force distribution and reduced positional distortion.
The European New Car Assessment Programme, known as Euro NCAP, is an organization that evaluates the safety of new vehicles in Europe. The company was first established in 1997 for the UK Department of Transport, with the aim of carrying out independent security tests on new cars but was later supported by most European countries. Now, the company provides the most reliable reviews and ratings regarding the safety of new vehicles, and its testing over the years has improved standards.
Tests being carried out in Sweden: In 1997, the Swedish Parliament adopted a vision that no one would be killed in traffic – Vision Zero – and since then the number of road deaths has fallen by almost two-thirds. Sweden currently has a death rate of 1.9 road deaths per 100,000 population in 2020. This, along with Norway, is the lowest road death rate in the world. Vision Zero expects people to make mistakes, so the transportation system must be designed using biomechanical limits. This facilitates an environment in which crashes involving safe vehicles, safe infrastructure and safe road users do not result in the death or serious injury of individuals.
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For more information please contact:
Robert Thomson, Professor, Department of Vehicle Safety, Department of Mechanics and Marine Science, Chalmers University of Technology, Sweden robert.thomson@chalmers.se, +46 31 772 36 45
Rikard Fredriksson, Assistant Professor, Department of Vehicle Safety, Department of Mechanics and Marine Sciences at Chalmers University of Technology, and Senior Traffic Safety Expert at the Swedish Transport Administration / Trafikverket rikard.fredriksson@trafikverket.se +46 10 123 17 26
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