Engineering for Safety: Advances in crash test technology.

A modern car should provide both the driver and passengers with a high level of protection in the event of a possible collision or accident. Crash tests are aimed at practical verification of how the tested car model performs in terms of safety and durability in such situations. The importance of this type of project is evidenced by the fact that they have been performed since the 1950s. With each successive decade, their level of sophistication has increased, which translates into an increase in the safety of both the users of a given car and other traffic participants.

Currently, car crash tests are conducted not only by the manufacturers but also by independent organizations such as the European New Car Assessment Programme (Euro NCAP). Depending on the entity that conducts the crash tests, their list and the parameters tested may vary, although the aim is to subject vehicles to the most comprehensive verification and evaluation of the resilience and safety provided to the driver and passengers both in a crash and in standard use. Over the years, crash test technology has been evolving – this has increased the quality and reliability of such tests and has also resulted in more intensive efforts by car companies to improve the safety of their cars and to search for new and better materials that will provide more effective protection for car users.

The remainder of this article will explain, among other things, what exactly car crash tests are, the basic types, how they are conducted, and what innovations in crash test technology and materials to enhance vehicle safety we have seen in recent years.

What are car crash tests?

Almost every day we receive information about car accidents that occurred on Polish or foreign roads. The first such fatal event occurred as early as 1889 in Great Britain, and by the 20th century, fatal accidents had become a tragic part of the reality around us. With the development of automobile traffic, more and more emphasis began to be placed on the issue of vehicle safety, which is now an absolute priority for the entire automotive sector. Natural consequences of this trend include:

• the development of crash test technology and regulations in this area,
• increased efforts by automakers to find new materials and technologies that can improve the safety and durability of the vehicles they produce,
• increased awareness of car users themselves, who are not only guided by the safety aspect when choosing a new car but are also interested in solutions, such as the crash test simulator, aimed at raising awareness of the risks associated with car crashes and accidents and promoting responsibility “behind the wheel.”

In the process of increasing the safety level of cars, a huge role is played by car crash tests (crash tests). In the simplest terms, these are specially designed tests carried out under strictly defined conditions, which are designed to mimic as closely as possible specific traffic situations, such as collisions or accidents. These tests may examine not only the vehicle’s behavior under the impact of certain forces on it, but also the effects of this impact on drivers, passengers, or pedestrians, for example. It is worth noting that the methods used for specific tests differ not only because of the type of simulated traffic situation or the entity conducting the tests but also, among other things, because of the type of vehicle. For example, crash tests on trucks will differ from those on passenger cars, just as tests on internal combustion vehicles may differ from those on electric cars.

What are car crash tests for?

There are various reasons that new cars undergo crash tests. The primary reason is the desire to verify the safety and resilience of manufactured vehicles before they are put on the market. Detection of imperfections allows necessary changes to be made to the design or manufacturing technology to improve the level of car durability and the protection it provides to the driver and passengers.

Another reason that determines the important status of car crash tests is legal regulations. These require auto manufacturers to test their vehicles to meet certain crash standards. Failure to meet these standards prevents the tested car from being allowed to operate in the country where the regulations apply.

An important motivation behind independent entities that specialize in conducting car crash tests is to make potential users of specific models aware of how they perform in terms of safety. For example, thanks to the stars awarded by Euro NCAP, a person interested in purchasing a vehicle can verify that the car he or she has been considering is capable of providing him or her and his or her family with an adequate level of protection while on the roads.

How are car crash tests conducted?

Independent institutions are usually responsible for conducting crash tests. One of the most important entities with this profile is the Euro NCAP – European New Car Assessment Program, whose tests are carried out on cars of many popular brands. By familiarizing yourself with the characteristics of basic car crash tests performed by this institution, you can better understand what crash testing is all about.

One of the basic tests Euro NCAP subjects the vehicles it tests to is the off-set (front impact) frontal crash. It includes two separate tests:

• the first test involves a full frontal impact with a stationary wall at a speed equal to 50 km/h.
• the second test involves a vehicle colliding with a mobile obstacle weighing 1,400 kg. This choice of obstacle parameter is intended to mimic the average car with which a collision on the road can occur. Two details are important in this case: the speed of movement of the car and the obstacle is equal and is 50 km/h, and the impact area is 50% of the front surface of the vehicle.

Another test carried out by Euro NCAP is the side impact test. In this case, the test involves hitting a 900 kg barrier against the side of a stationary vehicle at the level of the center body pillar. The barrier moves at a speed of 50 km/h during this test.

An important part of the set of tests conducted by Euro NCAP is the pole test (field test). What does it consist of? During this test, the car travels sideways at 29 km/h and then hits a vertical obstacle at the level of the center body pillar.

Among the Euro NCAP tests, the pedestrian impact test was also not to be missed. During this test, a pedestrian is simulated to be hit by the front of the car at a collision speed of 40 km/h. The pedestrian’s role in this case is played by a specially constructed dummy, which imitates the figure of an adult or child.

It should be noted that the above four tests do not exhaust the pool of all tests that new vehicles can undergo. Crash tests can also create simulations of many other situations, such as roofing, driving into a tree, or driving a car into the back of another car, among others. What’s more, institutions such as Euro NCAP also subject cars to other tests that allow a reliable assessment of their safety. As examples of such tests, we can cite, among others:

• test of child safety systems,
• a test of speed assistants and unfastened seatbelt reminder systems,
• test of automatic braking systems,
• test of vehicle stabilization control systems,
• a test of systems that examine driver fatigue and distraction.

But returning to the basic set of crash tests conducted by Euro NCAP, the cars subjected to them are evaluated by awarding the appropriate number of stars (scale from 1 to 5). It is worth noting that the institution is aware of the continuous development of crash tests – it takes an active part in them – so the ratings it awards to individual car models are not “eternal” – after six years they reach the statute of limitations. From what angle are cars taking part in Euro NCAP tests evaluated? Several areas are evaluated on a percentage basis, which include:

• protection of adult passengers,
• child protection,
• Protection of other road users,
• assistance systems.

The sub-ratings later translate into an overall number of stars awarded to the tested car model.

Innovations in crash testing

The dynamic development of the automotive sector and the associated increase in the safety level and vehicles’ durability means that car crash tests must also evolve and constantly “raise the bar” for the cars being tested. This is also dictated by successive regulations aimed at increasing the safety of road traffic and its participants. Institutions specializing in conducting such tests are constantly working on developing testing technologies, modifying both the methods and types of tests themselves, as well as adding more factors to be verified and evaluated. What examples of innovations in the area of car crash tests are worth paying special attention to?

Numerical models representing the human body

Surrogates of the human body or crash dummies designed to simulate passengers, play an important role in car crash tests. This is one area where particular development potential is seen in terms of improving crash-tests and enhancing their usability. Developments in this area involve not only the design of the dummies themselves, but also, for example, numerical models mapping the geometry and properties of specific parts of the human body. One initiative worth noting was the European Union-funded THOMO project to develop a numerical model of the human chest, that is, the entire area between the head and abdomen. The results of the research carried out as part of this project have led to a better knowledge and understanding of the responses of human bodies with different physical parameters to the forces acting on them during crashes, which in turn has fueled the development of work on crash dummies with better biological fidelity.

Mannequins simulating the female figure

An interesting example of innovation in crash testing, which takes into account a factor that has been downplayed for years, are mannequins that simulate the female figure. For a long time, such models of the human body were usually based on the parameters and body structure of the average male. Meanwhile, it is estimated that today about half of the drivers are women, who are not only smaller and lighter on average than men, but also characterized by, among other things, different muscle strength or shape of the torso, pelvis, and hips. All this makes their bodies react differently to the stresses they face during dangerous traffic incidents.

This is perfectly evident in low-force rear-end collisions, one of the more common types of collisions on the road. Studies show that in such collisions there is a significant difference in the disadvantage of women in terms of the level of risk of cervical spine injury. The group of Swedish specialists conducting this research, led by Astrid Linder, has developed a special dummy that replicates the body of an average woman. It is being used in crash testing, and it is possible that it will contribute in the near future to a greater focus by auto manufacturers on testing their vehicles for the safety provided to women. Currently, some car companies, such as Mercedes-Benz, have already been using dummies simulating a woman’s body in crash tests of the vehicles they produce for years, but due to the lack of relevant legal regulations, this is not a fully common practice in the automotive sector so far.

Classic solutions instead of touch screens

Over the past few years, automakers have been eager to expand the range of features in their vehicles that required activation using touchscreens and surfaces. This was intended not only to modernize the design of car interiors but also to increase driver convenience and reduce production costs. However, according to Euro NCAP specialists, the trend associated with the move away from traditional buttons and switches to touch-sensitive solutions has in practice contributed to greater distraction for drivers, and thus an increase in the risk of accidents. For this reason, already in 2026, a mandatory condition to allow a new car model to contend for the maximum number of stars in Euro NCAP crash tests will be the use of manual switches, levers or buttons that operate a minimum of five important functions, such as operation:

• turn signals,
• emergency lights,
• windshield wipers,
• horn,
• emergency call function.

Virtual car safety tests

There is no denying that more and more areas of our lives are in some way entering the virtual world. The same is true in the automotive sector – industrial design of cars is based on CAE analysis or parametric CAD modeling, among others, and actual crash tests are supported by advanced simulations. Virtual car safety tests bring many benefits related to, for example:

• reducing costs – virtual car safety tests reduce the number of actual crash tests, thus reducing losses associated with damaged vehicles, among other things,
• the ability to analyze various factors in detail – thanks to simulations, it is possible to check how given components will behave under specific parameters, as well as under the influence of set forces or other factors acting on them, which in turn allows you to refine individual components of the car until the optimal form is achieved,
• ecology – a reduction in the number of actual crash tests is also associated with less waste production in the form of parts of damaged cars,
• the safety of conducting the test – any real vehicle collision, even implemented under controlled conditions, carries a certain risk to the environment, including the measuring apparatus, which is not present in the case of virtual safety tests.

Toyota engineers, who are the authors of the THUMS (Total Human Model for Safety) system, are taking an active part in the dynamic development of virtual car safety tests. This is a continuously improved virtual crash system, commonly referred to as digital or virtual dummies, which allows the creation of various digital models of the human body characterized by a very high accuracy of biological reproduction. The model developed with its help can reflect not only the assumed size or shape of the human body but also, among other things, the position, density, and sensitivity of muscles, bones, and organs. What is noteworthy, with THUMS it is possible to prepare, for example, a model of a child, pregnant woman, or senior citizen, and then track and analyze data from about 20 million points on the body and inside the body of such a virtual “passenger.” Using such a model, engineers have the ability to analyze the impact of various types of collisions and accidents on specific organs of the “passenger,” taking into account how tight his muscles are. We are not able to carry out such a thorough study on the basis of – even very modern – conventional crash dummies.

What modern materials are used to make safe cars?

Auto manufacturers striving to increase the level of protection their vehicles provide to drivers and passengers are constantly working on exploring new and improving already-known materials used to manufacture various automotive components. What materials are worth paying special attention to in terms of car safety and durability?

High or ultra-high-strength steel

One of the most widely used material groups in the automotive industry is steel. This is due to a number of advantages of these materials, which include high strength or excellent energy efficiency. Of course, steel is not equal to steel, which is why automotive components responsible for passenger safety, which must have particularly good strength properties, are primarily used:

• high-strength steels, such as BH or HSLA – are used for, among other things, thresholds, floors, side posts, and other components that contribute to controlled crush zones,
• ultra-high-strength steels, such as AHSS – like BH or HSLA, are used in the production of automotive parts crucial from the perspective of passenger safety, while their additional advantage is that they can contribute to reducing vehicle weight (exceptional strength allows the use of thinner sheet metal).

Plastics

It is difficult to imagine today’s automotive world without strong, durable and lightweight plastics. They are used both in the manufacturing of exterior automotive components, such as spoilers and bumpers, and for the production of interior car equipment, such as headliners, carpets and headrests. Which plastics are particularly popular for components that play an important role in the context of car safety? Among them are:

• polyphenylene sulfide (PPS), is used, for example, in the manufacture of pumps, valves, and various fuel system components critical to the safe operation of autos,
• polypropylene with EPDM, used, for example, in the manufacture of heavy-duty bumpers,
• foamed polypropylene (EPP), used to make components designed to absorb energy, such as in car doors.

It is worth mentioning that components made of plastic are often reinforced by so-called reinforcement with various types of metallic or ceramic fibers, which further improves their mechanical characteristics.

Composites

Another important group of materials being considered in the process that is designing a car are composites. An excellent example of an innovative composite used, among other things, for body components or drive shafts, is carbon fiber. It is characterized not only by high strength, but also by its lack of susceptibility to corrosion, very low weight or unique aesthetics. Another composite material eagerly used in the automotive sector is Kevlar, or aramid fiber, which offers even better strength properties, as well as high thermal and friction resistance and extremely low weight. Due to its qualities, Kevlar is used to reinforce timing belts and other important parts of the car’s structure.

Safety vs. car design

Increasingly demanding crash tests, as well as the desire to provide customers with high-quality, safe vehicles while maintaining cost-effective production, are influencing the multi-stage car design process. Among other things, computer analysis and simulation now play a large role in it, and are used both when designing individual car components and the entire vehicle. Focusing on the optimization of individual automotive components and then correctly implementing the best version of them in the design of the car is very important in the context of the vehicle being able to provide its users with high safety standards.

Designing and then implementing a safe automotive component with the desired characteristics into production requires a comprehensive approach and the involvement of a qualified team of engineers in a given technology project. As Endego, we can provide professional support from experts with many years of experience in leading and implementing technology projects for the automotive sector. We provide comprehensive engineering services, where we actively participate in all phases of the project – from the preparation of the initial concept to the start of serial production.

Would you like to enlist the help of competent engineers and designers to support you with components that can contribute to a marked improvement in the safety of your company’s project car? Get in touch with us!