Active & passive safety technologies
ZF has specific expertise in the development of intelligent safety systems
Independent organizations like NCAP test the safety of new vehicles. Their work helps reduce the number of people injured or killed in traffic accidents – and also inspires automakers and their suppliers to produce even more impressive innovations.
As we enjoy watching Formula One races in our living rooms, we become almost subconsciously aware of the latest advances in automotive safety. Because nowadays, when an F1 race car is involved in a pile-up or careens off the track and into a pile of tires at a cool 200 mph, the driver usually walks away from the wreckage unscathed. Although enormous forces are acting on the race car’s structure, the fragile human body within is protected from injury by state-of-the-art automotive architecture. And yet just a few decades ago, such accidents would undoubtedly have been fatal. In terms of design, a standard car has nothing in common with an F1racer. But our understanding of the factors necessary for a driver’s survival, plus the enormous gains in computer processing power, have dramatically improved vehicle safety on the streets.
Back in 1985, annual road traffic accidents resulted in some 10,000 fatalities in Germany alone. But by 2015, the number of traffic fatalities had fallen by almost two thirds to just under 3,500 – even though there were almost twice as many vehicles on the road.
The U.S. saw a similar trend: over the same period, the number of motor vehicles in the country rose by around 100 million, whereas the number of road deaths fell by some 20 percent. One of the institutions that made a significant contribution to this trend was the New Car Assessment Program, better known as NCAP.
What may seem like a single consumer protection organization spanning the globe is actually made up of 10 independent rating agencies that specialize in assessing the safety-related features of new automobiles. The individual agencies were founded between 1978 (U.S. NCAP) and 2006 (China’s C-NCAP). They developed test protocols to standardize the crash properties of cars. Tests focus on vehicle occupants; the safer they are, the higher the number of points awarded. Crash-test ratings take the form of stars, with a maximum score of five stars. And nowadays, vehicles with low ratings are almost impossible to sell.
However, test criteria are not identical in every country – and never have been. Each NCAP organization sets different priorities based on regional needs and the most common types of accidents there. Thus U.S. accident statistics show significantly more single-occupant accidents due to, for example, solo drivers becoming tired, accidentally veering off the endlessly long highways and rolling their vehicles. That’s why vehicle rollovers are an important part of the U.S. NCAP test.
In Europe, accidents involving other road users are more common, so Euro NCAP test scenarios focus more closely on them.
But NCAP organizations also help inspire engineers and legislators. For example, NCAP has gradually paid more and more attention to electronic driver-assist systems such as the electronic stability program (ESP), extending the scope of assessments beyond mere crash tests. The underlying premise is logical: vehicles that are easier to control are less likely to end up in critical situations. Euro NCAP started awarding points for ESP systems in 2009; just two years later, ESP systems were legally required in all new cars. Now NCAP officials publish roadmaps indicating which safety criteria they will be evaluating in the future. By publishing these roadmaps far in advance, they give auto manufacturers and suppliers plenty of time to respond.
And the scope continues to grow. In addition to vehicle occupants, NCAP testers are paying increasing attention to more vulnerable road users such as pedestrians and cyclists. Today, Euro NCAP safety ratings cover four main a reas: adult protection, child protection, pedestrian protection and safety assist technologies. “This will give further impetus to the development of driver assistance systems, especially predictive systems,” explains Thomas Herpich. As ZF’s Senior Manager Legislation and Regulatory Affairs & System Engineering V & V, he is permanently engaged in dialog with lawmakers and the rating agencies.
For years, the company has stayed in regular contact with consumer protection organizations and the relevant legislative bodies. Intelligently designed safety systems help improve road safety around the world. Consequently, engineers actually welcome the associated challenges. “It’s our job to make vehicles safer. We’re constantly having to ask ourselves new questions and find the right technical solutions. Our systems save lives,” says Herpich.
And there’s still plenty to do, especially in view of foreseeable developments in automated driving. Here, the big challenge surrounds the moment in which control of the vehicle is handed back to the driver – the moment when the system signals to the driver, “it’s time for you to take over again!” The usual visual or optical signals might not be enough for a safe transfer of command. “So in this case, the driver’s seatbelt could tighten slightly, to attract his or her attention,” says Herpich, as he describes one possible solution. In this scenario, the traditional seatbelt – originally developed as a passive safety feature – acquires an additional communication function that transforms it into an active safety device. An evolutionary step the original developers of the seatbelt could never have imagined.
Front-seat passengers are also receiving more attention. ZF is developing special airbags for drivers and their front-seat companions that have very little in common with simple “bags of air.” For the above-mentioned Oblique Moving Deformable Barrier (OMDB) crash test, ZF engineers developed a system of front and curtain airbags with special V-shaped and U-shaped chambers. “The special geometry covers the area around the A-pillar and instrument panel, preventing heads from hitting these components,” says Dirk Schultz. “And front-seat passengers are protected from extreme movements forward and left by our ‘parallel cell front seat passenger airbag’, which widens out toward the center of the vehicle. Both airbag systems are also designed to cushion the rolling motion of the head when it impacts,” adds Schultz, Vice President Global Engineering Airbags & Inflators at ZF.
But with autonomous driving on the horizon, engineers must think even further ahead. Whereas today’s vehicle occupants – especially drivers – sit in clearly defined positions at a certain distance from steering wheel and pedals, the variable design of future vehicle interiors means that in certain situations, drivers will move away from this “ideal” (i.e. predictable) position. If, in such a situation, a crash should happen, today’s airbag systems may no longer provide sufficient protection. To fully protect vehicle occupants in a wide variety of alternative situations, new or modified safety systems may be required. This is yet another very good reason for making efforts to further improve passive safety systems – and also introduce active safety systems that help prevent accidents from happening in the first place.
Whereas the safety standards in industrialized countries are continuously improving, many emerging nations are only just starting to establish basic safety standards. India is planning to become the world’s third-largest automotive market by 2020. And yet according to WHO statistics, more than 200,000 traffic fatalities occur in the country every year. Vehicle occupants account for up to 20 percent of these deaths. The major factor here is the relative scarcity of airbags or robust vehicle structures. Now Bharat NCAP, founded in 2011, is on the case. January 2015 saw the introduction of legislation governing head-on and side-impact collisions. The second stage involves the implementation of an NCAP test protocol.
So what’s happening in China? “The Chinese version of NCAP won’t simply follow European or U.S. standards. It will set its own priorities for the future by focusing on passive safety, pedestrian safety, active safety – including automatic emergency braking – and fuel efficiency, not to mention overvoltage protection in hybrid and all-electric e-vehicles,” says Chris Wu, Engineering Director Occupant Safety Systems at ZF China. In contrast to India and China, sophisticated safety technology has already reached the economy segment in Europe. The new Ford Fiesta, for example, contains 15 advanced driver-assist systems – features that just a few years ago were only found in luxury cars.
ZF has specific expertise in the development of intelligent safety systems