The simple action of pulling your safety belt across and clicking it into place has become second nature to us when we get into a car – we probably give more thought to what music to listen to or to putting an address into the sat-nav. But there’s more to this familiar feature than meets the eye. In fact, 2019 marked 60 years since the three-point safety belt became a standard feature on a production car, when Volvo Cars introduced it in their 121 Amazon and PV544 models.
And although today’s cars surround us with high-strength steel cages, numerous airbags, meticulously engineered crumple zones and sophisticated active safety systems, the three-point safety belt remains our first line of defence against the extreme forces in a collision. The fundamental design has yet to be bettered, and no other automotive safety feature has made such a significant contribution towards saving lives, or reducing injuries, over the past six decades. In the words of the United States’ National Highway Traffic Safety Administration: “Buckling up is the single most effective thing you can do to protect yourself in a crash.”
Shaped by aviation
The man behind the modern three-point safety belt was Volvo Cars engineer Nils Bohlin. Bohlin was familiar with the impact moving forces could have on a human body – his previous job was as an aviation engineer involved in developing ejector seats. On joining Volvo Cars in 1958, he was charged with improving safety on the road rather than in the air, and refining the design of the safety belt was his first task.
Various two- and three-point safety belts had been developed by other manufacturers at this point – and Volvo Cars had already fitted two-point belts to some of its cars – but Bohlin saw that the technology could be improved. He focused on designing a belt that would provide better restraint, while making contact with the strongest parts of the body – the chest and the pelvis. “I realised that both the upper torso and the lower part of the body had to be held securely in place, with one belt across the chest and another across the hips,” Bohlin said at the time.
And, since wearing a safety belt was not compulsory at the time, he also focused on making the belt as easy as possible to put on and adjust, so that people would be more likely to wear it. “It was a matter of finding a simple solution,” he said. “It does not matter how effective a restraint is if it’s not used.”
A gift to the world
Bohlin’s eventual design has been so successful that it has, in essence, barely changed since. Lotta Jakobsson, Senior Technical Leader, Injury Prevention, at Volvo Cars Safety Centre, says: “Nobody has managed to replace the safety belt. It remains the most important safety system in a car. And the unique thing about it compared with other safety features is that it provides protection in every type of crash. It’s fundamental to safety.”
For his contribution to improving global road safety, Nils Bohlin was inducted into the Hall of Fame for Safety and Health in 1989 and, in 2002, the National Inventors Hall of Fame. Bohlin’s innovation was so significant not just because of the effectiveness of his design, but also because of Volvo Cars’ decision to leave the patent for it open, so that every vehicle manufacturer could benefit from the technology.
“Bohlin perfected the geometry of the three-point safety belt and the design of the sliding buckle,” says Lotta. “That’s what we gave away. And that has helped make the world a bit safer for everyone, in line with Volvo Cars’ human-centric approach.”
Estimates vary, but figures suggest that since 1959 the three-point safety belt has saved over a million lives and reduced the severity of injuries caused by collisions for millions more. Michiel van Ratingen, secretary general of Euro NCAP, the vehicle safety testing organisation, says: “The three-point seatbelt remains the number one safety technology in the world. Wherever you go, standard fitment of seatbelts and the introduction of seatbelt legislation has coincided with significant and marked decreases in driver and passenger fatality and injury rates. Moreover, the invention of three-point seatbelts has made many other safety innovations possible, from airbags to child restraint systems, that car users can benefit from every day.”
“The three-point safety belt remains the
number one safety technology in the world”
MICHIEL VAN RATINGEN, SECRETARY GENERAL, EURO NCAP
Although the strap and buckle you handle every time you get in a car haven’t changed much over the years, safety belt technology itself has been in a state of incremental evolution. Volvo Cars continues to be at the forefront of these developments, which have been the result of advances in technology and informed by the insight gained from the company’s unique focus on real-life collisions.
The first big breakthrough came in 1969, with the introduction of inertia reel retractors that help to reduce slack in the belt, while also providing better comfort. Front safety belt reminders were added in 1971, with three-point rear safety belts introduced a year later.
Pre-tensioners, which activate if a crash is unavoidable and pull the safety belt tight even if the seat occupant is wearing bulky clothes, have been another key area of improvement. Volvo Cars introduced its first example in 1987, and continued to refine the technology to the point where they have been available in every seat row in a Volvo car since. Force limiters that reduce the risk of upper body injuries made their debut in 1996. A range of advances were made during the 2000s, including safety belt reminders for all seats and pre-tensioners that activate in the event of a rollover accident help to keep occupants in place.
Today, most new Volvo cars are available with electrically retractable front safety belts. These tighten if the car senses that an accident is likely, ensuring that occupants are in the best possible position. Because this function is reversible, it can be activated earlier and more often than a conventional pre-tensioner. If an accident doesn’t happen, the belt tension returns to normal – in the event of an accident, the two technologies work together to give the best possible protection. As well as anticipating front and rear collisions, the electrically retractable belts are activated if the system detects the car has left the road. This, in combination with a unique seat structure, is a world-first function that helps to reduce injuries in what is one of the most common types of accident.
A new era of travel
As we look forward to an exciting future where autonomous cars have the potential to make roads even safer, where does the safety belt fit in? The Volvo 360c concept car – unveiled in 2018 – offers one possible suggestion. Envisioned as an alternative to first-class air travel, the 360c is a fully autonomous concept that offers the possibility of relaxing, working or even sleeping on board. Volvo Cars’ safety engineers looked at how different passenger positioning could influence safety and, when it comes to sleeping in the car, developed the prototype for a special safety blanket that performs the same function as a safety belt.
“It monitors where you are and adapts accordingly, to make sure that it makes contact with the strongest parts of the body,” says Lotta Jakobsson. “It’s based on the principles of Nils Bohlin, but adapted to people lying down while travelling.”
For now the 360c is a ‘conversation starter’, designed to spark debate about how cars might evolve over the coming years. It doesn’t provide all the answers, but one thing we can be sure of is that safety will be at the core of everything Volvo Cars does, whatever the future holds. Even as it enters its seventh decade, the safety belt – in some form or another – will continue to be one of the most important features in our cars.
Safer by design:
Four things you didn’t know about the safety belt
• Safety organisations around the world estimate that wearing a safety belt in the front seats of a car reduces your chance of fatal injury by approximately 50 per cent
• The German patent office named the three-point safety belt as one of the eight patents to have the greatest significance for humanity between 1885 and 1985
• Safety belts save the lives of approximately 15,000 people in the USA per year, according to figures published by the National Highway Traffic Safety Administration
• Volvo Cars introduced its distinctive ‘since 1959’ safety belt logo with the XC90 in 2014. It now features on every 90 Series model
Editorial collaboration credit: LEO WILKINSON / Volvo Canada
Edits: Kate Shelton
IMAGE CREDIT: Volvo Canada