Volvo estimates that a person has a one in 54 million chance of causing an car accident.
"People make few mistakes while driving, relatively speaking," said Mikael Ljung Aust, who is Volvo's expert in crash avoidance. "Therefore, it's hard to educate people to perform better."
Volvo, however, says a recent assessment of data from drivers who allowed cameras to monitor them while on the road showed the risk of an accident is very high when two unrelated events happen simultaneously.
"If you happen to look away at the same time that something unexpected happens, such as the car ahead of you braking hard, you have little time to recover," said Aust, who is a cognitive scientist by training. He said more than half of all crashes occur when those two events happen at the same time.
Fortunately, Volvo also has found a reliable way to prevent this dangerous combination from becoming a front-to-rear collision. It does so by appealing to more than one sense simultaneously.
That is the reason Volvo's City Safety crash prevention system provides a sound warning and a brake pulse at the same time. Aust said that combining sound with a haptic component improves human reaction time by 250 milliseconds compared with other warnings that don't appeal to our sense of touch.
Volvo's Magdalena Lindman, who is an expert in traffic safety data analysis, says that City Safety helps reduce rear-to-front crashes by 45 percent compared with vehicles without it.
The crucial component, however, is the timing of the action.
“It's easy to get a car to brake. The key is to make sure it doesn't brake unless it is absolutely necessary," said Thomas Broberg, Volvo's director of safety strategy and requirements.
The automaker believes that City Safety provides the driver with the right amount of warning at a time when it's still possible to access the situation and decide what to do before the car takes action.
Volvo's forthcoming XC40 premium compact SUV will have the fourth generation of City Safety, which has been upgraded multiple times since its debut in 2006 and now can prevent collisions with pedestrians and animals as well as vehicles. That is just one of the reasons why Broberg said: "The XC40 will be one of the safest vehicles in its segment. We don't accept that you could end up in a situation where you might have a crash that results in injury or death."