Simulations suggest that only a few cars need to have the technology to make a significant impact. If 1 percent to 5 percent of cars can send real-time data about their speed to a central hub, traffic jams can be spotted within five minutes, and cars equipped with GPS systems can be offered alternate routes to avoid them.
Adaptive cruise control could also prevent many traffic jams from forming in the first place. Drivers tend to change speed on hills or when approaching tunnels, which can cause traffic to bunch up. They also brake too much in response to vehicles ahead of them. After a few drivers in a lane do this, traffic can come to a halt. Cars with adaptive cruise control keep a steady speed on hills and brake more gradually if cars slow down.
Werner Huber, who heads driver assistance systems development at BMW, estimates that if one in five cars had adaptive cruise control, it would smooth out traffic by interrupting the chain reaction that ties up traffic. If all cars had it, it could increase the capacity of roads by 20 percent and decrease fuel consumption by 83 percent in congested areas, according to a study by researchers in Japan.
The total impact of vehicle automation on fuel consumption is hard to predict. When traffic congestion eases, more people may decide to commute by car or live farther from work, says Tim Lomax, a research engineer at the Texas Transportation Institute.
Ultimately, automakers may find that the technology is the only way to keep driving satisfying. At a recent Mobile World Conference in Barcelona, Bill Ford, chairman of Ford, warned of an impending catastrophe as cities become more congested. He said vehicle automation will be key to cars moving at all, since some predict that the number of vehicles on the road will increase from one billion to four billion. “When we do the math, and when we look at the global vehicle population, there’s cause for real concern if we do nothing,” he said. “That raises the possibility of global gridlock. A never-ending traffic jam that wastes time, energy, and resources.”