Imagine streets and highways full of self-driving, a.k.a., autonomous, vehicles loaded with the latest information, navigation and crash-avoidance technology.
Should make that next drive to the grocery store as safe as you possibly could imagine, right?
Well, not necessarily, according to two researchers at the University of Michigan Transportation Research Institute (UMTRI), which advocates safer, more sustainable vehicles.
“It is not a foregone conclusion that a self-driving vehicle would ever perform more safely than an experienced, middle-aged driver,” Michael Sivak and Brandon Schoettle wrote in their recent study, “Road safety with self-driving vehicles: General limitations and road sharing with conventional vehicles.”
“The fatality rate per distance driven using a conventional vehicle is strongly influenced by the age of the driver … with the lowest rates for middle-aged drivers,” the researchers reported in a section that considered the “computational speed, constant vigilance, and lack of distractability of self-driving vehicles versus predictive knowledge of an experienced driver.”
“One of the likely reasons for the minimum being reached for middle-aged drivers is their predictive knowledge about the likely intentions of other road users,” wrote the UMTRI researchers. “This predictive knowledge was acquired through years of driving experience.”
Another major reason why middle-aged drivers may be safer, the study said, is their reduced risk taking.
“Although older drivers possess the most predictive knowledge, the risk function for them is elevated because of the increased frequency of physical and mental limitations,” the researchers wrote.
Fatality rates are significantly higher for younger and older drivers, the UMTRI research indicated.
Autonomous vehicles are the “talk of the town,” according to the study introduction, because of the prospect that they will make traffic safety nearly perfect, increase mobility of people unable to drive, and reduce the environmental footprint compared to human-driven vehicles.
But, according to the study, “the expectation of zero fatalities with self-driving vehicles is not realistic,” and “during the transition period, when conventional and self-driving vehicles would share the road, safety might actually worsen, at least for the conventional vehicles.”
And the transition to self-driving vehicles won’t happen overnight, according to Sivak and Schoettle.
“There will likely be at least a several-decade-long period during which conventional and self-driving vehicles would need to interact. Furthermore, to the extent that some people may want to drive only conventional vehicles, this overlapping period might last indefinitely.”