Vast sums of money are being devoted to developing self-driving cars. To date, licensing requirements require that self-driving cars have a licensed human driver at the wheel able to take over from the machine — thus negating most of the potential value of the technology. Technical progress has been rapid, with cars increasingly able to drive themselves at night and in bad weather (0). It is therefore now time for policymakers to identify the criteria under which they would allow self-driving cars without humans at the wheel.
Policymakers should start by adapting the process we use for human drivers. We should have road tests for robot cars. We should put the self-driving car on the street, give it a moderately challenging course to drive under realistic conditions, and confirm that it does as well as a medium-skilled human. As with today’s driver exams, there should be a human inspector in the vehicle ready to take over if the car behaves dangerously — and if the human needs to take over, the test fails. If the car passes the test, that model should be licensed for self-operation. And just as with humans, we should revoke that license if the self-driving car model gets into too many accidents.
We can make the road tests for autonomous vehicles as stringent as desired. Rather than merely navigating a simple course, the vehicle might be tested on its ability to operate in weather and darkness, navigate an unexpected construction site, pull over for an emergency vehicle, avoid children that dart out into traffic, and so forth. (Obviously, there may be some cost in developing a suitable test that does not require using actual children.) We should also confirm that damaged vehicles “know they are damaged” and do not continue to operate autonomously if it has become unsafe to do so.
Unlike human licenses, we should not expect or encourage the states to honor one another’s certifications. Nor should we press for a uniform national standard. A self-driving car in New York City faces a much more challenging environment than one in Wyoming and ought to be held to higher standards. California might need to test cars in hill and mountain conditions that would be irrelevant in Kansas. However, licensing need not be done separately by every state. The states routinely form compacts and agreements around driver licensing, and it would be easy, say, for New York and New Jersey to arrange to cross-honor one another’s licensing.
Humans are all unique; automobiles and computer programs are not. We should license models, not individuals, and likewise should keep accident statistics per model. Like crash-test results, the results of the licensing test ought to be publicized. And just as the FAA can ground an airliner model if a defect is discovered, we should be prepared to revoke self-driving permission from a model of vehicle if serious flaws emerge. The vehicles should be designed in such a way to facilitate remote enforcement of these rules.
Driver licenses for humans can come with restrictions. For instance, some people are only licensed to drive while wearing corrective lenses. Some states forbid young drivers from driving late at night or with passengers; drivers under 18 are prohibited in New York City (1). States should consider doing the same for self-driving vehicles: We might restrict them to daylight, good weather, lower speeds, and so forth.
We have been licensing drivers for a long time — the first statewide licensing requirement dates back to 1913. The states have considerable experience administering such systems. We should rely on this wealth of knowledge as we start allowing self-driving vehicles: Whenever possible, we should evaluate robot drivers the way we do humans.
Conflict of interest disclosure: The author has a bet with his wife concerning autonomous vehicles. The author wins if by December 31, 2022, it is legal, on a majority of days, for a majority of commuters who live and work in one of the country’s top-10 metro areas to make their door-to-door commutes at their usual times in vehicles with no drivers. The loser of the bet is obligated to take the winner out to a nice dinner “by the most technically sophisticated means available.”