Special Licenses Would Stall the Ascent of Self-Driving Cars

By Hilary Rowen, Sedgwick San Francisco

I will be a guinea pig. Shortly, I will be sitting in a simulator at the Stanford University Center for Design Research generating data on how ordinary drivers respond when required to take control of a self-driving car.

Most of us are fairly good at keeping our attention on the road while we are actively driving. (Although when our attention strays, the chance of being in an accident increases.) As cars increasingly drive themselves, drivers will be able to take their eyes off the road, but will need to retake control of the vehicle on occasion. Most of us are likely to find these rare occasions somewhat challenging.

As self-driving cars move closer to “deployment” – i.e., sales to the general public – the question has arisen whether a special license, by analogy to separate license requirements for motorcycles or trucks, should be required for the operator of a self-driving car.

Classifying Self-Driving Cars

First, we need to take a short detour into the classification of self-driving cars. Two systems for classifying the level of autonomous driving functions are in current use. In 2013, the National Highway Transportation and Safety Administration issued a four-level classification system; in the same year, SAE International, a professional organization of automotive and aerospace engineers, issued a five-level system.

The NHTSA and SAE classification systems are quite similar. Level 1 in both the NHTSA and SAE classifications refers to stand-alone driver assistance features, such as automatic braking. Both the NHTSA and SAE systems also include a Level Zero, where there is no automation. Level 2 in both systems refers to partial automation. The vehicle performs significant vehicle control functions, such as distance maintenance and lane maintenance. Level 2 cars can be operated in “hands free” and “foot free” mode, at least in some driving environments, but require that the driver remain alert and actively monitor the driving environment. A wide range of cars that qualify as Level 2 will be on the market in the couple of years.

Under both the NHTSA and SAE classifications, Level 3 cars delegate all driving functions to the vehicle. Level 3 car retain steering wheels and brake pedals, and will signal the driver when driving conditions require the driver to retake control. An alert could sound because of a change in driving conditions – such as heavy rain – that reduced the quality of the sensor data below the level required for autonomous operation or because the vehicle entered a geographic area where autonomous operation was not authorized.

A number of manufacturers and technology company – most notably Google – are testing prototypes of Level 3 cars. There are various estimates regarding when Level 3 cars will be on the market; it is likely that a number of auto manufacturers will offer Level 3 cars within a decade.

NHTSA has a single classification, Level 4, for vehicles that dispense with operator controls for steering and braking. SAE bifurcates this category into two subsets: SAE Level 4 vehicles cannot operate in all conditions and all geographic locations. Prototype SAE Level 4 cars are currently being tested. It is quite possible that some Level 4 autonomous vehicles will be deployed on a limited basis within the next five years. Such deployment will likely involve low maximum speeds (in the range of 25 to 35 miles an hour) and very limited geographic travel zones. Due to these limitations, the initial deployment of Level 4 cars is likely to be as people-mover fleet vehicles.

SAE Level 5 can operate anywhere, any time; including driving situations that would be challenging to a human driver. SAE Level 5 vehicles are still in the speculative vision stage. The sheer versatility of a human driver is hard to match, even though the current technology can easily exceed our reaction time and does not have blind spots and other deficiencies of human drivers.

Special Licenses for Level 3?

Level 3 vehicles offered for sale to the public will have a lower incidence of accidents – and quite likely will produce less severe bodily injuries in the event of an accident – compared with conventional cars. The relative incidence of accidents in Level 2 and Level 3 cars is more difficult to predict, but it is likely that less competent drivers will pose a lower aggregate risk in Level 3 cars.

Nevertheless, Level 3 vehicles pose particular challenges to drivers in the event of a transition from autonomous to driver-controlled operation. Under the NHTSA definition, Level 3 cars will be required to provide the driver “with an appropriate amount of transition time to safely regain manual control.” Even with alerts, some drivers will fail to take control timely and cause accidents. With Level 3 cars, there will be some high risk miles, even though Level 3 cars on average will generate fewer accidents per mile traveled.

The ability to respond quickly when the mind is engaged in an activity unrelated to driving – texting, reading, talking on the phone, watching a movie – will affect a given driver’s chance of being involved in an accident when signaled to re-take control of a Level 3 car. The existence of high risk miles and the varying ability of drivers to respond has led to suggestions that operators of Level 3 cars be required to hold a separate driver’s license.

This would be a bad idea. As a matter of public policy, higher risk drivers should not be deterred from purchasing and operating autonomous vehicles. The people who are likely to have the poorest response times (and worst judgment) when faced with the sudden need to take control of a Level 3 car are also likely to pose the highest risk when behind the wheel of a conventional car. From a public safety perspective, we want teenagers, the very elderly, and people who simply are not very competent drivers – but hold driver licenses – to be in Level 3 vehicles.

Imposing special drivers’ license requirements for Level 3 cars – similar to the separate license required to operate a motorcycle – will inhibit the introduction of Level 3 cars. Less competent drivers might not pass a separate autonomous vehicle test; but would continue to drive. Many drivers who could easily pass an autonomous vehicle driving test would be deterred from buying a Level 3 car by the need to get a new license. As a result, the potential for accident reduction offered by Level 3 cars would not materialize.

The hypothetical autonomous vehicle driving test might be very similar to sitting in the simulator at Stanford. Hopefully, this experience will not become a prerequisite for Level 3 car purchasers.

This article was originally published in the Daily Journal on July 19, 2015.