They also programmed the car to do things like nudge a little into the oncoming lane (when safe) to get around things like double-parked trucks.
Another interesting example is the stop sign. The code requires a full stop. So many people instead do a rolling stop it's called the "California stop" in that state. Usually it results in no ticket unless police have gotten bored and set up a stakeout.
But does a robocar need to always do a full stop? It knows the full geometry of the intersection and where its sensors can see and not see. It can know if it has a full picture of the situation and that indeed there is nobody else within a modest distance of the stop signs, and no pedestrians about to cross the crosswalks in question. In that situation, why not let the car roll through? Unlike a human, the car would only do this when safe.
Another situation is "no left turn" or "no turn on red" intersections. We restrict human drivers because they can't be trusted. Each "no turn on red" has a reason behind it, and that particular reason can be programmed into the car. For example, there are "no turn on red" and "no left turn" or "left turn on arrow only" locations which are signed this way because too many people will try to take the turn and end up impeding fast traffic. But a robocar that is certain it won't do this should make the turn when clear and improve the flow of traffic. These signs tend to be in force all the time, not just when there is heavy traffic and they are truly needed. Off peak, there is no reason not to allow these turns when safe and clear.
Even those who would advocate the cars be speed-limited might think twice when considering the subject of testing. To be safe, robocars must be extensively tested in real world driving conditions, and in the United States, that involves speeding. A car constrained to the speed limit could be tested in only a small subset of real driving situations. While it could be argued that if it never will speed when operating, it does not need to handle such situations, the reality is that speed-limited testing will not adequately test conditions other than driving in the right lane, being passed by most traffic. Keeping strictly to the rules (such as slower traffic keep right), the car will not be able to test extensively situations only found in middle or left lanes, including being passed on the right by speed demons and several other complex flows of traffic. These flows do occur for lower speed cars but less frequently, and still need testing.
This presents another conundrum for the companies doing the testing, which will think twice about the vicarious liability issues of instructing their test drivers to exceed the speed limit, but for safety there can be no other choice.
Going way beyond the law
The current vehicle code is complex but effectively expresses just two principles for moving vehicles:
- Be safe.
- Do not unfairly impede the flow of traffic.
Most of the regulations are written to help human drivers obey these principles, because they can't be trusted on their own. Vehicles that can be trusted might be better with an entirely different, much simpler vehicle code. All robocars with the same software will drive similarly, and there will only be a modest number of different software providers in the market.
If a vehicle makes a mistake and violates the code or the principles in a way that the maker will face punishment, the software will be modified and all vehicles will never make that mistake again. This is vastly different from how humans act. If a human makes a mistake, that means it’s more likely that other people will make the same mistake, and the law gets amended to forbid it.
Once robocars can be certified safe, they may well be able to drive even faster than humans can safely drive. While this is not energy efficient, in many ways it might make sense. This could either be done autobahn style, where the left lane has no speed limit and slower cars must pull to the right, or it could involve managed lanes that are limited to high speed robocars at certain times of the day. This would strongly encourage a switch to robocars.
If efficiency is the issue, one could also imagine high-speed lane use being granted only to carpools, vanpools and other non-solo transport. In today's carpool system, it is hoped that people will do the hard work and suffer the inconvenience of arranging carpools so they can use a lane with less congestion than the main lanes. Only a very few people do this—only a small fraction of the carpools are "induced" carpools; the rest are couples or people already carpooling.
In the robocar world, where your solo car can drop you off to join an ad-hoc carpool and pick you up on the way back, and where a short-range robotaxi can pick you up from where your ad-hoc carpool members part ways, real carpooling becomes far less inconvenient. Given an added incentive like a 100-mph dedicated lane for the bulk of the trip would be quite attractive and save energy to boot.
Even without a dedicated lane, a legal speed limit of 85mph or 90mph in the left lane for robo-carpools could make such travel very attractive, particularly if there is enforcement of a German style rule of leaving the left lane if somebody comes up behind you at a faster speed if safe to do so.
A special driver's license for the car?
The idea of having a less restrictive vehicle code for the robocar is a challenging one, legally. It will only come after a lot of history. Curiously, the current legal regimes may offer a way to do it faster. The Nevada law, for example, declares that while the vehicle code regularly refers to things the "driver" should do, a self-driving car will be treated as though the "driver" is the person who activated the system. At first that will be the person sitting behind, but not holding the wheel.
The Nevada law also has a special license endorsement. The initial goal of this endorsement was to make sure people who operated the cars were trained in how to operate them. Over time, this becomes less important as the cars will do all the work and in fact we want to allow the disabled to use them.
Initially this endorsement could offer an interesting legal approach. Create a new class of license. This license is valid only when operating an appropriately certified robocar. With this class of license, certain vehicle code restrictions (like speed limits) could be different than they are for people with the general license. This has precedent, though mostly classes of licenses allow you to do things like operate bigger vehicles, or carry passengers for money etc. Why not one that gives you a different speed limit?
This is not a perfect situation. The truth is it's the car which would prove its ability to safely follow a different code, not the person. But our system of laws is much more tied to people than machines, for good reason.