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Robotaxis Are Cool but Are Not Yet Safe

shallow focus photography of Taxi signage
Photo by Lexi Anderson. The BFD.

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Karl D. Stephan

Karl D. Stephan is a professor of electrical engineering at Texas State University in San Marcos, Texas. This article has been republished, with permission, from his blog Engineering Ethics, which is a MercatorNet partner site. His ebook Ethical and Otherwise: Engineering in the Headlines is available in Kindle format and also in the iTunes store.

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General Motors’ autonomous-vehicle operation is called Cruise, and just last August, it received permission (along with Google’s Waymo) to operate driverless robotaxis in San Francisco at all hours of the day and night. This made the city the only one in the United States with two competing firms providing such services.

Only a week after the California Public Utilities Commission acted to allow 24-hour services, a Cruise robotaxi carrying a passenger was involved in a collision with a fire truck on an emergency call. The oncoming fire truck had moved into the robotaxi’s lane at an intersection surrounded by tall buildings and controlled by a traffic light, which had turned green for the robotaxi.

Engineers for Cruise said that the robotaxi identified the emergency vehicle’s siren as soon as it rose above the ambient noise level, but couldn’t track its path until it came into view, by which time it was too late for the robotaxi to avoid hitting it. The passenger was taken to a hospital but was not seriously injured.

As a result, Cruise agreed with the Department of Motor Vehicles to reduce their active fleet of robotaxis by 50 percent until the investigation by DMV of this and other incidents was resolved.

Near-tragedy

In many engineering failures, warning signs of a comparatively minor nature appear before the major catastrophe, which usually attracts attention by loss of life, injuries, or significant property damage. These minor signs are valuable indicators to those who wish to prevent the major tragedies from occurring, but they are not always heeded effectively. The Cruise collision with a fire truck proved to be one such case.

On 2 October, a pedestrian was hit by a conventional human-piloted car on a busy San Francisco street. This happens from time to time, but the difference in this case was that the impact sent the pedestrian toward a Cruise robotaxi. When the unfortunate pedestrian hit the robotaxi, the vehicle’s system interpreted the collision as “lateral”, meaning something hit it from the side. In the case of lateral collisions, the robotaxi is programmed to stop and then pull off the road to keep from obstructing traffic.

What the system didn’t take into account was that the pedestrian was still stuck under one of the robotaxi’s wheels, and when it pulled about six meters (20 feet) to the curb, it dragged the pedestrian with it, causing critical injuries.

California regulators reacted swiftly. The DMV revoked Cruise’s license, and the firm announced it was going to suspend driverless operations nationwide, including a few vehicles in Austin, Texas, and other locations. There were only 950 vehicles in the entire US fleet, so the operation is clearly in its early stages.

But now, after Cruise has done software recalls for human-piloted vehicles as well as driverless ones, it is far from clear what their path is back to viability. According to an AP report, GM had big hopes for substantial revenue from Cruise operations, expecting on the order of $1 billion in 2025 after making only about a tenth of that in 2022. And profitability, which would require recouping the billions GM already invested in the technology, is even farther in the future than it was before the problems in San Francisco.

Human vs machine

The consequences of these events can be summarised under the headings of good news and bad news.

The good news: nobody got killed, although being dragged twenty feet under the wheel of a robot car that clearly has no idea what is going on might be a fate worse than death to some people. After failing to heed the warning incident in August, Cruise has finally decided to react vigorously with significant and costly moves. According to AP, it is adding a chief safety officer and asking a third-party engineering firm to find the technical cause of the 2 October crash. So after clearly inadequate responses to the earlier incidents, a major one has motivated Cruise management to act.

The bad news: several people were injured, at least one critically, before Cruise realised that, at least in the complex environs of San Francisco, their robotaxis posed an unacceptable risk to pedestrians. I’m sure Google’s Waymo vehicles have a less-than-perfect safety record, but whatever start-up glitches they suffered are well in the past. Cruise does not have the luxury of experience that Waymo has, and is in a sense operating in foreign territory. Maybe Detroit would have been a better choice than San Francisco for a test market, but that would have neglected the cool factor, which is after all what is driving the robotaxi project in the first place.

Back when every elevator had a human operator, there was a valid economic and engineering argument to replace the manually controlled units with automatic ones. The main reason was to eliminate the salary of the operator. Fortunately, the environment of an elevator is exceedingly well defined, and the relay-based technology of the 1920s sufficed to produce automatic elevators that met all safety requirements and were easy enough for the average passenger to operate.

Nevertheless, some places clung to manual elevators as recently as the 1980s, as I recall from a visit to a tax consultant in Northampton, Massachusetts, whose office was accessed by means of an elevator controlled not by buttons, but by a rather seedy-looking old man.

Being an old man myself now, I come to the defence of everyone on the street who would like to confront real people behind the wheel, not some anonymous software that may — may! — figure out I’m a human being and not a tall piece of plastic wrap blowing in the wind, in time to stop before it hits me. Yes, robotaxis are cool. Yes, they save on taxi-driver salaries, but this ignores the fact that one of the few entry-level jobs that recent immigrants to this country can get which actually pays a living wage is that of taxi driver, many of whom are independent entrepreneurs.

Robotaxis may be cool, but dangerous they should not be. GM may patch up their Cruise operation and get it going again, but then again, it may go the way of the Segway. Time will tell.

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