Federal Safety Agency Investigates Tesla Autopilot

 

In 2015, the upstart automaker Tesla introduced its Autopilot feature, an advanced artificial-intelligence-enabled system that takes over most of the routine operations that a human driver normally performs.  At the same time, Tesla warned Autopilot users that they should remain attentive with their hands on the wheel at all times, even when Autopilot is engaged.

 

This is a little bit like taking a hungry child into a candy store and telling them not to touch anything.  Most kids will obey, but it's hard on the kid and it can lead to embarrassing situations.

 

It's not surprising that, according to the U. S. National Highway Traffic Safety Administration (NHTSA), since 2016 ten people have died in eight crashes of Tesla vehicles in which the Autopilot feature was the cause of the crash.  Lately, there have been numerous crashes, one of them fatal, in which Teslas with Autopilot engaged have run into the rear of emergency vehicles with flashing lights. 

 

Finally, the NHTSA has had enough.  It has launched a formal investigation into how the Autopilot system works, how it is implemented, what its defects are, and what steps Tesla has taken to make sure that drivers are paying attention like they are supposed to when the Autopilot is driving the car.  There is abundant evidence that in many of the crashes, the driver was doing something other than watching the road:  watching a movie, playing a video game, or even sitting in a seat other than the driver's seat.  The Autopilot system is supposed to monitor hand pressure on the steering wheel, but according to some sources, this feature is very easy to defeat, and many people appear to have done so.  And most of them probably get away with it most of the time.  But not always.

 

In human-machine safety issues, there is a tradeoff between the two poles which represent extreme approaches to operating a device safely.  One pole relies totally on training the individual not to do dangerous things, or to do them in a safe way, if that makes sense.  Think of stunt drivers in the movie business:  they do things with cars that cars are not designed to do, but with careful planning and finely-honed skills, they manage to survive car flips, crashes, and other tricks that have probably passed into history now that CGI technology is so good that real stunt drivers are probably looking for work.  But the point is that this approach to safety concentrates on the knowledge and attention of the operator or driver, and basically tells him or her to drive safely.

 

The other pole of safety is building in foolproof safety features to the machine itself, so that even an ignorant five-year-old turned loose with the keys couldn't get hurt.  It's not possible to make a car at a reasonable price that is completely safe no matter what you do—at least not yet.  But many of the autonomous-vehicle-type features that are now showing up on many makes besides Tesla move in this direction:  lane-keeping features, automatic braking to avoid head-on collisions, and so on.  They make up for a driver's deficiencies, inattention, or errors.  But they are far from perfect yet, and so the attention and intelligence of the driver are still needed to fill in the gaps where systems like Tesla's Autopilot still can't figure out the situation, such as an emergency vehicle stopped in your lane.

 

I expect the NHTSA will encounter some headwinds in trying to figure out Tesla's Autopilot system.  Elon Musk has, shall we say, a rather cavalier attitude toward convention and traditional ways of doing things, and recently abolished Tesla's public-relations department.  Perhaps he thinks a few tweets from him do just as well, and in the absence of more formal ways of getting information from the company, he may be right.  But nobody can stop the NHTSA from renting or buying some Teslas and putting them through various scenarios and seeing what they do with and without human supervision.  Whatever is going on under the hood, the results will be clear to see.

 

But just testing the hardware and software is only part of the issue.  The poisonous mixture that the NHTSA is dealing with combines an Autopilot system that is very good—so good that people really can let it drive the car for many minutes at a time and get away with it—and drivers who either intentionally put too much trust in the Autopilot system, or simply get distracted and fail to do what they know they ought to be doing, which is looking at the road.  But nobody just accidentally starts watching a movie or playing a video game, and so we must conclude that in at least some of the cases where inattention and the Autopilot have caused crashes, people simply ignored the advice of Tesla to not let Autopilot drive the car by itself, and paid the penalty for their inattention.

 

Now in some countries and cultures (and political persuasions—notably extreme libertarianism), this would not be a concern of the government's.  If people want to do foolish things and ignore instructions, well, let them do it and suffer the consequences.  The problem with this attitude is that it ignores everybody else, particularly other people who might be harmed and killed in the same accident.

 

My point is simply that we in the U. S. have grown accustomed to holding automakers to safety standards that avoid preventable accidents, in the sense that preventable accidents follow a consistent pattern which reasonable interventions at not too much cost can prevent. 

 

We are in a curious transition phase in which systems like Autopilot are good enough to fool us that they can really drive our cars without us paying any attention, but not good enough to do it for real.  And until it is just as safe to play pinochle from the driver's seat as it is at home, we need some way to remind drivers that they can't ignore the road even if the car seems to be driving itself.

 

Sources:  I consulted an article in Consumer Reports at https://www.consumerreports.org/autonomous-driving/nhtsa-safety-defect-investigation-tesla-autopilot-crashes-a6996819019/ and an article in the Aug. 16 Austin American-Statesman online edition "Feds Open Investigation Into Tesla's Autopilot System.  The statistic on total fatalities and accidents due to Autopilot since 2016 was obtained from https://thehill.com/changing-america/sustainability/infrastructure/561717-increasing-number-of-crashes-involving-teslas#:~:text=In%20total%2C%20at%20least%2010,each%20year%20in%20the%20U.S.

Unanswered Questions About the FIU Bridge Collapse

Last March 15, an innovatively-designed pedestrian bridge installed for less than a week suddenly collapsed onto a busy roadway in Florida International University, killing six people and injuring several more.  Although many bridges have been erected successfully using the technique known as accelerated bridge construction used for this bridge, this was one of the first times such a bridge failed during construction, and so both the engineering community as well as the public at large would like to know what went wrong.  But answers have been slow in coming.

Accident investigations are tedious, painstaking tasks, and it’s understandable that the U. S. National Transportation Safety Board (NTSB), which is the primary agency charged with the investigation, is going to take as long as it takes to find out what happened.  On May 23, the NTSB released a preliminary report on the accident.  But those hoping to read about a metaphorical smoking gun in the report will be disappointed.

This is not unusual for preliminary reports.  Depending on how accessible the raw data is that has to be examined, preliminary NTSB reports can come close to answering all the relevant questions.  But a bridge is a large physical object that doesn’t yield its secrets easily, and it’s quite possible that the agency is conducting tedious and lengthy examinations of the pieces recovered from certain sections of the bridge to reconstruct exactly what happened.

The bridge was a concrete truss, and I learned just now the technical definition of a truss, which “consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object.”  (That’s from Wikipedia.)  Trusses are everywhere in constructed objects.  Your house or apartment probably has roof trusses in it.  If a sign support arching over a highway isn’t a single large tube or pole, it’s probably a truss.  You can tell a truss by its triangles, each side of which is one of the aforementioned two-force members.  And all that means is that the force on each member (strut) is applied at only two points, generally the ends.

The NTSB report focuses on two particular truss members of the bridge, especially one designated as No. 11.  If you picture the bridge as a concrete floor and ceiling connected by slanting concrete beams (truss members), these two members were near each end, slanting downward from near the end of the ceiling to the far edge of the floor at the end of the bridge.  Each slanting member formed the diagonal of a triangle, the other two sides being the end part of the ceiling and a vertical beam connecting the ceiling and floor at each end. 

Clear?  Maybe not.  Anyway, the point of making all these triangles in trusses is that a triangular shape made of straight sides does not change its shape easily.  You can push on the opposite sides of a square made of four bars tied together with pivots at the corners, and the pivots will let you squash the square flat.  But even if a triangle is made with pivots at the corners, it won’t change its shape until one of the sides actually bends or breaks.  And that may be what happened to the FIU bridge.

There has been much attention paid to some cracks that showed up near the bottom of No. 11 several weeks before the collapse.  Photos of these cracks were accidentally released, the NTSB griped about it, and then the agency included them in their report later.  There are good reasons why certain touchy information about accidents shouldn’t be released before an NTSB report is completed, but it’s not clear if these reasons apply in this case.  The Miami Herald commented in an article on the report that the newspaper is trying to get more information about the bridge released from the Florida Department of Transportation under Florida’s public-records act, but the lawsuit is still in progress.

As many people know, concrete can withstand a lot of compression (squeezing), but hardly any tension.  That is why steel reinforcement bars (rebars) are embedded in concrete structures of any size, and why the FIU bridge included adjustable tensioning rods in some of its members, including No. 11.  A couple of sources indicate that construction crews were re-tensioning these rods after it was moved in place when the bridge collapsed.  The Herald report speculates that the member might have been compressed too much by these tensioning rods in an attempt to close the suspicious cracks.  Every concrete structure has a limit as to how much compression it can stand.  If the worker got carried away and put too much stress on an already compromised member, it might have simply crumbled from the pressure.  Because it was in such a vital location, failure of that member would have caused exactly the kind of accident that happened.

Especially if the worker who made this mistake was the one who died, the NTSB is reluctant to draw any conclusions in this direction that are not supported by abundant evidence.  It’s up to them to figure out what traces of such a mishap would remain in the rubble that was collected from the site, as well as whatever preliminary evidence such as photos that are available.  So rather than any nefarious conspiracy to cover up systematic wrongdoing, the delay and refusal to share information may simply be out of concern that premature release of information could lead to unnecessary agitation, hurt feelings, and even more lawsuits.  The legal system has grown to accommodate the NTSB’s role in accident investigation, and anything that would upset that particular applecart may not be helpful.

All the same, it would be good if the root causes of this very public and tragic event could be unearthed, if there are any to be found.  And other things being equal, it would be nice to have that happen sooner than later.  Clearly, something went wrong, and everyone using accelerated bridge constructions stands to learn something potentially useful from the final report on this accident.  But as the process may take months longer, we may simply have to wait. 

Sources:  The Miami Herald’s article on the NTSB preliminary report appeared on May 23, 2018 at https://www.miamiherald.com/news/local/community/miami-dade/article211735504.html.  The NTSB report itself can be accessed at https://www.ntsb.gov/investigations/AccidentReports/Reports/HWY18MH009-prelim.pdf.  I also referred to the Wikipedia article on trusses (the engineering kinds).