Elon Musk is wrong: Robotaxis are stupid. We need standardized rented autonomous tugs to move customized owned unpowered wagons.

by chaosmage 15d4th Nov 20192 min read29 comments


Sorry for the flashy headline, but I genuinely feel this might be the best idea I ever had.

After the invention of the horseless carriage, it supposedly took people years to realize that without reins to hold, the driver could now sit inside the cabin. Change of the core technology allowed a rethink of the entire product (the vehicle) but that rethink was hard.

With autonomous cars, we already have a rethink. Autonomous vehicles can be called to a person who needs it, so they should not be owned (and sit idle while the owner doesn't need to move) but should be taxis. Lots of people, including Elon Musk, agree that's the way to go. And it is indeed an improvement over the current car ownership model. But it doesn't go far enough.

The robotaxi concept retains an outdated assumption: that a single product, a single vehicle needs to do both the moving and the accommodation of the user.

Get rid of that assumption and imagine instead a system made from two very different parts that can (automatically) couple and uncouple:

  • A driving unit (tug) with the motor, driving and communication systems. This is usually rented not owned.
  • An accommodation unit (wagon) for the human(s) and their stuff. This is usually owned not rented.

How is this better than robotaxis? Lots of reasons!

  • Your personal wagon can have a bed in it, or your valuables, or spare underwear. You can use it as a movable locker, as you do every time you use a personal car to get groceries from multiple shops. You can sleep in it.
  • Your personal wagon gives you full control over the space you occupy while traveling. A robotaxi requires you to take out your stuff every time you leave and check whether the previous user did every time you enter. And what if the previous occupant used a perfume you're allergic to?
  • The tug doesn't need seats, windows or air conditioning. It doesn't need to haul all that mass every time it is called to a new user. A lot of complexity is removed from production, so these are much cheaper to build than robotaxis.
  • Renting out these tugs is much less hassle than renting out robotaxis because they need much less maintenance. They can be pretty thoroughly protected from interference by users. Charging infrastructure for tugs needs much less space than charging infrastructure for robotaxis.
  • Your personal wagon can be in a huge variety of designs and sizes! Human-piloted cars, and robotaxis, are very hard to build and only make economic sense in huge numbers, forcing standard designs that are suboptimal at specialized tasks. Unpowered wagons are much easier to build, so small production runs make sense. A small-ish company could build specialized wagon types like the self-driving office, the mobile hairdresser's salon or the Sparkly Unicorn Car that takes your kid to school.

Now that I thought of it, I can't unsee it. It seems blindingly obvious this kind of system is much better than robotaxis.

And the technical side wouldn't be that hard to do. You need a standard interface between the two, the wagon needs to give the tug reliable info about its physical properties and maybe it's worth thinking about whether one of the two can make do without a battery. No doubt I'm missing some details, but trains have separated locomotives from wagons for a long time, it can't be that hard.

There's a bit of a chicken and egg problem where you need to be sure the other part of the system will exist before you start producing your own side. But that seems solvable with sufficient clout. If Tesla can indeed demonstrate functioning robotaxis, then Elon Musk saying they're going to build tugs (with an open source coupling interface) should be enough for lots of players to start designing wagons.

So I think it's very doable. And the aforementioned advantages over robotaxis would help get rid of gasoline cars even faster than robotaxis would. And that would help with global warming. So we should all want this.

Am I wrong?