I'm back from Burning Man, and this year, for the first time in a while, we didn't get internet up in our camp, so I only did occasional email checks while wandering other places. And thus, of course, there are many hundred messages backed up in my box to get to. I will look at the most important but some will just be ignored or discarded.

We all know it's getting harder and harder to deal with email backlog after travel, even connected travel. If you don't check in it gets even worse. Vacation autoreplies can help a little, but I think they are no longer enough.

Frequently, in reporting on robocars, it is often cited that one of their key benefits will be the way they enable car sharing, greatly reducing the number of cars that need to exist to serve the population. It is sometimes predicted that we'll need to make fewer cars, which is good for the environment.

It is indeed true -- robotaxi service, with cars that deliver themselves and drop you off, does greatly enable car sharing. But from the standpoint of modern car sharing, it may enable it too well, and we may end up having to manufacture more cars, not fewer.

Today's car sharing companies report statistics that they replace around 13 privately owned cars for every car in the carsharing fleet. Some suggest it's even as high as 20.

This number is impossible for average drivers, however. The average car is driven 12,000 miles/year. To replace 13 average cars would require a vehicle that was actively driving, not just signed out, 11 hours/day and each vehicle would wear out in 1-2 years.

Three things are happening.

• Carsharing is replacing the more marginal, less used vehicles. A household replaces a 2nd or 3rd car. Carsharing is almost always used by people who do not commute by car.
• Carsharing is often considerably less convenient than a private car. It discourages driving, pushing its users into other modes of transport, or selecting for customers who can do that.
• Related to that, carsharing shows the true cost of car ownership and makes it incremental. That cost is around $20/hour, and people rethink trips when they see the full cost laid out per mile or per hour. With private cars, they ignore most of the cost and focus only on the gasoline, if that.

The "problem" with robocars is that they're not going to be worse than having a private car. In many ways they will be better. So they will do very little of the discouragement of car use caused by present day carshare models. The "dark secret" of carsharing is that it succeeds so well at replacing cars because of its flaws, not just its virtues.

Robotic taxis can be priced incrementally, with per-mile or per-hour costs, and these costs will initially be similar to the mostly unperceived per-mile or per-hour costs of private car ownership, though they will get cheaper in the future. This revelation of the price will discourage some driving, though robotaxi companies, hoping to encourage more business, will likely create pricing models which match the way people pay for cars (such as monthly lease fees with only gasoline costs during use) to get people to use more of the product.

There is an even stronger factor when it comes to robotaxis. A hard-working robotaxi will indeed serve many people, and as such it will put on a lot of miles every year. It will thus wear out much faster, and be taken out of service within 4-5 years. This is the case with today's human driven taxicabs, which travel about 60,000 miles/year in places like New York.

The lifetime of a robotaxi will be measured almost exclusively in miles or engine-hours, not years. The more miles people travel, the more vehicles will need to be built. It doesn't matter how much people are sharing them.

The core formula is simple.

Cars made = Vehicle Miles Travelled (VMT) / Car lifetime in miles

The amount of sharing of vehicles is not a factor in this equation, other than when it affects VMT.

Today the average car lasts 200,000 miles in California. To be clear, if you have 8,000 customers and they will travel two billion miles in 20 years (that's the average) then they are going to need 8,000 cars over those years. It almost doesn't matter if you serve them with their own private car, and it lasts all 20 years, or if you get 2,000 cars and they serve 4 people each on average and wear out after 5 years.

Our technology is having trouble with settling on a name. That's OK before it's mainstream but will eventually present a problem. When people in the field are polled on what name they like, there is no clear winner. Let's look at some of the commonly used candidates:

Driverless Cars

Recently, this has become the most common term used in the press. There is a "Driverless Car Summit" and the Wikipedia page has used that name for some time.

In spite of this popularity, the term is very rarely used by people actually building the vehicles. Attendees at the "Driverless Car Summit" when polled all said they dislike it. Until recently, the most common news story about a driverless car would say, "then the driverless car rolled down the hill and careened into the other lane, hitting a tree."

My personal view is that this term is like "horseless carriage." Long ago the most remarkable thing about the automobile was that it had no horse. Here it's the lack of driver (or at least lack of action by the driver.) Of course, these cars have something driving them, but it's a computer system. While this term is most popular, I am confident it will fade away and seem quaint, like horseless carriage did.

Alain Kornhauser has proposed that Driverless Car refer only to cars capable of fully-unmanned operation, and those that need an occasional human be called self-driving. As yet this has not caught on.

Self-driving cars

This term is popular among developers of the cars. Its main problem is that it's too long to be a popular term. The acronym SDC is a reasonable one. In web hits, this is tied with Driverless Cars, but falls behind that name in searches and news mentions.

Autonomous Vehicles

This term was most popular in the early years, though it is most commonly found in research environments and in the military sphere. In the military they also use "unmanned ground vehicle" -- another term too unwieldy for the public --though they usually refer to remote controlled vehicles, not self-driving ones.

Annoyingly, the acronym "AV" has another popular meaning today. Most of the terms here are too long to become common use terms, and so will be turned into acronyms or shortened, but this one has an acronym problem.

Automated Road Vehicle

This term has minor traction, almost entirely due to the efforts of Steve Shladover of UC Berkeley. In his view, the word autonomous is entirely misused here and the correct term is automated. Roboticists tend to differ -- they have been using "autonomous" to mean "not remote controlled" for many years. There are two meanings of autonomous in common use. One is to be independent of direct control (which these cars are) and the other one, "self-governing" is the one Steve has the issue with. As a member of the program committee for TRB's conference on the area, he has pushed the "automated" name and given it some traction.

Unfortunately, to roboticists, "automated" is how you describe a dishwasher or a pick-and-place robot; it's a lower level of capability. I don't expect this terminology to gain traction among them.

Highly Automated Vehicle (HAV) and Automated Driving Systems (ADS)

For some time, HAV was the term used in NHTSA proposed regulations. It never caught on. The new regulations use ADS, it is unclear if this will catch on -- the acronym of course is an English word so it can't easily be searched for.

Robocars

I selected this term for these pages for a variety of reasons. It was already in modest use thanks to a Science Channel documentary on the DARPA challenge called "robocars."

• Talking to teams, they usually just called their vehicle "the robot" or "the car."
• It is short, easy to say, and clear about what it means
• It is distinct and thus can easily be found in online searches
• It had some amount of existing use, notably as the title of a documentary on the Science Channel about the DARPA challenges

However, it is doing poorly in popularity and only has about 21,000 web pages using it, so I may need to switch away from it as well if a better term appears. Today it reminds people too much of robotics, and the trend is to move away from that association.

On the other hand, no other term satisfies the criteria above, which I think are very good criteria.

Southwest recently announced a very different approach to providing in-flight entertainment. Partnering with dish network they will offer live TV and on-demand programming over the in-plane WIFI to people's personal devices. Sadly, for now, it's just Apple devices. I will presume they will extend this to other platforms, including laptops, soon, and they should consider also allowing you to rent a tablet one-way if you don't have your own.