Now that we've all seen Elon Musk's ideas for his Hyperloop system we can indulge in the wonderful pastime of musing over whether it will work. Musk's blog post on the subject is here and it links to the full proposal .pdf. My colleague Hannah Elliott has more here.

From the various things being said by the engineers who have looked at it there seems to be little doubt that it is technologically possible. As one definition of whether it will work is "can we do it?" then we can indeed say that Hyperloop will work.

I do have a quibble or two: one is about rights of way. Just because it will go on piers beside existing freeways doesn't mean that there are no problems with the acquisition of the route and the land for it. But that is just a quibble.

It's also very definitely a point to point system. There aren't going to be intermediate stations, you can't take it from LA to Bakersfield (or any other town that it does actually go past). And while the trip itself is very fast, it suffers the same problem as all point to point systems. You've got to get to the start point from wherever you are and then from the end point to wherever you really want to get to.

This means that while LA to SF might be superfast I'm not entirely convinced that Ventura to Berkeley or Stanford (if anyone ever actually wants to travel between those points) is going to have a particularly different total transit time than current practices: whether car or airplane.

But these are all quibbles in the grander scheme of things. The real reason I think that it won't work is because speed of travel just isn't as important as it used to be because we've got these driverless cars on the way. Apologies, yes, this is one of my little bugbears and I've mentioned the point before. This same point applies to the high speed trains that are currently being built (well, people are wondering where they'll get the money to build them) in California.

The point about high speed travel is that time spent in traveling is dead time. You can sit there and relax, sure, read a book, chat to your friends and or family. But you cannot actually do any useful work. And since business travel is very much the point of this sort of high speed travel the economics rely very heavily upon the time saved by those highly paid people in their travels.

The actual method that's used is to assume that someone who is paid, say, $100 an hour loses $100 for each hour that they spend in travel. They could have been in their office earning instead. So, if we have a trip that takes three hours instead of five then that person has saved $200. The value of the faster train is thus $200 to that one passenger: aggregate all of those time savings at some presumed value per hour and we get the societal benefits of this faster method of travel. This really is how we calculate the value of a fast method of travel.

The problem with this is that assumption that travel is dead time. It most certainly used to be, this is true. You're on a train, in a car, sitting in an airplane, you cannot actually do much more than sit there or some form of leisure activity. But this really isn't true these days. We've all got mobile phones, laptops, we can all do very much the same sort of work we do in the office while we're traveling around. Which means that this travel time isn't dead time: thus faster travel doesn't have the same benefits we used to calculate it does.

Sure, there's still benefits to faster travel: just not as much as there used to be. And certainly not the large economic impacts that are generally assumed there are. Simply because we can indeed now work while traveling.

Further, this is going to get better and better. I don't think that it's too extreme to think that Google's driverless cars are going to be a common private vehicle in a decade or so. And we can already stick WiFi in a vehicle, that's easy. At which point sitting in one's car is going to be very like actually sitting in one's office. It'll be a productive time: and if the time spent traveling is productive then the value of faster travel falls precipitately. In fact, I think that we can reasonably predict that travel by driverless car will become the preferred method of travel in the near future. I'd certainly prefer to do the Ventura Monterey trip (one I have done a number of times) in my own car that I didn't have to drive but was internet connected than I would travel over to a station, wait around, take a train or Hyperloop or even plane, pick up a rental car and go to the destination. I'm not entirely convinced that elapsed time would be all that different: but my time wasted would certainly be higher out of the car than in it.

The bottom line of this is that all forms of faster travel are becoming markedly less valuable. For we're developing the technologies that make the amount of time spent traveling markedly less important. This isn't exclusively a point for Hyperloop, it's relevant to all forms of transport. Supersonic air transport is less worthwhile now than it was, high speed trains, the Hyperloop. Simply because we can now do other productive things while we travel the speed of travel itself is less important.

I've no doubt that the Hyperloop could be built and could be made to work. What I don't believe is that it will be worth doing: for the purely economic reason that time spent traveling is no longer unproductive time. Thus the value of high speed travel has fallen.