Sunday, June 26, 2011
I know, acronyms are often useless, contrived and perhaps a bit tacky. And I suppose I could, in the past, be accused of trying to shoe-horn meaning into the word “SMART” or “SMARTS”, as seen in (posts 53 & 54 … Small-scale Modularized Automated Rail Transport System) Now, of course, there is even the “Smart Car” to get confused with. Well, here I am again, same word, new meaning. I guess it’s a character flaw. Anyway, here is one that embodies a point worth considering.
Standardized Multi-axis Automated Rail Transport. There. I said it.
“Standardized” because it involves permanent (or at least semi-permanent) infrastructure. Let’s face it. Some VERY big companies have filed for bankruptcy in recent years and no city wants to be left holding the bag if their PRT company goes under. If an untried infrastructure is contemplated, then “open-source” style standardization gives at least a bit of assurance that the track will be useful even if a given PRT provider goes belly-up. Standards are everywhere in modern life and essential in almost every field of endeavor. At the very least a system’s viability should not be dependent on a lot of proprietary technology. Who would buy into that? Standardization serves to extend the usefulness of any system by promoting development of parts or accessories by third parties, and gives them continuing incentive to innovate. Standardized track would enable all vehicle manufacturers to compete and exercise their know-how, so it is a natural division between what is standardized and what is proprietary.
“Multi-Axis” because the main obstacle to speedy ground mobility is the need for long ramps to switch from one level to another. As I have pointed out in previous posts, objects moving around on a (2D) plane must either wait for each other to pass or leave that plane to go over or under each other. The larger the objects and the greater the velocity, the larger the ramp structures needed to accommodate this action. Since the vast majority of traffic is in the movement of puny humans, building giant structures that rival the pyramids of Egypt all over the place is not a very rational way forward, especially in these days of fiscal austerity. Although some PRT designs are essentially two dimensional, being raised to an essentially fixed elevation, I personally feel that this approach is shortsighted. I fear that once PRT is found valuable and useful, a new generation of more versatile multi-axis designs will appear overnight that will leave these systems seeming quaint and old-fashioned and their track obsolete. Of course that is just this author’s opinion. There are many reasons to “design in” the ability to ascend and descend within a small footprint. Some neighborhoods might wish to raise the track quite high to minimize the system visually. In such cases the vehicles would descend to the stations, even if those stations were elevated. There are cases where elevated stations are impractical or too costly. Having sufficient stations is paramount, so being able, for example, to descend to ground- level bus stops or parking lots would be very useful. Such situations would be impractical with long ramps, since they would tend to block private driveways and be visually intrusive. If industrial or warehousing applications are considered, true 3D travel would be extremely useful.
Rail – Because it is smaller, lighter, easier to produce, transport and recycle, and can be designed to lock a vehicle on track in all situations, such as bad weather. It is the best solution (short of flying) for true 3D mobility. I know that rail is a contentious issue, and that many would say that a system like ULTra, whose vehicles could be easily be modified to freely roam any pavement is better. Whereas I can understand this logic, I feel that the long ramps and the canopy effect inherent with such systems trump this argument. Remember, even though the guideways may be only a bit wider than the vehicles, every time there is a fork for a station this dimension is doubled. If there ever needs to be a two-way application, this implies up to four overhead “lanes.”
Transport – not transit, because we are potentially talking about light freight as well as people, particularly at night. In fact I see a lot of potential use in industry, such as automated warehousing and shipping. I would point out that the whole way warehousing is currently done is to aggregate goods together to minimize many separate deliveries. The ability to pick up and move small loads without a driver could change that, allowing goods to be staged much closer to their destinations. Taking some trucks as well as cars off of the existing road system can only be a good thing.
This is a fundamental shift from simply calling for PRT. Back “in the day,” PRT was revolutionary because it was automated and electric, but those features seem increasingly minor in today’s world. Is the full automation of PRT really the point? I could imagine a PRT vehicle that would be capable of processing passenger input on the fly… for instance a last minute decision to go around the block because you had mistakenly passed your destination. Or perhaps a scenic tour… (“Take the next right.”)
So if it is not really about centralized automation, nor strictly about transit (for humans) what exactly is it about PRT that is so important? Is it about “Personal?” That is a bit troubling if by “personal” you mean transporting one person from a unique point of origin to a unique destination, at least in the short-term. No early network will be that extensive, and skeptics need to see a shorter term payoff. Is it the small payload we are after? Partially; I would say that we are after payload-appropriate scaling, both in the vehicles and the infrastructure they run on. This, of course, encourages the more extensive routing that meaningful networks require, thus leading to that promise of non-stop, point-to-point travel. Naturally a smaller scale system can be much more economically raised so as to avoid traffic on the ground. These aspects, I think, should be the emphasis, more than “PRT” per se.
When I try to explain PRT to people, their eyes glaze over. PRT is the solution to a whole set of problems that must be considered in unison for it to fully make sense. PRT is a “hard sell” for precisely that reason. How can you get someone to sit down and try to imagine the limitations of all various future combinations of robocars, smart lanes, and electric cars if they are not so inclined? Yet that is what they must do if they are to realize that these technologies aren’t the full answer. If we want to sell PRT, we first need to be able to reduce it to its essence – to start with the aspects that no other system can match.
Breathe deep and say it with me now… “We need a supplemental transportation infrastructure.”
There. Feels good to put it into black and white, doesn’t it? You’ve just cut through all of the explanation of PRT, Dual mode, etc. and put one of the world’s next great challenges into a simple phrase that most people can wrap their heads around. We need a transportation infrastructure that is designed to do more for less. One that can relieve us of the huge costs of continually building and maintaining more and more gigantic highway projects. Stoplights are a ridiculous waste of time and cloverleaf interchanges are a ridiculous waste of real estate. We desperately need a third option for economically crossing paths without waiting or colliding.
We need a supplemental transportation infrastructure that is scaled to be appropriate for the task. We have many, many small objects, (including humans) that are coming from many points of origin and need to be moved to many separate destinations. These days it is no longer necessary to aggregate cargo and people into great groups and move them in mass. (At least for land travel) Modern manufacturing techniques can spit out hundreds of small vehicles with the same ease as a couple of big ones. Electric vehicles don’t need to be big to achieve mechanical efficiency. The land is already cleared and ready and we have plenty of infrastructure in place for heavy cargo in the form of existing roads. There is no reason to build more enormous concrete interchanges when the traffic is coming primarily in the form of small payloads that could very easily slip by each other in a more appropriately sized system.
I said it in my very first post. We have to make people aware that the current roadway paradigm is insanely wasteful. The future will be bleak indeed unless we make the kind of efficiency leaps in ground transportation that have been made in other fields. It is totally crazy for 160 lb. person to need a 4000 lb. vehicle and eleven million pounds of roadway to get to a grocery store a mile away! And yet not even be able to travel non-stop!
Oh yeah, about that picture… If everyone in every vehicle just pulled over and lined up on an overpass (and they were all wearing white) this is what it would look like. (What looks like a white stripe is actually about 120 little marks sized to represent people.) Clearly this maze of concrete is insanely huge for the function of allowing those tiny white marks to move past each other unimpeded. Since it must be designed to accommodate bumper-to-bumper fully-loaded eighteen-wheelers, form does not match function when it comes to moving these commuters. Only one in ten vehicles in this picture is a truck, and it is questionable how many are traveling with heavy loads that could not be broken up. By the way, did you know that, in terms of smokestack-style industrial processes, cement production is second only to power plants in the emissions of CO2 produced?
Let’s hone the message… We need a supplemental transportation infrastructure that is designed to inexpensively and efficiently provide fast, non-stop travel without blocking any other traffic. That can only be done with a system specifically designed for economical multilevel routing. Here, economical multilevel routing means small, and that is just as well, because it coincides with the idea of individualized point-to-point travel.
A multi-axis rail system for transporting people-sized loads without getting in the way… Call it PRT or something else. Either way, it’s a “SMART” idea! OK, that WAS a tacky ending…