May 4, 2006


ready when you are?: A professor in England thinks he has a solution to commuting woes: a personal rapid transit system (mechanical engineering design, February 2004)

Creating that new transportation method is the goal of Martin Lowson and his students at the University of Bristol in England. They've designed a system they call ULTra (short for "urban light transport") that tries to be the "perfect" transit system: It's there when you need it and it takes you directly to the station of your choice.

Advanced Transport Systems Ltd., the University of Bristol spin-off company commercializing the ULTra system, has completed trials of a prototype on a test track in Cardiff, Wales. Once the funding comes through, a small circulator could be running there in a couple of years. But is ULTra ready for the real world? And is the real world ready for ULTra? [...]

Back in 1995, Martin Lowson, a professor of aerospace engineering at the University of Bristol, confronted a group of recent graduates with this very problem. "We asked ourselves what would be the ideal form of urban transport in the 21st century," Lowson said.

The team proceeded to outline certain desirable qualities for the proposed system. "What do people want? They want something that is available when they want it. They want to go where they want to go, nonstop. They want their transportation mechanism to be energy efficient, and have zero emissions."

Dealing with those constraints, the group worked up a design that disregarded many of the conventions of public transportation. There would be no drivers and no schedule. Vehicles would sit in the station, waiting to be ridden, rather than force riders to wait at the station for their rides to show up. Passengers could choose whom they rode with—or they could ride alone.

As proposed, the system would run on flat steel-and-concrete tracks elevated over streets or on the surface alongside highway or railroad rights-of-way. Automated four-seat cars would run on the guideway (the ULTra's track), picking up passengers from stations on sidings off the main line and traveling nonstop to a destination, another off-line station. The vehicles would run at about 25 miles per hour, which seems slow, but since they run nonstop, the savings in time promise to be substantial, especially in congested city centers. (More details of the system can be found at

"Once our system emerged," Lowson said, "we looked around to see if there were other similar systems that had any important aspects we had missed. And we saw that there were parallel concepts around."

Personal rapid transit, or PRT, is a concept that dates back more than 30 years. But it is hardly surprising that Lowson hadn't heard of the idea before kicking off his class project. Although PRT has a cadre of ardent advocates, the concept has never been implemented on a full-scale basis.

A compendium of PRT schemes catalogued on Innovative Transit Technologies, a Web site dedicated to alternative transportation ideas, lists more than two dozen personal rapid transit proposals. Almost all of those, however, are scarcely more than slick drawings and sketchy scenarios. Some invoke magnetic levitation to enable speeds of more than 200 mph; others propose running pods through evacuated tubes. They all seem to address some, if not all, of the ideals that Lowson and his students identified.

Posted by Orrin Judd at May 4, 2006 12:46 PM

Population density is the problem. You aren't going to get the needed density until you get rid of the zoning laws.

Posted by: Robert Mitchell Jr. at May 4, 2006 1:02 PM

By the time we get around to this the actual tracks will be unnecessary; it'll all be implemented with dedicated (HOV?) lanes and robotic taxi drivers (Johnnycab!).

Posted by: Mike Earl at May 4, 2006 1:04 PM

It's a great replacement for subways. Run them on the existing tracks, with computers as the drivers, you just enter the station you want to finish it on a computer terminal in the car, and it can coordinate with all the other vehicles. This would be a great improvement over Boston's T.

Posted by: pj at May 4, 2006 1:12 PM

OJ: As your entire theory of train virtue depends upon mistaking community for being trapped in a sro car with a hundred sweaty strangers, wouldn't this be as bad as automobiles?

Posted by: David Cohen at May 4, 2006 1:27 PM


Smaller groups like these are better for fostering communication.

Posted by: oj at May 4, 2006 1:30 PM

The voices in my head and I do not desire any other company. But thanks so much for your concern.

Posted by: joe shropshire at May 4, 2006 2:02 PM

You really have it in for the misanthropes, don't you Mr. Judd?

Posted by: Mikey at May 4, 2006 4:20 PM

Nonsense. We use Fed Ex. Never have to leave the house.

Posted by: Robert Mitchell Jr. at May 4, 2006 4:30 PM

I'm a misanthrope--public transportation never hurt me.

Posted by: oj at May 4, 2006 4:44 PM

Public transportation, nuclear waste, blows to the head with a ball-peen hammer: he's impervious to all of it. One tough cookie is our Orrin.

Posted by: joe shropshire at May 4, 2006 5:07 PM

broke a car windshield with my head and walked away from the wreck.

Posted by: oj at May 4, 2006 5:11 PM

Yes, the cars knew you for an enemy right from the start, and they tried to get rid of you, but they failed. And now you're out for revenge...

Posted by: joe shropshire at May 4, 2006 7:29 PM

Joe: Puh-leeze! That car probably called out OJ for a street fight. Or maybe OJ saw the car making fun of a caboose for not being able to leave its track, and valiantly defended its honor.

Posted by: Just John at May 4, 2006 7:44 PM

I love the talk about public tranportation. Of course, by the time the bureaucrats get around to it, I'll be well past retirement age and I'll just make my kids drive me to Denny's.

Posted by: sharon at May 5, 2006 7:19 AM

PRT is a scam and like the Zepplin, not a viable transportation scheme.

In forty years there are no PRT systems, but there have been fantastic failures including the Denver Airport luggage handling system which stuck the taxpayers for hundred of millions USD as part of the United Airlines bankruptcy and never worked.

The personal rapid transit industry is just a bunch of scammers with unworkable tech trying to get on the public dole for "research" or "testing" or some other scam, most all the companies are just a website and a shell corporation or a rumor of some shiek backing it with petro-billions.

Look up "PRT is a JOKE" on google-yahoo to get funny examples of this techno-blimp.

Posted by: joe sixpack at May 5, 2006 2:56 PM

What's wrong with zeppelins?

Posted by: oj at May 5, 2006 4:03 PM

Ah, OJ, they are forever tarred by poor goverment regulations.....

Posted by: Robert Mitchell Jr. at May 5, 2006 4:14 PM

I'm holding out for personal anti-gravity devices. However, they just might be a b**** to learn how to control.

Posted by: ratbert at May 5, 2006 5:18 PM


That's always been the problem with flying cars.

The technical kinks have been worked out, and you can buy one now, but it takes a pilot's license to operate.

Posted by: Noam Chomsky at May 5, 2006 6:00 PM

"Joe Sixpack" doesn't know what he's talking about. He preaches the gospel according to Ken Avidor: i.e. all forms of transportation other than bicycles and light rail trains should be outlawed. Avidor has maintained a mini-crusade against PRT for several years now and "Sixpack" is likely either Avidor himself or one of his disciples.

Don't fall for it. PRT is an emerging technology with enormous potential.

Posted by: A Transportation Enthusiast at May 10, 2006 5:21 PM