Brad Ideas - Robocars vs. PRT - Comments

Much, much cheaper

brad — Thu, 17 Mar 2011 16:48:48 -0700

At-grade is vastly cheaper. If you can do it safety with new technology, it means you can do it for far less, and that means getting a lot more for the same money. The choice in most cases will be to have the at-grade system or to have nothing. If you have $1B for separated and that will buy you 5-10 miles at today’s prices, or hundreds of miles at grade, which are you going to pick? And in many cases, the at-grade is already there.

Why own

brad — Thu, 17 Mar 2011 16:46:24 -0700

There are cities where car ownership is a sign of great wealth, like Hong Kong. But while half the time I get comments like this (who would bother to own?) the other half of the time I get the reverse (people will never give up their cars.)

Only the future will answer this. It will go both ways. I think a lot of people will give up their cars, but many won’t. The reasons they won’t give up their cars include:

They like to customize it, fill it with their own stuff (not just in a locker in the trunk.)
They like to use it as expression of their style
They are absolutely assured to have just the car they like
Storing it is no longer so expensive
They can rent it out (if they keep it clean) to others and thus afford a better car
They are developers, or companies.
They have kids and trust only their own car with their kids most of the time.

It will be more expensive. But we already are willing to spend a lot to get a car these days.

Why personal cars in a robocar world?

DensityDuck — Thu, 17 Mar 2011 15:23:31 -0700

Lots of discussion about parking, but in a robocar world, why do you *need* a personal vehicle? Why not just rent one from a central facility?

Indeed, "personal vehicle ownership" could become an expression of ultimate luxury--"he's so rich he can afford his own car!" That would solve the problems of working out parking for personal vehicles by making it be entirely the owner's responsibility.

Sort of like horses. Nobody worries about where to put the hitching posts and watering troughs outside a modern building. Pretty soon, people might feel the same way about parking lots. Why worry about where to park? The car just goes back to the garage when we're done with it. And people who own their own cars can make their own arrangements, with the understanding that not everywhere is going to be equipped to support personal vehicles--just like not everywhere, these days, is equipped to support horses.

BART grade crossings

DensityDuck — Thu, 17 Mar 2011 15:13:07 -0700

I think this is the first time I've ever heard someone say that non-grade-separated rail design is *preferable*.

If nothing else, the Houston Metro ought to show why grade separations are a good idea.

Smoother ride

brad — Mon, 07 Mar 2011 19:21:42 -0800

Yes, to be more correct, what I mean is that tires make a smoother ride on the same surface. The rails themselves are usually much smoother than road pavement, and thus the steel wheels on rails ride is smoother. A tire ride on pavement as smooth as rails is would be best.

I have optimism, as yet unproven, that computer controlled suspension might allow very smooth rides on any kind of surface. A real time laser scan of the upcoming service would cause control of magnetic suspension for example.

This would be cool

brad — Mon, 07 Mar 2011 19:08:44 -0800

But the management of railroad tracks is currently quite archaic. Headways (allowed distances between vehicles) are massive, many minutes, and all designed around trains which can’t stop in time if the engineer sees something on the track.

Small light vehicles of course could stop quickly (even more quickly than cars can if they can squeeze the rails) and also accelerate quickly. And if designed for it, leave the rails if there is a place for them to go. But there is still the issue of a vehicle stopped on the rails and what to do about it if a train comes, and getting rail lines to adapt to the idea of small vehicles using the rails.

How robocars might help rail transit, particularly long distance

Ricky — Mon, 07 Mar 2011 10:55:53 -0800

I was thinking that hybrid robocars might be a better idea than road-only robocars because it is not one infrastructural system, but two, that are commonplace - not just roads, but also rail. Furthermore, the robocar would be able to extend passenger railroads' reach by essentially eliminating the train station (or at best rendering it redundant), as well as sidling up promptly to the train stations (for the traditionalists, anyhow). This measure would require building tracks on the sides of rail mainlines, and a method for connecting robocars to trains so that passengers would be able to go between vehicles safely. (If there are too many pax or if they are too slow, they could slow down the vehicles, or detach from the train and chase after it to try again on the next spur. Warning would be provided and the doors would shut before detachment.) The idea would be for robocars to sidle onto the railroads and run down the rails, deposit passengers, pick up passengers, and go either to the destinations or to home base, presumably the old train station. I furthermore suppose that this opens up the possibility of new highway vehicles of a similar nature to railroad trains, in which case the robocars attach to what is essentially a large robobus and allow passengers to get on and off. Once aboard, people would be able to shop, chat, socialize, do business, relax, and have fun. Once they near their destination, they would disembark to a robocar, whereupon they would head off to their desired doorstop. Robocars would then go either hunting after new passengers or back to the robobus or robotrain areas.

This sort of system might help make so called boondoggles such as Amtrak more user-friendly by improving flexibility and allowing rental cars to show up at far-flung stations without any need for someone to drive them.

Sure pneumatic tires are smoother?

Ricky — Mon, 07 Mar 2011 10:41:14 -0800

I've tried to do work on the NJ Turnpike (one of the smoother and better maintained roads in NJ) and on the Northeast Corridor and other rail lines, and I found rail to be decidedly smoother. Granted, this may be at least partly the result of the pretty snowy January, but, still, it seemed to me that rail made the better ride (and this includes light rail, in the form of the Hudson Bergen Light Rail Line).

The short term and extended synergies

Ryan Baker — Mon, 24 May 2010 22:06:41 -0700

I share your sentiments that robocars are inevitable, but diverge from you in the short term implications, and think the final model you propose makes too many sacrifices for the sake of simplicity.

A long term solution that includes narrow, cheap, elevated guideways is preferable for a number of causes, with only minor drawbacks. You mentioned many of these advantages, but seemed to have dismissed them.

Energy Efficiency - via lower rolling resistance.
Energy Efficiency - via no stopping due to pedestrian interference.
Energy Efficiency - via lighter weight vehicles due to battery size reduction.
Energy Efficiency - via lighter weight vehicles due simpler suspension.
Cost - via cheaper $/mile for additional capacity.
Cost - via cheaper $/mile where elevated track is necessary/desirable.
Visual appearance - via narrower guideways where elevated track is necessary/desirable.
Parking - if everyone owns a vehicle that includes it's own propulsion, storage space is large.

So, the solution I would advocate long term is a mixed system with the following components:

A rubber wheeled robocar "sled".
Both public and privately owned "compartments".
A PRT guideway network, probably a suspended system.
Some single mode PRT vehicles.
Some walk-up single mode PRT stations.
Some dual mode PRT "carriers".
Some automated dual mode PRT stations.
The existing road infrastructure.

In this system, in urban areas the sleds would probably be operated by a public utility, or via groups of private service companies. Private sled ownership is feasible, but would generally be discouraged in urban areas due to parking. In rural areas it may be common to have plain robocars, since guideway may not be common.

The benefits of this system confer mostly to urban environments but in addition to those mentioned before would also include:

Walkability - Too much robocar would exacerbate the unhealthy non-walking culture. Single Mode PRT stations however would preserve walkability while also providing cheap, efficient, fast urban transport.
Road reclamation - Some local streets could be converted from thoroughfares, to grass avenues, and only rarely used for local delivery access.
Road reclamation - Some elevated highways could be removed after replaced with guideway, allowing broken neighborhoods to reunite.
Reliability - Suspension/engine/navigation ownership requires personal maintenance, which if neglected could pose risks others.
Reliability - Suspension/engine/navigation ownership requires personal maintenance, which could be a personal hassle.
Cost - Suspension/engine/navigation ownership would be more expensive than a share infrastructure.
Parking - Personally owned compartments could be stacked in ultra-compact automated garages. Full robocars would be more difficult by requiring larger amounts of space, special care in handling wheels, and vastly larger weight (most of a vehicles weight is in engine and suspension).

For all these reason this is a more logical long term model. In addition because a Single Mode system is a component of this system, investing in it in the short term while robocars are completed is still a logical step. The dual mode components I would imagine entering the system around the same time as the robotic control itself.

You could read more about my early musings on such a system here: http://tech.norabble.com/2006/03/transportation-concept.html

What's an easier sell?

brad — Tue, 26 May 2009 19:44:51 -0700

Yes, that is the leap. A not yet ready technology could indeed spell doom for a simpler, but also unimplemented technology. Happens all the time in high-tech.

Robocars will not get on the road until they demonstrate their safety of course. And while that’s something that seems, and is, further away technologically than dedicated ROW vehicles like PRT, PRT faces all these non-technological obstacles. They are outlined in detail in the relevant article.

The first working (and certified safe and legal) robocar can be bought by any early-adopter individual. And on day one it can go everywhere that has accepted the legality, which would certainly mean everywhere in a city, for example. The first PRT has to be bought by an innovation-averse city transportation board, and on day one it can take you only between PRT stops.

Thus the difference.

Wait.. so a technology not

Anonymous — Tue, 26 May 2009 18:17:46 -0700

Wait.. so a technology not yet available should be seen as a stepping stone to one that is?

And why exactly will RoboCars be easier to sell than PRT? Nobody is worried about PRT jumping a curb and killing a bunch of people because of a software bug.

Does not serve children, or the old, disabled and infirm

brad — Thu, 02 Oct 2008 01:28:47 -0700

You could not get a transit system like this today (even if it were a good idea, which I am not sure it is) because it doesn’t deal with the disabled, or others unable to walk to the e-bike depot or ride the e-bike.

It also does not work for shopping. To work in bad weather, you would need not bikes, but some sort of sealed vehicles.

What about this kind of system instead of robocars or PRT's

jim moore — Tue, 30 Sep 2008 20:38:53 -0700

For intra city transport I think that the key is to use a hub based transport system. Every type of transportation technology has distance range over witch it best suited. I would like to suggest that for intra city travel 3 distinct modes of movement should be used. Walking is ideal for distances of 1 to couple of 100 meters ( now of course walking for much longer distances is easily done just more costly in terms of time.) Next comes bikes / electric bikes / electric scooters / segways? which are good over the distances of ~100 meters to ~ 5 kilometers (~ 3 miles) (again you can go further but it becomes more costly in terms of time) Finally you get buses which would be used for distances of ~ 5 kilometers to ~ 100 kilometers (the width of the city).

Depending on density you have a transport hub in the center of a circle with a two to five kilometer radius. You have enough hubs so that everyone in the city is at most 5 kilometers from the nearest hub. Buses only travel between hubs and they only pick up and drop off people at hubs. To get from from the hub to your destination you are a member of a bike / scooter / segway share program that has big depots at every hub and little depots on just about every block.

So a commute would go something like this; you walk out of your house to the e-bike depot at the end of the block. You hop on a e-bike and ride the mile to the nearest hub (time from house to hub less than 5 minutes). You drop off the e-bike and hop on the bus to the hub nearest your place of work ( with fairly regular travel patterns it might be possible to optimize the the bus system so that you go directly to your destination hub without stopping at other hubs along the way). At the destination hub you pick up a different e-bike and ride to your work place which has an e-bike depot.

I think this type of system would be efficient, fast, flexible and inexpensive.

About rails

brad — Tue, 30 Sep 2008 11:29:22 -0700

I will also add that steel on steel is typically quite noisy. While pneumatic tires are slightly less efficient in rolling resistance, they make a smoother and quieter ride.

Can't simulate yet

brad — Tue, 30 Sep 2008 11:26:14 -0700

All we could simulate today would be not very smart algorithms. For parking lots we could probably simulate. I don’t think the algorithms used by Valets in valet parking lots show any particular genius. When I got to the valet lot, they ask me when I plan to leave. Even when I am off by quite a bit, it’s never much of a problem, and they pack those lights so tight you can barely walk between the cars. Part of the algorithm is to make both the cars leaving soonest and the cars with high uncertainty less blocked than cars with higher certainty.

Different from the Valet world, I expect the user to signal on their cell phone when they wish to leave, and that this will often take place several minutes before they get to the street. Most people have this sort of advance warning leaving offices, restaurants, parties and shops. Morning commuters know when they are finishing their breakfasts, and they usually have a pretty close idea of departure time in any event. In many cases events will be on the person’s digital calendar. Even if the calendar is wrong and the event runs late, as is often the case, it just means their car is more available than it needs to be for a while, no big whoop.

On a street, first we would see a lane of cars that fills the street. When it is time to add a 2nd, double parked lane, the parking controller computer on that street (just a local computer though it no doubt talks to the a more general parking controller) would look at the estimates and uncertainties and do the double parking as follows. It would find the car in the curb lane which is leaving soonest, and tell that car to move to a double parked position. The newly arriving car, which is most likely leaving later, would then take the vacated spot. As new cars arrive to double park, in most cases a car leaving sooner would vacate a curb spot and move to the double parked spot. If somebody needs their car in a hurry, then at most they just have to wait for the car that is blocking them to move out temporarily.

In fact, in the vast majority of cases, the double park lane will not be full. It will have at least one gap in it. In fact, the parking algorithms might decide to always leave one gap in all lanes, except the curb lane, even if doing quadruple or triple parking.

If there is a gap (long enough for the longest car stored inwards) then a whole chain of cars can move together, forward or back one space, to move the gap so it is positioned for the car that needs to leave. Then they can move again so that the car with the longest predicted stay can move into the vacated spot, it can be kept vacant and another car can enter.

This algorithm allows very dense parking and in fact if you leave these gaps you don’t even need to prioritize the cars by departure time because any car can get out in just a few seconds no matter how deep. It took me just a few seconds to think of this, and I am sure that people looking at the problem harder will find solutions even faster.

I am not endorsing the status quo. I am just saying we have enough, and robocars will give us more, and as they do, we can convert old parking lots to something nicer, or add more pedestrian areas to streets and so on.

PRT guideway can only be a robocar conduit if it’s more general, like ULTra. Many planned PRT guideways, such as suspended monorail guideways, steel truss rails etc. would require very special robocars for use. While people would probably buy such cars if it got them a faster trip, there would be extra cost.

Robocars vs. PRT

brad — Thu, 25 Sep 2008 14:00:14 -0700

Readers of this blog will know I used to talk a bit about Personal Rapid Transit (PRT) but have switched to a belief that it is now likely that robocars might fulfill the PRT vision before actual PRT can. To understand that, it is necessary to explore just why PRT has never really come about, in spite of being promoted, and possible for almost 40 years. The Morgantown Personal Rapid Transit has run since 1975, though it uses large vehicles and only has 5 stations, so it doesn’t realize the PRT vision of personal cars that go point to point in a network of stations. The ULTra system, with personal cars (which run on tires in a simple track) is being built at Heathrow airport.

I wrote an article on the reasons I have rejected classical, track-based PRT and then opened discussion on it in the Google transport-innovators group. The thread was quite vigourous. I had expected PRT fans to not welcome the concept, and to believe that robocars are still very distant science fiction, for indeed that is a valid objection.

I had not expected such a love of the general concept of shared transit that I would see people arguing that even if robocars were arriving soon, it would still be better to fill our streets with custom elevated guideways for a PRT system. Indeed, some advanced that we should not be building roads at all, that people would give up entirely on vehicle ownership in a PRT or robocar world and that providing garage to garage (or door to door) service was not necessary in the U.S. market, or could easily be done by just running PRT tracks to every house.

I understand the frustration in the PRT world. The ideas make a lot of sense, but no city will buy them. I contend that’s because municipal transit planners are highly averse to innovation. They are happy to buy 100 year old technology for their cities. They think farecards and web sites that can tell you when a bus will get to your stop are space-age innovations. Nobody wants to be the planner who bet on an untested technology that failed. That’s a career-ending risk. They would rather bet on old technology, and in spite of how well it is understood, see it go 100%, 200% or more over budget.

I predict that, once the technology becomes more real, robocars will win because they will be built bottom-up on a simple, already existing platform (roads) without any requirements to build infrastructure or run it. They will be bought by individuals, in particular by early adopters. Early adopters have money to burn on the latest hot new toys. They will happily waste it and buy the cooler model 8 months later. Cities don’t buy this way, they can’t. Cities buy technology that’s already obsolete before they even put it out for bid, and it’s very obsolete a decade later when it goes into operation.

Worse, transit requires monopolies. Either the city runs the transit as a monopoly, or it grants a franchise to a private company to build and run it. (That’s far more rare, since most transit runs with heavy subsidies in the USA.) Monopolies mean corruption (as they get large, they end up having more influence on the city officials than the customers do) and they mean monopoly-style customer service.

While robocars are still over a decade away, I fear that even though PRT could be built today, it will take it a decade to get over the marketing humps it has not managed to overcome in 40 years. By that time, robocars should be much closer to reality, and we’ll reach a point where even a transportation planner will realize the robocars will arrive soon enough to affect transit planning in the present.

Rather than being viewed as the enemy, robocars should be viewed as a way to realize the PRT vision without those deal-blocking new infrastructure requirements. But the PRT community is not yet ready to agree.

Read Robocars and PRT