Thanks. The other asserted benefits are good but I'm going to do a little digging into the cost structure. I have recently been very unhappy when looking at the cost of light rail and that has been one of the sticking points in our county for a proposed new rail line.

I discount the benefits related to congestion for all but the biggest cities. I suspect cities strapped for cash will be forced to accept the congestion.

Thinking through this a bit, currently I'm suspicious of the capacity claims. I understand that when loading and unloading passengers the pod leaves the main track. Presumably high-demand stops would have more space to allow more pods to do this simultaneously. But there does seem to be the potential of a problem at a stop preventing a pod from leaving the main track. At this point it could stop the whole line while waiting to leave the main line (not good) or be forced to continue to the next stop.

Actually, the second option may not be so bad for the few times this occurs.

Also, such a project will compete for limited resources. These resources will need to be diverted to some fundamental areas, like rebuilding our sewers, water pipes, electric grid, petroleum pipelines, bridges and more.

Given the list of projects in the "need to have" category, I would place podcars in the "nice to have" category since it competes with simply having everyone purchase an electric scooter. This is the ultimate in flexibility and requires very few resources.

Can you make the case that podcars should go into the "need to have" category given a scarce resource environment?

Most of the list is made up promoter lies, or simply wrong or irrelevant.

Alan

* On-demand mobility regardless of age, ability or wealth.

Fails to meet ADA REQUIREMENTS. Self evacuation by wheelchair pax from jPod stalled in midair is required. Prototypes ADA unfriendly, but enough $$$ and the other defects can be fixed.

* Improved service respects the customers time, the on-demand convenience of a taxi at the cost to operate an elevator

It is an open, and unproven to date, if a real world jPods will be faster than, say, a good streetcar system.

* Origin to destination non-stop transport reduces energy and increases reliable delivery

"Jams", faults and breakdowns will NEVER occur on jPods.

Regenerative braking greatly reduces the energy requirements of electrified rail, a point Bill James ignores. OTOH, plastic on steel friction traction (the apparent motive force from what I saw) is MUCH less efficient than steel on steel.

* Time during travel is available to the traveler (unlike cars)

This depends on the stability of the ride. Suspended monorails are noted for "sway" especiall at speed. in winds and around curves.

* Personal security and safety (no muggings or accidents)

No safety provision for end to end collisions between jPods (running 3 seconds apart). Muggings are entirely possible with jPods, and prostitutes will find them cheaper than motel rooms.

* Low grade terrorist target (unlike subways)

If jPods are high visibility, they can be targeted. Hack the code, blow a beam over a river and run all jPods into the river ?

* Simple supply-chain, solar powered (most areas) networks are durable from supply disruptions.

And when the vendor goes bankrupt ?

* Multi-purpose network can move people, cargo, trash, etc....

No real world examples AFAIK. Maximum design weight and density will limit what "non-people" cargoes can be operated. Less than one ton cargo max per jPod ?

* Very few emissions improves our stewardship obligations.

But MASSIVE visual pollution that will deface attractive urban cityscapes (not such a big deal in ugly areas).

* Quiet

What about when wheel or bearing wears close to failure ? A squeal seems likely.

* High capacity, 6 to 15 times light-rail.

UTTER BS !! "Assume" one jPod every 3 seconds for a couple of hours straight, and still not quite true. The realism of such operations is a fantasy.

* Low capital costs ($4-20 million per mile, including vehicles). There are examples at www.jpods.com click on "Specific Solutions"

Promoter BS, unrelated to the real world.

* High return on investment, payback in 1-5 years, allows networks to be built with private capital and operated withou subsidies

MUCH more promoter BS.

* Simple technology

Bill James just stated that his software would ANTICIPATE demand long before it occurred and modify operations to optimize for FUTURE demand.

Scheduling and optimizing current demand would take a massively complex software program (I have read an analysis that claims that there is no "perfect" mathematical solution and all means of approximating a solution eventually result in system failure/lock-up. I did not understand the paper well enough to vouch for it's claims).

Certainly this is NOT "simple" software.

* Easily recycled construction materials. Recycle before failures (such as the I-35W Bridge in Minneapolis)

Steel is easily recycled. Concrete, fiberglass and plastics less so.

* Very small real estate foot print (2 meter circle every 30-40 meters

Massive congestion with overhead power lines and sidewalks as jPods soar over road traffic (bottom of jPod minimum of 17' above road surface ?) and then goes down to street level for level boarding by wheel chair passengers. 30 m spans seems unlikely with such dramatic changes in elevation.

The maximum slope of the track will determine just how much sidewalk will become unusable (discouraging walking).

Calculate slope required to pass over traffic and still dip down to street level mid-block for a jPod station and motion sickness is possible if traveled at speed.

* Construction does not interfer with existing traffic

Hardly possible. Portland streetcars can build 3 blocks of track in 3 weeks. Heathrow and other PRT took months to build. Some blue sky dreaming.

* Low operating costs, about 4 cents per vehicle mile. Amoritzing all costs (contruction, maintenance, rebuilding 14 year cycle) the total costs per vehicle mile looks about like 18 cents (number of variables)

BS !!

Given the constrained dimensions of the drive unit (it fits inside a hollow beam) a durable and robust drive unit seems nearly impossible to engineer.

Plastic wheels as drive wheels will create an maintenance nightmare.

Data feedback to central control and failsafe control commands from central control to each and EVERY jPod is another probable maintenance problem.

Doors are a constant and on-going maintenance headache at EVERY transit agency in the world. jPod doors require fail-safe prevention of unscheduled opening by, say, children, in mid-air. Fail safe is never cheap.

Unproven technology, drawn up on the kitchen table, will simply not last. Add snow, birds, wasp nests, etc.

My SWAG is O&M of $0.25 to $4 per VMT (first class software engineers are not cheap).

Best Hopes for Forgetting jPods,

Alan