The idea of separate light/slow and heavy/fast transpo nets is intriguing, but still strikes me as oh-so 19th century in terms of what it works with. It doesn't really exploit the capabilities now in hand to use InfoTech (IT) to manage different forms of mobility, which are only bound to become more diverse and indeed too diverse to put into discrete LLM-FHV conceptual boxes.

The era of the truly "smart" car (or truck, or bike or segway or whatever) hasn't even begun yet. It seems more likely that the real breakthrough will come when someone, somewhere cuts through the institutional barriers to fully applying IT to mobility (failsafe collision avoidance, fully programmable and automated navigation, etc.). At that point, truly value-enhancing accessibility networks will begin to self-assemble in ways that no one can today sketch in advance.

Yeah, i think it's a neat "academic" exercise...right up there with how many angels can dance on the head of a pin LOL

What, are we going to rebuild every community on earth? Even for the new ones...we're going to pave twice as many roads so that each type of vehicle can have it's own path? Just one of those strange exercises that I don't see translating to anything practical.

The two traffic mode utopia already exists. Dr Delucci simply needs to spend a day in a tier 1 Chinese city and observe street traffic.

There you will see the bike lane occupied by about 5% pedal-only bikes, 75% pedal/electric bikes, 10% gasoline pedal bikes and 10% gas or electric only scooters and motorcycles.

You will also see the car traffic with acceleration rates like the US, and following distance and aggression and congestion like most continental European cities.

Traffic streams, of course, have to cross each other peridiocally, like at intersections. In China, the bigger vehicle gets the right of way (is this is communist tradition?)

After observing that traffic flow, Dr Delucci could then write about the limited practicality of low speed four wheel BEVs, since even at 500kg they are not maneuverable enough to share the slow bike lane traffic with bikes and scooters, and when they are out of charge, they are not easily pedaled or pushed.

Pie in the sky coming from an ivory tower.
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However, i have often wished that there was a "true" bike lane, as in a completely separate roadway.
Or, at least certain roads that were completely dedicated to bikes and/or alternative scooters.
For example, say, 5th Ave in NYC restricted to bikes only. Anybody on a bike needing to travel north/south would not have to risk their life with autos.

I'm conceiving an alternative system that involve overhead bikeways in congested downtown areas. Dedicated bike ways are not hard to implement in skyscraper downtown, as they can be built overhead adjacent to the building where these skyways receive support from the buildings directly. These bikeways allow the riders to be completely insulated from the severely congested streets wherein cars and buses are traveling at nail paces. These bikeways can further be covered from the outdoor elements, protecting the riders from harsh winter weathers, mud and snow. The bikes can be easily rented by tourists, so that they can easily travel to all downtown buildings such as hotels, shopping, convention centers, office buildings etc. without causing more congestion in the streets below, and at much faster speed, without stoppage due to traffic lights or crossing traffics, and completely protected from all other menacing vehicles.

@ Roger_Pham:

I am not sure that the bike-hards (or taxpayers) would embrace your scheme, but there are sure a lot of close-to-reality and 'should' be close-to-reality european/dubai schemes out there:

http://io9.com/5362145/a-bicycle-superhighway-with-timed-lights-for-copenhagen

http://www.been-seen.com/article.cfm?id=11204

http://io9.com/5150299/personalized-podcars-float-over-abu-dhabi

Thank you all for the feedback and the references. The bicycle is neat because it is very compact to park, non-polluting and very energy-efficient. A one-way commuting distance of up to 10 miles (16 km)is still practical for a bicycle. Those who are not physically-fit can use electric-assist bicycles using Lithium batteries. A bicycle-centric city is much more compact than an automobile-centric city and cost much less to live in and much more energy-efficient. I also envision a segregrated bicycle lanes that resemble existing HOV lanes for autos, in all major streets and freeways. Entry and exit from these bike-HOV lanes is done by overpasses in order to provide complete segregration from auto traffics. Bicycle overpasses can be built over all traffic intersections, thus allowing uninterrupting traveling that would make up for the slower speeds of the bicycles. Bicycle overpasses and skyways are very light in construction, and can be mass-produced in factories in modules that can be quickly assembled in a few days at the final locations. A high-strength steel and truss-like structure is strong enough to span a very long distance, thus requiring few supporting columns, where it is inconvenient to build supporting columns. A concave bikeway can be narrow, yet can allow for automatic stability without requiring much attention from the rider. In residential neighborhoods, bike lanes can be built adjacent to walkways in the front lawn, thus less grass surface areas that would require irrigation and lawn care, thus save water and lawnmowing expenses.

I certainly miss my childhood days riding my bike to school and all over the city, complete freedom of mobility without incurring major expenses such as car payments, gasoline, repairs, insurance etc.

Thanks, ai vin, for the references. The Velo-city concept is about what I have in mind, except that I would advise against bi-directional traffics since the risk of head-on collision would be too dangerous, and that the skyway would be too large and too imposing, an inherent aesthetic issue. One-way traffic would be far easier to implement when it comes to interchanges of East-West skyway and North-South directions etc.

This was all supposed to be just another episode of the Jetsons.

Hi all, I’m the author, Mark Delucchi. I’ll respond, in order, to all of the 19 comments so far.

#1, dhofmann. Presumably, people will feel safer using an LLM (light-weight, low-speed mode) network that makes it physically impossible for LLMs and FHVs to interact, and if people feel safer, then presumably they will use the LLM network more. I believe that this difference in actual and perceived safety is critical: most likely, few people will use LLMs in mixed traffic, but in a completely safe, zero-fatality, dedicated LLM network, people might take up to 40% of their trips. As you note there is a cost to having a completely separate network, so it is interesting to think about changing the design to reduce costs and design constraints without greatly increasing the perceived danger of the system.

#2, John DeCicco. (Disclosure: John is a long-time friend and colleague.) The design does not preclude or inhibit the use of IT systems or smart cars; indeed, it might create new opportunities for their application. For example, one can envision a small-car-sharing system intelligently integrated with the light-rail system in the town center. And it might be easier to design collision-avoidance systems for FHVs if there are no LLMs around. So, the question is not whether to have our design or to have IT and smart cars; the question is, given whatever IT bring us, does it make sense to have a system such as my colleagues and I propose? (As an aside, I caution against putting too much faith in things like failsafe collision avoidance, but that is a conversation for another time.)

#3, ToppaTom. I don’t understand your comment.

#4, DaveD. The plan is for new towns and developments. There won’t be twice as many roads; in fact, the total paved area and road cost probably will be less than in a conventional network, on account of the geometry of a radial system compared with a grid, the narrowness of the roads, and our system of shared driveways.

#5, Jer. The plan is for new towns, and certainly does not require that everyone live the same way. Indeed, by offering an alternative transportation network with a wider range of modes, it gives more choices and more life-style alternatives than does a conventional system. It neither forces people to live in dense cities and take conventional transit (or walk) nor condemns them to monotonous car-only suburban living.

#6-7, Frankbank. There is no system in China or anywhere else in the world that has the key features of our design: two completely separate yet universally accessible networks, segregated according to kinetic energy (rather than motorized versus non-motorized). Where there will be a significant amount of motorized and non-motorized traffic on the LLM network, non-motorized traffic will have its own lanes.

#8, danm. More specific criticism, please.

#9, ejj. I agree that it will be difficult to implement this, but perhaps not quite as difficult as you imagine. The problem, in my view, is not so much land ownership, but political boldness. This plan easily could have been implemented for the new UC Merced campus, but wasn’t because even UC thought too conventionally. (I gave a talk to the UC Merced planning folks.) Some large developers in Northern California and some people planning an “eco-city” in China are interested in this; all of them could implement it, and if they don’t (and I suspect they won’t), it will be mainly from lack of vision.

#10-14, 16 Roger Pham’s idea. FWIW, I’m a long-time (formerly hard-core) cyclist myself, and enthusiastically support all plans to improve cycling and walking.

#15, al vin. Yes, of course, “greenfield” city designs are not new, but our particular transportation plan is. Also, keep in mind that this plan is intended primarily for suburbs in America, where there is no viable alternative to the automobile.

#17, Stan Peterson. We are not proposing starting over, we are proposing a new-town/infrastructure plan. We are proposing further segregation of road traffic.

#18,ToppaTom. I don’t understand the comment.

#19, Roger Pham. Well, obviously, you know my solution!

Hi Mark,
Thanks for the reply. You have a pretty neat and ingenious concept of urban planning that promotes efficiency, environmental conservation, and safety at the same time. The beauty of the light vehicles (LLM) is that they are very compact and require much smaller and cheaper overpasses than those designed to accomodate 18-wheelers. We would like to see closeup drawings of your concept in order to better appreciate the interaction between the two different transportation system.

With the bulk of personal transportation taken up by LLM using narrow roads, it is possible to drastically reduce the size of the FHV roads to make a city looks nicer. Small and light vehicles will drastically reduce the size of parking lots, further enhancing the aesthetic of a city that is now severely compromised due to the gross proliferation of asphalt and concrete.

@ToppaTom,
>>"In none of them, not one, was there a problem with fast, heavy vehicles present everywhere"

Yeah, tell that to the 40-50,000 people who died from traffic accidents yearly. Oh, so sorry, the deads can't hear you :(
Or you can say that to a hundred thousands of people who were severely injured from "fast and heavy vehicles present everywhere." Remember E=1/2MV^2. Doubling the traffic speed would result in quadrupling the energy at impact, four folds more severe the degree of injury, and four folds increase in braking distance, making accidents much harder to avoid.

>>"You would DOUBLE the number of thoroughfares"

But, remember that light vehicles are very compact, narrow, and traveling slowly, thus allowing much denser packing, resulting in saving in roadway spaces and parking spaces. The total result is a city with significantly less paved areas that contribute to heat-island effect in the summer that making the sweltering heat the more unbearable.