Sky-Cycle-Ways, Elevated bike lanes

Going the distance - (relatively)Long distance cycling

On of the limitations of the elevated cycle lane concept is the limitation of distance. Cars and Mass Transit can commute 45 miles in ideal conditions. The philosophy of the elevated cycle lane concept is that 48% of journeys are less than 3 miles, which permits the system to help reduce fuel consumption.

The main elevated cycle lane concept is simple, cheap, well understood and practical. This section project forwards and discusses some potential solutions to long distance travel and elevated cycle lanes.

A good friend - Working with rail and bus

Unlike many forms of transport elevated cycle lanes are friendly to most other forms of transport. Take mass transit like rail, one of the problems with a highly car dependent suburban structures is that they make mass transit services very hard to deliver. The general radius of 'collection' for a rail station is about 0.4 miles. Less than 2% of the population of Atlanta for example is within a 0.4 mile walk to a rail station. a suburban context this returns a small number of potential houses per station. In many outer suburban contexts this forces mass transit out. Elevated cycle lanes offer the ability to help concentrate passengers. Like Park-and-ride and kiss-and-ride we use one form of transport to get to another. With this concept it is possible to run more trains per hour and so reach the kinds of mean-time-between-trains which make convenient transportation which is competitive with a car.

A railway station (gray circle) and it's catchment area (light gray ), introducing continuous cycle ways (blue lines) safely increases the catchment area.

Elevated cycle lanes provide a unique advantage over park-and-ride concepts. The bike can remain with you on the train. With park-and-ride the destination station must be with in 0.4 miles on average walk of the place of work. With a elevated cycle network you get a much larger radius of destination. For cities with tight cores this might not be a problem, for cities which are more polycentric or just plain sprawled this could be a way of expanding the effective collection radius for a train station.

The basic core of the elevated cycle network is completely known technology, we build cycle bridges, escerlators. There are a few unknowns which a test system would help to clarify, 50% of people say they would cycle to work if a suitable safe and convenient network. If such a system did exist then how many people would decide to regularly travel. To meet the objective of reducing congestion we only need a reduction trips by about 1-8%. The reduction is very dependent on the individual city and the specific conditions involved. The larger percentage of the population which switches the better - it reduces oil imports, saves resources for future generations, cuts back on local heat island effects, reduces local pollution and reduces congestions. An experimental system would help to clarify the planning factors would help. Unlike a PRT system or a monorail, nothing new needs to be built, the elevated cycle way can be built from 'off the self' parts. This is one of the great advantages of an elevated cycle network - it's known technology and so reduces the possibility of cost over runs.

What if we can use technology we don't have much experience with ? The rest of these concepts include notions which may or many not work. They are purely optional and there would failure have zero effect on the elevated cycle way concept so far. There success would expand the effective size of the network but to how far it is as yet unclear. With these provisos lets look at some of the first possibilities.

Cycling with assistance

Is it possible to extend the range of a elevated cycle network. Is is possible to do something to boast the range an average cyclist might have by some means. If it was we could line some of the main arterials, or longer stretches of abandoned rail track with 'long distance elevated cycle lanes'. Current cycle trails can stretch up to 225 miles ( Rails-To-Trails ) on a normal bike this would take 12.8 hours. Clearly too long for the average commute. If we can increase the natural average speed, or reduce the effort to maintain a long distance speed then we can increase the effective radius above the 6.75 miles ( 13.5 miles per hour for 30mins ) which the skyway system is currently planned around.

With the wind to your back

When cycling the power the cyclist expends goes up with the cube of the velocity (for more information). This means a number of things, cycling at 10 miles per hour with a 10 mile per hour head wind is like cycling at 20 miles per hour and requires 4 times the amount of energy which traveling with out the head wind would require. To facilitate optimal speeds the skyway system acts as a wind baffle. What would happen if we use fans to push energy from behind ?

The skyway system generally consist of one tube going in each direction. This lets us push the wind in one direction. By pushing air at 10 miles per hour, a cyclist pedaling at 17 miles per hour would feel like they where cycling at 7 miles per hour. If we could push the air into the tube at 15 miles per hour then a cyclist would be traveling at 32 miles and hour expending the energy of 17 miles per hour.

Notice this is only possible with an enclosed track. The energy require to push the air down the tube would be proportional to the frontal area of the tube its self. By having a system with such a wind to your back would permit people to travel for further or to travel faster. This is not an entirely new idea in 1899 a moving windshield let a man cycle at 60 miles per hour. More details

Follow the CalcsWeb has an intreasting calculation showing that stopping and starting at each street intersection moves the power consumed to increase by a factor of 5.

Under your feet

An alternative to a wind to your back is one possibility the other is to use a moving walk way or travel-at-or this is a well known technology ( here ). By using moving walkways at intervals the tube would lift the cyclists up followed by longer slopes down a gentle slope.

Pulling Upward and Onward

Another system under consideration for the entry to the cycle lanes would be a system derived from a ski lift like arrangement.

The basic mode of a wire being pulled by an electric motor has been used since Victorian times and has quite a long,reliable and inexpensive history. Test would have to be performed on safety but it might be cheaper to have ski lift like systems at stations.

Once on the system a similar horizontal system might be used to pull cyclists along on longer stretches. This concept has been suggested by James Cline, after getting on to the tube system the cyclist accelerates to match the speed of the belt. Perhaps the belt runs along the side of the tube, the cyclist grabs a handle which then provides tug to pull him or her along. What is unclear is how fast the belt could safely run and how long a belt could be. Perhaps a shorter belt could be organized like the lengths of travelator, pulling cyclists up a slope allowing them to roll down a longer gradient on the other side. The elevated cycle concept would make this a very feasible concept. Where as it might be difficult to run the belt running along a street, the space of the elevated skyway makes it possible to install such a system - if its shown to be safe to install.





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