Sky-Cycle-Ways, Elevated bike lanes

How can you possibly suggest that cycling might be faster than driving or taking a bus or a train ?

This is very much the case of the turtle and the hare. In this case the hare is the car, it can be very fast, how ever the car has to deal with traffic lights and intersections. The car can be quite fast between junctions but a the junctions it's waiting. It also takes time to accelerate to the maximum legal speed, people tend to let the car in front take off before moving them selves. All this added together makes the average speed in urban/sub urban driving low. Next time you go to work try this - get in your car and make a note of the distance on the pedometer and the time. When you arrive and have parked make find out how far your have traveled and how long it took. Divide the distance (in miles) by the time it took to travel ( in miles per hour ) and you might find the average speed is a lot less than the speed you might think you where actually moving at.[More details]

The logic is the same for trains, the top theoretical speed is higher than the actual speed. Unlike a car you have to add in transfer times, that is time spent waiting on a platform when you transfer from a bus to a train or a train to another train.

[ If you want to find this out your self click here CALCULATOR ]

For trains we solve the stop problem with 'express' trains, the stop less and so can go much faster. For cars we solve this problem with highways/freeways/motorways/autobarns. The main flow of traffic is never interrupted there are no stops and so the average distance between stops is higher.

In town bikes suffer the same limitations as cars - they have to wait a junctions and lights. For the humble cyclist this is worse than for a car the cyclist has to put more personal energy into accelerating. The stop/go stop/go nature of in town movement adds to the lower average speed of the bike. This is partly reversed by the bikes ability to weave to the front of the queue at the lights. Traditional cycle lanes don't try to solve the problem of stopping at traffic lights. What would travel be like if we had a cycling version of freeway or express lanes' ?

The overhead cycle lane is just such an freeway for bikes. If you have traveled on one of the 'rail to trail' cycle ways you might be quietly surprised by how far you can travel so fast The rail to trail routes tend to have a very low gradient on them, this again helps by reducing the effort to travel. Naturally any long, segregated,junction less and preferably flat cycle path would be sufficient to gain high speed bike travel. For example a underground system might be able to make the same gains in speed, an old underground subterranean rail route would work. For practical reasons I think it would be cheaper to construct flat overhead bike paths than dig new tunnels. If a city had an abandoned network of long subterranean passages it might consider using them in a cycle network, the gains in time should match those of the over head overhead bike paths.

Again the same average speed logic would work for a cycle path which was on the surface and followed abandoned rail routes into the city center. Most rails to trails routes tend to be in rural areas, if an urban rail line was available for conversion then the higher average speed on uninterrupted routes would make up for the average lower speed of the bike. Both the underground and rails to trails option both suffer from the reutilization problem. We build them where we can, not because there is a demand. Imagine what would happen if we built free ways because there was some suitable space, not because there was some quantifiable demand to use the route ? The overhead system works because it can 'share' the roads and be built in response to need.

If you examine the PRT (Personal Rail Transport ) concepts, they are trying to achieve for monorails what a freeway achieves for the car or the an express does for a train. By not stopping for stations and not stopping to change routes a slower PRT can achieve higher station to station transfer times.

To conclude

By having a 'freeway' for bikes would reduce the average time for uninterrupted travel between two points to near or below those of cars and trains. This average speed logic only works over shorter distances, while you might out pace a car traveling 30 miles in heavy congestion I'm sure the cyclist would become exhausted at some point. The informed reader might have realized that nearly 50% of journeys are less than 3-4 miles which in the right urban conditions (lots of traffic lights) give a uninterrupted cycle path the advantage.

 

 

 

 

 

Addendum

Notice also that like a car freeway system the over head cycle paths don't have to be monolithic but hierarchal. We don't all drive to work exclusively on freeways even though they might make up 80% of the distance traveled. We don't need a 100% complete network of overhead cycle lanes over every road, we only have to provide well chosen arterial routes and use the roads and ground level cycle paths to reach the final destinations.

Naturally the argument presented is that of a pure system. There is no fundamental reason not to combine systems. For example a train might be used to travel a longer distance with few stops. The skyway network might be then used to reach out from the station to the surrounding urban context. By eliminating the walk to the station

 

Notes on calculating speed

If you would like more information on the average speed for light rail calculation you might want to see the fun calculation spreadsheet by Douglas J. Malewicki, AeroVisions, Inc. at [this external link].

 

[ HOME ]