Sky-Cycle-Ways, Elevated bike lanes

This is the outline for a proposal for a new kind of elevated cycle way. The sky cycle way is an elevated cycle network which reduces time for travel for cyclists. This network turns any city into a flat Amsterdam or Cambridge. I believe this is the lowest cost for installation for any personal rapid transit system. By expanding on the understanding of the design and construction of monorails and other elevated transportation methods.

An imaginary ride

In your mind you leave your house to ride to your office. You leave your house by bike, you cycle either on the road, the sidewalk or on a separate bike path or trail to your nearest 'station'.

The station is a simple affair, perhaps it includes some kind of smart card to help pay for the network and raise money for more skylanes or perhaps it is just sponsored by the city to reduce congestion for those who live much further out. Overhead a light network of steel lifts a tube high into the air. From the ground you are pulled up by a skilift or escalator to the operating level of the skyway just above the level of the traffic.

The skyway is a long cycle lane. It's naturally ventilated but enclosed, in the summer the roof shades you from the worst heat. In the winter the glass helps keep the warmth in. In the fall the glass keeps the winds from slowing you down. In the spring the roof keeps the rain off your back. The perfect cycle floor, always free of glass and debris, always as level as the best technology can make it means a fast plesant ride in. You can ride slowly conserving energy on the way in, passed by more enthusiastic commuters who have a shower waiting at the far end. You normally coast most of the way to work, the legs of the sykway change hight flattening out the changes in ground level. Your policy is to ride to work but on the way home the skyway becomes your gym.

Looking to your left, out of the window you see down to the street level. The sykway is deliberatly designed to make it hard to look directly down, this helps nevious riders who might have problems being this high off the ground. The skyway it's self casts a thin shadow down the street below, on the street you see traffic ideling at one red light after another. While the cars might be fast between juntions, you never have to wait at a junction and so quickly loose the car that passed you as you entered the network. Sometimes the windows are frosted on one side or another, this was part of the agreement not to 'peek' into the adjacent buildings.

Above you there is the latice of the ceiling. There are lights at intervals which provide lighting at night. Between then are the security cameras which guide the security patrols who keep the cycle ways safe. So safe infact that some parents are happy to bring their children to the nearest skyway station, and leave them to cycle to the skyway station next to their childs school. Occasionally you see an east/west cycle lane which is a few meters/feet higher than the north south lane you are using. This vertial seperation of lines means that you never have to stop at a junction within the cycle network. You have a green light from one end to another.

At intervals you pass the 'stations'. These stations are where people might enter or exit the raised systems. Sometime the stations lead directly into the first or second floor of a building, meaning you can travel 90% of you jounrey in the dry even in the worst weather the winter can muster. Some of the more central stations have more facilites such as secure parking and showers. These are used to help supplement the income of the skyway system and pay for it's maintance and expansion. Between the stations there are occasional emergancy exits. The whole skyway system is a white modular steel construction. If one section is damaged it might be lifted out of place one night and replaced with another section. At intervals there are 'spliters' which indicate the potential for future expansion. Some times when building work is happening the whole local network is rebuilt changeing routes around the blockage. The skyway network is flat, so deviations from the shortest route are not really an inconveniance.

The skyway system is laided out like a system of rail routes. It's time for you to change from the north south blue route to the east west green route. This involves a change of levels which is facilited by a flattened escalator which lifts cyclists betwen levels. Even when the escalator is not working the system keeps working - you just have to cycle up the slope.

You drift almost silently though the urban landscape which has appeard around the skyway as you get closer to town. Your station appears, the cycle way is pretty crowed now so you check behind before pulling off on to the exit ramp. The exit ramp leads down and a n incline, unlike the hardfloor all over the skyways this is made of soft rubber. The design is such that you can free wheel down the ramp but your speed at the bottom is not that great. This helps prevent collisions with both traffic and pedestrians at the bottom. It's almost a shock to appear on the ground with the noise and grime of the city. If this was a rail system you would now have a long walk to your office. As you are on your bike you can use it to reach your destination quickly and more importantly your not late for your early morning meeting.

When the skylanes first appeared, your choice at the exit from stations was the road, or to walk on the sidewalk. As the number of cyclists started to increase a sporadic network of surface cycle lanes emerged over the years. The local shops also joined in this change by installing bike racks outside there shops to induce passing trade to stop. Much of your journey from the station to your office is now on dedicated green lanes. The number of cyclists is now so large that drivers are aware of and sensitive to them on the streets. This help keeps the number of accidents on the streets to the same number as those between vehicals and pedestrians. As you go down the street you hardly notice the thin skyway over head. The skyways come in a number of modular sizes, narrower streets support oneway single lane skyways, larger streets support larger two way units. Unlike the Chicago loop the street remains relatively open, the cycleway introduces pratically no noise (unlike most overhead rail and monorail designs ), the cyclepath also does not transmit 'shudder' though the foundations.

The skyway network is far more reliable than the congested taffic includeing the bus network. Your at work on time, now you don't have to find a parking place for your car anymore you've managed to leave home later and arrive at work earlyer. The office converted a parking space to a shelterd cycle rack. You lock up your bike and go to work.


The problem

You can define the problem in many ways. You might look at this as a long term environmental problem. Can America afford the long term dependence upon oil ? Something which will inevitably run out ? Oil has become the key factor in the structure of cities such as Los Angels and Atlanta ( too name two). If all the alternatives to oil cost more then how is America expected to make a transition to this future economy ?

Alternatively look at the air quality of a City like Atlanta (here for PDF),In 1990 tons of nitrogen dioxide where dumped into the atmosphere by the vehicles per day. The current official target is to reduce this to 225 tons by 2004 and at the same time make Atlanta more mobile. If Atlanta means to grow this means having more people making more journeys and at the same time keeping the charge to the economy of Atlanta to the same or lesser value.

If you believe the concept of Air Quality is irrelevant then perhaps you should answer how America can afford to waste millions of dollars being stuck in traffic ? When you get to your destination can you afford the cost of the parking ?

Some new solutions

Historically the solution to transit was the introduction of so called Mass Transit. This involves pulling people together in buses, trains or Trams, this gain in by the economies of scale are frequently at cost to the convenience of the individual - they have to travel to the bus stop/station and board vehicles at fixed schedules times. Even High Occupancy Vehicle(HOV) or car pooling has had a comparatively poor uptake ( Atlanta's HOV lanes are relatively free).

One of the most recent developments has been the concept of Personal Rapid Transit. ( see for a definitive list on PTR and or for an assortment of alternative proposals ). The basic notion is to make a train as personal as a car. You dial a 2 or 4 seater vehicle, it arrives and takes you directly to your destination. One possible summation of PTR transportation system is.

  • Considerable time can be saved if the train does not stop from the start to the end of a trip.
  • Journey times can be reduced by automatic steering, this can me no stopping at junctions or the ability to use the faster reactions of the computer to run vehicles closer together.
  • The introduction of a elevated ( or lowered ) system is in effect potentially doubling the number of streets available for movement in a city without doubling the size of the city.
  • Monorail solutions don't shadow the street as badly as full elevated rain ( think about Chicago near the loop).
  • Personal Rapid Transit (PTR) systems don't use massive trains so reducing the size of the track and so lowering the installation costs compared to an elevated route.
  • Any raised system has less expense over ground rights.
  • Any raised system can be run with out blocking the current road network - unlike a ground based light rail system or introduction of large numbers of busses.

I'm not going to jump into a critique of PTR systems - I think if skillfully introduced they gain from the same kinds of networking benefits the Internet or the phone system does. By having a larger network the potential trips grows at the square of the number of stations. PTR systems also have the possibility of lowering costs, buy removing the need to have 'accompanied' cargo. If every shop and supply center could be linked by an automated cargo transportation system then potentially the delivery of objects would drop.

If I might I would like to look beyond the basic needs of transportation and add in an extra component. Another problem which is growing across American and is quite prevalent in Atlanta is obesity. Obesity according to the Surgeon General quickly becoming the number one killer in America. If you look at the Center For Disease Control statistics, heart disease is the number on killer on the loose in Atlanta and Georgia.

Principally one of the problems with any mass transit system is that the less dense the area gets the harder it is for public transport to provide a decent level of service. Brian Richards suggests a cut off point beneath which it is impossible to provide a bus service. In the case of light rail systems like MARTA, the problem is getting people to the stations from the region around the station. One solution park and ride means getting the car out to ride to the station, while this expands the area which fan 'feed' a train station. It also means that the car is being used at the worst part of it's pollution cycle - during the first 5 minutes on when the cold engine is at it's most in efficient.

Sky Cycle network

I would like to propose that a solution which has not received enough consideration is that of a integrated cycle network which has a component which consists of a raised cycle ride ways. This elevated cycle path functions like a freeway/highway/motorway for cars. My argument is that raised cycle paths have the the visual impact of a monorail. The argument is that over head cycle ways should be considered Personal Transit System which uses bicycles as the 'carriage'.

The central logic behind a fully cycle network is to produce the cheapest possible raised transportation network. With monorails the way to do this is to reduce the amount of metal or concrete in the air. The less material in the air, the further legs can be spaced, and the more insubstantial each leg becomes. The less matter in the air the less right to light issues ( read costs ) are incurred to the project.

There have been some suggestions for a mixing of suspended bicycle ( ), I would like to go one stage further and suggest a fully raised cycle network. This is fine ( I could imagine a really nice network like this for a theme park it would be great). For an urban commuter context I would argue that keeping the bikes attached to the traks looses the natural efficeny gained by having a form of transport available to get you to the station.The logic behind this is to gain a larger buffer around the stations which can extend the collection area for the network.

Secondly one of the advances of PTR are that smaller vehicles generate less nose and intrusion. In both cases it is necessary to reduce the weight of the vehicle in relationship to the weight of the passengers. One of the few cases where the vehicle weight is less than that of the passenger is the case of the bicycle. This should push the system to be it's most efficient and there for most cost effective way of moving people from the road network. Remember I am not suggesting we remove all cars from and Atlanta and replacing them with bikes, if I was then the elevated component would not be needed. Instead I am suggesting we can reduce travel times for those relatively close to their work locations ( within 5 to 10 miles ). This removes people from the roads completely and so frees up space to so help reduce congestion for those who live further out. Notice like a monorail,PTR or the underground MARTA system this does not involve interrupting the road network or have any other service which is competing

Ok that's cycle network as Personal Rapid Transit system. Now lets look at the whole thing from the traditional cycle network. When surveys are done the list of reasons people don't cycle to work is something like

  1. Danger - Cycling on the streets competing with cars is perceived to be a dangerous affair.
  2. Exposure - Cycling in the open exposes the passengers to wind, rain and the heat of the hot sun.
  3. Work Load - Cycle networks are much more popular in relatively flat cities like Amsterdam, or Cambridge. Hilly cities have problems.

Danger is the first and most pressing problem. If you think this is a concern then ask your self one question. Are you happy letting children ride on the streets ? I think the test for a design safety must be are you happy children cycling ?

In fact there are situations when people are happy cycling, when they are using a segregated cycle road. Fitting a segregated cycle network back into a city is a very difficult thing to do. If it is done then the cycle routes are chosen and a available basis rather then the kinds of engineering methods used by planners for roads. Like a light rail network working at at grade network into an existing city plan means interrupting both the road and the light rail network to the detriment of both.

For the same logic that drives the a metro system underground or above ground ( in the case of a Monorail). I propose we must make available in addition to a well integrated, separated cycle network.

A raised cycle network, the logic is similar to the existence of a freeway network for cars. While a cycle network will work at a different scale, the underlying logic is the same, introduce long runs of uninterrupted motion. This reduces two things, firstly like any PTR, reducing stops between the origin and destination reduces travel time or increases average speed. Secondly which is an added benefit to a cycle network, not stopping and starting means the amount of energy necessary to go from origin to destination is reduced.






info on oil running out. ( anti rail lobby )