The Future

A possible future transport system

Introduction

This chapter deals with the future, and suggests three possible future transport systems, each with their own advantages and disadvantages. This chapter will hopefully lead others to their own ideas about where we should be going from the current situation. To the objection that today's cars are irreplacable, the response is that this was certainly true of horses before they were replaced by cars.

Part 1 - Starting with today's transport system

The current transport system in the UK is dominated by the car. Congestion is increasing in some parts of the country, and this is due to three main contributing factors: Congestion charging has been suggested, but it has serious failings, and other forms of car restraint are available. Junctions can be improved, in many cases by signalising them.

To deal with congestion, we need to examine how much space each person takes up whilst using various types of transport. This is shown in Table 1. Clearly from this perspective, the best form of transport is the bus, although buses are dirty and unsafe. The use of better power systems would reduce the pollution produced by buses, but would not address the safety issues.

Therefore bicycles are chosen as the base transport system. However, bicycles are too slow for longer journeys between towns and cities, and so a form of ex-urban transport be used on intercity routes. It might be thought that buses would be ideal for this where their disadvantages of pollution and safety are much less important. However, buses do not have enough flexibility of seating to accomodate pedestrians and cyclists. Moreover, whereas two buses could be scheduled so that the second one turns up a few moments after the first, allowing a quick interchange, there is no way of knowing when the cyclists will turn up. Consequently the ex-urban transport has to be responsive to the arrival of the cyclists. The best match is PRT, albeit with some changes from the usual technology.


Table 1: Typical PCU values for various vehicle types

Part 2 - Replacing the car

Figure 1 shows two typical car journeys between two places, one location in one town, and one location in another. We consider the case of adjacent towns since most ex-urban journeys are like this. Some people travel further every day, but these trips are much less frequent. Together with trips around town, the trips from one town to the adjacent town comprises almost all of the trips that are likely to be made by car. To provide a good alternative to the car for these trips is therefore a complete solution.

The car driver takes the quickest journey, and therefore drives via the dual carriageway. This involves driving along local routes, until the dual carriageway is reached. The dual carriageway is followed to the other town, where the process is repeated. The section along the dual carriageway is common to all vehicles travelling that way, whereas the sections in the towns are unique to each vehicle.


Figure 1: Typical car journey

This could be replaced by bicycles and PRT, as is shown in Figure 2. The bicycles handle the part of the route within each town, and the PRT provide an express service along a grade separated route. The bicycles provide for the unique routes within town, whereas the PRT provide for the common travel along the dual carriageway. The same route is provided, except at a much lower financial and congestion cost, because each section of the route is done using the most appropriate form of transport for that section.


Figure 2: The same journey by bicycles and PRT

Part 3 - What is required to make this happen

Some key components are required to make this vision real. Firstly, a new kind of bicycle will be required, which is faster, safer, and which provides better weather protection. A recumbent bicycle, as shown in Figure 3, addresses these issues. A speed limit of 20 mph would be set on the roads in the urban area, so that the cyclists could travel in the centre of their lane, where they could see properly and be seen by car drivers.


Figure 3: Recumbent bicycles

Additionally, some way needs to be found to get bicycles uphill in an efficient manner. It is possible to add an electric motor to a bicycle, although this increases the weight of the bicycle, and makes it less pleasant to pedal. A 4x4 vehicle could tow a trolley unit carrying cyclists and the bicycles to the top of the hill, with a scheduled arrival every 30 or 60 seconds in peak times. Alternatively, a bicycle lift could be provided, as is shown in Figure 4.


Figure 4: Bicycle lift, Trondheim - WM

The PRT is a variant on the traditional PRT form. The PRT pods are faster, travelling at about 40mph (by comparison, a conventional PRT has a cruise speed of about 20mph). The PRT pods would travel along the route, turn round at the other end, and then come back. This means that a typical distance between adjacent towns of 10 miles could be done in 15 minutes - it also means that the whole commute could be done in 30-40 minutes, which is about right. Additonally, the presence of large numbers of PRT pods means that one should be available when the cyclist arrives, minimising the wait time.

Part 4 - Elevated Roads

One of the simplest ways of increasing the capacity of the road system is to add an extra level of roadway above the existing ground-level roads. This effectively doubles the capacity of the road. An example, Hammersmith Flyover, is shown in Figure 5. The elevated deck has a length of 1 km, and provides two lanes in each direction. Because of the weight of the vehicles permitted to use these roads (in excess of 40 tons weight for the largest articulated lorries) the elevated road is made out of substantial quantities of reinforced concrete. The elevation of the roadway spreads traffic noise further than from the ground-level roads which are shielded by the adjacent buildings. The substantial nature of the elevated structure makes it expensive.


Figure 5: Hammersmith Flyover

However, if the elevated roadway was only for bicycles, weighing only a few tens of kilograms each, a new type of structure is created. Due to the low weight of vehicles, the roadway can be much more slender, with narrower supporting columns. The structure is therefore low cost. Also, because bicycles are quiet, the problem of noise being radiated from the elevated road is eliminated.

How wide do the elevated roadways need to be? A 3.5m wide lane of traffic carrying cars will have a saturation (maximum) flow of 2000 cars/pcus per hour - more or less. Each bicycle only occupies 0.2 pcu of road space, so that 10,000 bicycles carrying one or two people can pass down each lane. So one lane in each direction can pass more cars per hour than a motorway. Therefore two lanes, with a width of 3.5m each is proposed.

These elevated roads would be used to connect areas of a large city, at a speed of 20mph. The roads would be simple point-to-point links. Due to the delays imposed at ground level by junctions, in a city like London a speed of 12mph is quite typical. At 20mph the bicycles along the elevated roads would be about twice as fast as the cars at ground level.

One further improvement is dynamic lane sizing. If the two lanes are not seperated by a barrier, lane markings can be provided by LED strips running along the road deck. A computer can watch the cyclists going past, counting them using diamond shaped loops embedded in the road, and if one direction needs more capacity the centreline can be moved by switching some lights off and some lights on. This is shown in Figure 6. The loops detect more cyclists going north than going south. The LEDs showing the centreline are moved across as a response, giving more capacity for the northbound traffic.


Figure 6: Dynamic lane markings

Part 5 - Some Other Unusual Technologies

Some of the other technologies of the future are likely to be from the past. This is because those technologies still work, but were abandoned because they didn't fit into the plans of the past, some of which have now been superceded.

One important approach today is pedestrianisation, where the assumption that cars improved the street-life on a shopping street has now been rejected. The shopping street is usually repaved, and is blocked to all or most traffic. Shoppers arriving by car must park further away from the destination and walk the rest of the way.

The main limitation on this approach is how far car drivers are prepared to walk before they give up and shop elsewhere.

One solution is horse trams. They were originally replaced by electric trams, which were subsequently replaced by buses for two reasons - the trams were too slow, and the horses dropped horse dung on the streets. The second problem can be fixed by putting an apron behind the horse, an approach which is often used today. The slow speed of the horse tram is not a problem if the tram is expected to cover a short distance across a pedestrian area, indeed it is more compatible with the pedestrian nature of the area. It would also be a tourist attraction in its own right.


Figure 7: Horse tram, Linz Railway, Austria - WM

Another area of growth is the increased use of air travel for commuting. It is possible to bypass queues of traffic using helicopters. However, if there is space for helicopters, there will be space for biplanes.

Biplanes, another technology which if officially obsolete, has many advantages over helicopters, including better fuel efficiency, reduced emissions, reduced cost, and reduced noise. By having two wings, the necessary wing span is reduced. Although other aircraft are faster, a biplane can travel at low level, and much faster than a car, whilst still being easy to fly. Biplanes can take off over short lengths of runway, which as is shown in Figure 8, need not be laid to tarmac.


Figure 8: Stearman biplane - WM/Arpingstone