Transport, congestion and pollution - the way forward
Buses are much more efficient in terms of road space and energy per passenger than cars. Zero emission electric buses take this advantage to the ultimate. For example, 1 vehicle in 20 travelling round Parliament Square is a bus and yet they carry 50% of the people. To encourage motorists to use buses more and drive less, new designs of buses need to provide the facilities people have got used to in their cars and avoid the pollution cars create. State-of-the-art electric buses will be a fundamental step in achieving a smooth, clean and quiet traveling experience.
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It is now recognised almost universally that the two issues above represent major problems in the London area. In 1999 more people died from air pollution in London than from road traffic accidents. As with many other complex issues, the two are very much interrelated. Cars and other internal combustion engined vehicles represent a major source of particulate pollution into the atmosphere at street level as well as producing high levels of "greenhouse" gases such as carbon dioxide.
The Present Situation
Whilst the proportion of public to private transport for radial journeys into and out from central London in the peak especially, is very high, the amount of private car journeys still clogs the road system and produces slow moving "stop-start" traffic. This maximises pollution from the vehicles and delays buses using the same infrastructure. In the outer suburbs and especially for orbital journeys, the car is the majority transport mode even in the peak. This means that many outer roads are at least as congested or more than many inner roads. There is the same resultant pollution and decrease in bus speed and reliability.
Whilst almost everyone agrees about the problem, few car users wish to desert their vehicles to travel on the existing bus network. The perception of buses is that of a transport system that is slow, overcrowded, dirty, noisy unreliable and late with poor customer interface. This is not only perception. Because of traffic levels and staffing problems, bus services have a cancellation level which is too high. The old joke that "no buses come along for ages and then three come together" is repeated many times in practice, because of the traffic congestion, making a mockery of published intervals of service shown on the timetables. This combined with cancellation levels, causes bus to run with crush loads, far greater than would be necessary if the published frequency were maintained. It is frequent for bus services to be timetabled to take an hour in the peak to go ten kilometres (seven miles per hour). Often even this speed is not achieved in practice. Buses can be seen (correctly) as themselves polluters of the atmosphere. Whilst the total pollution from many people in one bus is clearly less than that from many cars, it is easy for those who wish to do so, to argue that this is only a "matter of degree" and that "they might change to public transport if it caused no pollution itself".
Before considering options, it is necessary to know which options are available and the intrinsic characteristics of each.
This covers a wide range and is exemplified by the use of shorter formations of lighter vehicles operating around sharper curves and steeper gradients than heavy rail, generally at lower speeds and with stops much closer together. Docklands Light Railway exemplifies a "heavy" version of Light rail with high level stations and full signalling. Other Light Rail systems are much "lighter". Croydon Tramlink for instance is operated on a "drive on sight" principle without normal rail signalling. The platforms are low and stops are relatively close together. Where the track is reserved for light rail use only, speed can be fairly high. 80 Km/hour (50 m.p.h.) is quite normal. Modern Light Rail systems are characterised by level access between platform and vehicle. Ticketing systems vary between machines at stops (Croydon, Manchester etc. in UK), machines on the vehicles (none in UK but many in other world cities) and conductor issuing (Sheffield in UK). Light Rail systems can operate on tracks reserved for their exclusive use or using grooved rails set in the normal carriageway ("street running"). Manchester, Sheffield, Birmingham and Croydon systems all have both types of operation although the proportion between them varies considerably. Manchester, Birmingham and Croydon have a very high percentage of reserved track operation whilst Sheffield has a much higher proportion of street running. As light rail vehicles are permitted to be physically much larger (both length and width) than road vehicles, the capacity of light rail vehicles even with street running can be as high as 250. This implies that peak flows up to around 8,000 passengers per hour can be carried by light rail. Although theoretically, traction can be other modes, the vast majority of light rail systems (including all the present UK ones) are electrically operated. The vehicles on the lighter forms of light rail are often referred to as "trams" irrespective of whether any street running is involved. Costs of Light Rail vary enormously. Where previous old railway alignments have been used for conversion to light rail reserved track, the cost is much less than street running sections. Whilst the former may cost around �4,000,000 per kilometre, the latter can cost up to �20,000,000 per kilometre (recent street running construction in Manchester). Light Rail has nonetheless proved very attractive giving modal change from car of around 20% (Sheffield). In London, the figures thus far, indicate that Croydon Tramlink will also achieve very high modal change from car.
Conventional Diesel Bus
It follows that if nothing is done to the current bus network, that which has been happening is likely to continue. A spiral of decline will ensue, causing more journeys to be made by car, increasing traffic, reducing reliability and increasing costs of operation of buses. Buses can be made more attractive, by increasing passenger information, giving greater traffic priorities, and purchasing newer and more attractive vehicles. The costs of what is done obviously varies greatly in accordance with the scale of improvements made but it is possible to spend up to nearly a million pounds per kilometre on bus route improvements. Despite this, evidence from Birmingham has shown that modal change is of a very much lower order than light rail schemes. Even when the most possible has been done to improve the image of the bus, there is still something missing to attract large numbers of people back out of their cars.
It follows from what has been stated above, that people will leave their car and transfer to more attractive forms of electric transport. Unfortunately it also follows that the costs of electric rail solutions are high. They can only be justified on certain corridors with very high passenger flows. They do not represent an option that can ever be viable over a large network such as that currently operated by diesel buses around London. Diesel bus options do not achieve the desired modal change and thus the quantum reduction in pollution that is required. Buses continue to contribute to on street pollution of both particulates and gases. They do not initiate a virtuous circle of improvement and modal change. What then can be done about transforming those parts of the bus network for which the rail option is too expensive?.
Trolleyways are a total journey concept, but using tried and tested technology. The individual elements of the concept are not new, but the combination of them all represents a new concept in high quality urban transportation. The vehicles are Trolleybuses. These are high quality, comfortable vehicles with a capacity of 120 or more. They are electric but use conventional tarmac roads and are steered like conventional buses (automatic guidance systems can be used but are only really necessary in certain sensitive areas such as pedestrian-only areas). They collect their power from overhead wires in the same manner as light rail vehicles such as Croydon Tramlink etc. Where traffic flows freely, no special alterations to the road infrastructure are required. It is necessary to segregate the Trolleybuses from other road traffic at congestion points, and to give preference to them at road junctions, traffic lights etc. All stops are raised, using Kassel Kerbs, to give an area where the Trolleybus driver can stop their vehicle with level access from the kerb to the vehicle. This gives the same level access as light rail systems, such as Croydon Tramlink, rather than the ramps etc. required for "low floor" buses. Such stops are arranged so that the trolley vehicle can immediately accelerate away from the stop without need of waiting to pull back into the other traffic. Pre-paid tickets (seasons, travelcards etc.) would be encouraged but cash fares would be collected by a customer service person, similar to the conductors on Sheffield trams. The costs of construction of such Trolleyways would vary dependent on the precise characteristics of the roads used, but could be around �1,000,000 per Kilometre. The preference over other traffic combined with the rapid acceleration of high power electric vehicles and the removal of the need for the driver to check and issue tickets would substantially reduce journey times and make them more consistent. As a result not only would journeys become much more attractive to current car users but less Trolleybuses would be needed to operate a given flow along a route compared to conventional diesel buses. The vehicles would be zero polluting at street level, exactly the same as light rail. Analysis of the various costs indicate that for routes with peak flows of around 1000 to 7000 passengers per hour, the provision of Trolleyways is very cost effective. The infrastructure costs could be little more than the cost of improvements made to a conventional diesel bus option and could be recouped over the lifetime of the system. Yet, unlike the conventional diesel bus, the Trolleyway offers quiet, speedy electric transport. These are almost certainly the missing factors that transform the image of the network in the eyes of the passengers. Trolleyways thus represent a way of converting a large part of the current bus network into a modern high quality public transport system. The adoption of Trolleyways would certainly result in a higher modal change than any diesel bus operation and could give levels close to light rail but at a fraction of the cost. They could break the vicious circle of public transport decline and start a virtuous circle of improved public transport and lessening car usage across a very large network, resulting in much lower levels of pollution across the whole of London.
Gordon Mackley. The Electric Tbus Group