Select Committee on Environment, Transport and Regional Affairs Appendices to the Minutes of Evidence

Annex 4

Financial, Operational and Demand Comparison of Light Rail, Guided Bus, Busways and Bus Lanes


  The purpose of this study was primarily to evaluate the experience of existing light rail, guided bus, busway, and bus lane systems to current plans for expanding the role of public transport generally. The evaluation covers technical and financial aspects, together with results of surveys (including new ones carried out for the project) on the attitudes and judgements of passengers and car users. In the final section of this summary we outline a policy evaluation based on the study.

Existing and proposed systems

  When studying existing and proposed systems it is evident that light rail was and remains the mode in which are invested the greatest aspirations for an expanding role for public transport, especially in Europe, but also in the US. Bus lanes are rarely provided with the extensive network of priorities that would be necessary for them to fulfil their potential, except in the centres of some capitals. So far there is no city in the world which has implemented a full guided bus network, so the experience is meagre. It is a matter of concern, for British current thinking, that apart from Leeds, none of those other few cities which built guided busways, have expanded them further. Busways, however, have been built in a number of North American cities, also in Brazil and Japan: in two cases which we visited, it was clear that an important consideration was the availability of existing rail, tram or road corridors suitable for building busways. There are numerous proposals for new busway sections, especially in the US and Australia. In Europe there are few sections of busways, mostly constrained by unavailability of suitable space.

Technical aspects

  In terms of the corridor widths needed, light rail requires least space and busways most. Bus lanes and guided busways are in between. In terms of passenger capacity, normally light rail can transport more passengers than standard buses. However, the example of Ottawa shows that the same number of passengers can be transported as with light rail. Particularly interesting is the new generation of guided buses, for example the TVR which has about the same passenger capacity as a light rail vehicle.

  Speed is mainly influenced not by the inherent running space in free flow conditions, but also by stop density, and existing light rail corridors usually have many more stops than busways. As a result, buses running on busways are the fastest, followed by light rail where it has right of way. Where light rail shares space with car traffic, it tends to run faster than buses in similar conditions.

  Noise and pollution considerations favour light rail, but innovations in the diesel technology will provide zero emission buses. Noise is a problem with older vehicles, whether rail or bus.

  Running comfort for passengers is best with light rail but can also be good with buses.

  Overall, with regard to the technical aspects, modern light rail vehicles operating on their own corridor will rank slightly higher than buses in terms of space, speed, capacity, comfort, pollution and noise although buses could do equally well in terms of capacity and speed, and modern buses also on pollution.


  Infrastructure cost per kilometre varies substantially for all modes, depending on conditions and terrain. The most costly is, of course, light rail operating in tunnels, and the cheapest by far are bus lanes on existing road networks. In similar conditions, the infrastructure costs for light rail, busways and guided buses are closer together than has often been assumed. Light rail and busways are very similar in cost. Guided busways are generally slightly cheaper: We do have some examples where guided busways are very much cheaper, but it would be overoptimistic to assume this will always apply.

  There are clear differences between the vehicle costs, light rail being by far the most expensive, but also having the longest life expectancy. However, the newly manufactured guided buses, the TVR, Translohr show similar costs to a light rail vehicle. Overall vehicle costs for buses are much cheaper than light rail.

  For operating costs, some available examples for Germany and the US indicate light rail as slightly cheaper than buses, on a lifetime basis for similar levels of service. However the examples from Pittsburgh and Ottawa show that the operating costs per passenger km are about four pence cheaper for buses than for light rail, even if the average loading factor for Pittsburgh is included. This implies that the loading factor is decisive and that light rail could only be cheaper than buses if it is running at or near full capacity. The difference in the cost per passenger km between the two New World cities reveals that apart from the loading factor the difference in the labour cost of bus drivers can be crucial.

—complementary measures

  A number of complementary measures are easier to implement with light rail than with buses, for instance pedestrianisation, but complementary measures are vitally important to all public transport modes and may hold the key to the success of the public transport system as a whole. Conversely, investing in new and expensive public transport systems without planning at the same time to implement strong complementary measures will certainly reduce the value of the investment and may even lead to a waste of money.

—passenger gains and the level of transfer between car users and public transport

  Newly constructed public transport infrastructure does in most cases generate significant growth in the number of passengers—experience varies from a few per cent up to 50 per cent or more. There appears to be a tendency that European cities which operate significant light rail networks have gained more public transport passengers over the 10 year period 1986-96 than cities which rely only on buses. The reasons are not clear. It may well be that those cities which operate light rail have a tendency to implement more effective car restraining measures, partly because light rail can help to provide the political consensus to adopt more radical approach to car restraint than bus-based systems have allowed. Effective complementary measures also influence the growth in the number of passengers. However a few US cities experienced a decline in the number of light rail passengers between 1990-95.

  Yet the fact remains that in the majority of cases most of the growth in public transport use has resulted from a greater use by existing passengers, rather than making substantial inroads into car use. Research suggests that for light rail, transfer figures of more than 20 per cent are very much the exception and not the norm. Transfer from car use to guided buses, buses on busways or buses on bus lanes appear to be lower, except for Dublin where the percentage was 16 per cent. We do, however, have far less research on bus-related improvements. Dublin is exceptional but it shows what can be achieved if traffic conditions for car users are very bad. No information on transfer from car to buses on busways was found.

  It is clear that the level of transfer depends, other things being equal, on the existing level of public transport use. A world city like Paris which has a relatively high modal split in favour of public transport can gain fewer additional car users than a city with a very low initial public transport share. The effect of rigorous hard complementary measures (such as road pricing or private and public parking charges) is decisive, whether the mode is light rail, guided bus, or buses operating on busways, though the actual figures for transfer will—in all cases—depend on the actual service, speed and fares offered. Bus lanes normally have the disadvantage that they do not give a clear right of way if car traffic is congested but the Dublin example shows that strict enforcement of bus lanes can have an astonishingly impressive effect. There has been significant discussion, on the Continent and in the US, about the "rail factor", suggesting that under equal conditions people will prefer rail to bus. This was also shown in our own survey in four British cities where we asked about 1,850 car drivers. About half (47 per cent) of the car drivers preferred light rail and 36 per cent guided bus, the rest not knowing. The problem for analysis is that conditions are usually not equal: the rail factor has not been researched adequately, thus a final conclusion is not possible.

Each mode can be used for different purposes

  Guided busways can be effective in overcoming bottlenecks when the road network is congested but this could be achieved more cheaply with strictly enforced bus lanes. In all cases guided busways and busways seem not to be suitable for city centres as they are too obtrusive and the feasibility for integration into a denser built up urban environment is difficult or impossible. In the best case these busways will become bus lanes. If that is the case then the question may arise why not use bus lanes for all those roads where priority is suggested.

  A guided bus network can be an innovative public transport system, to testing whether it works well in a medium sized free standing city like Northampton may have international significance. However, some politicians are reluctant to go for a system which has not already been tested elsewhere, and it may be that trials now planned in French cities will give British local authorities more confidence.

Overall policy evaluation

  The general policy evaluation which emerges from this research is that the decisive influence on the success of a policy of expanding public transport is not the specific mode favoured, but the political commitment to an overall strategy of reducing the dominance of car use in urban areas. Any of the main public transport modes, whether it is bus, guided bus or light rail, can secure expanding demand—if a high density, high quality service is provided, and if complementary measures (parking charges, large scale pedestrianisation, land-use policies etc) are vigorously implemented.

  In some cases, successful expansion of public transport has been preceded by detailed cost benefit studies, though this is not always the case. Sometimes this technical tool is hardly used at all, and even where it is used there is often a feeling of caution because of concerns that the figures are unreliable or prone to manipulation, or because the underlying decisions are much more influenced by other processes. In any case the results of such studies are typically subordinated to political considerations.

  From this point of view, we can reconsider the relative advantages of the different public transport modes.

  Light Rail. Its main advantages turn out to be what are often considered to be disadvantages—its high cost and inflexibility. In political terms, these attributes give it a high profile as a symbol of commitment in the early stages, and a confident, futuristic symbol of the city when it is implemented. "Inflexibility" becomes redefined as "security"—the population is confident that a change of political power or financial situation will not result in the new system being taken away from them, and can therefore plan their lives knowing that the system will be there in the future. Political and professional careers can and have been built around building a new light rail system. It has many friends—commercial, civic, political, environmental—and few enemies.

  Bus Priority. By the same argument, the main disadvantages of relying on conventional buses are what are usually assumed to be advantages—its cheapness and flexibility. This always gives the temptation to be too cautious in implementation, so that the service improvements—while overwhelmingly positive in terms of value for money—are simply too small to make a great impact. In effect, it requires much bolder political will to make a success of (cheap) bus priority networks than (expensive) light rail systems but if that will is there, then the balance of advantage is profound.

  Busways and existing guided buses emerge as useful additions to the instruments available for public transport, but probably limited to a specific fringe role—making use, on occasion, of disused rail lines (but not justifying replacing a still-functioning rail system), and for use in some outer areas. The main disadvantage of busways is their required width which is hardly available in European urban areas. They are unlikely to be implemented in town centres in any country. They both have some of the symbolic and career-enhancing qualities of light rail systems, though on a smaller scale. We do not consider that busways will be the central element of the public transport strategy of any European town—though they could be useful additions if the main strategy is right. The main disadvantage of the existing technology of guided busways, in current UK conditions, is that they may stimulate unrealistic ideas about massive systems which will never happen, thereby diverting attention from the core strategic questions. New types of guided buses, such as the TVR or Translohr may have some future, especially in middle-sized towns where they would operate like trams and not like buses and therefore would have some of the characteristics of light rail. However, significantly more practical experience and research are needed before a final judgement on the new generation of guided buses could be made.

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