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

Supplementary memorandum by London Transport (RT 27A)


  I am replying to the letter dated 28 January seeking a supplementary note on three topics and I apologise for the delay in responding.

1.  The preferred development densities to support light rail and other LRT schemes

  In broad terms conventional buses are appropriate for demand levels up to around 2,000 passengers per hour, bus based transit schemes for demand levels between 2,000 and 5,000 per hour, light rail for demand level of between 2,000 and around 10,000 per hour and metros for over 10,000 passengers per hour.

  Demand levels on any particular corridor are determined by a number of factors. Population density is one factor and it is generally accepted that densities of at least 120 persons per acre are needed for public transport to be viable. However, equally important is the density of destination attractions along the corridor—for example the scale of work, education and leisure activities. A corridor will need to have a good mix of land use development, preferably clustered around the transit stops if it is to attract sufficient people to justify running a conventional bus based public transport service.

  Higher levels of investment above a conventional bus can generally only be justified where the route serves a dense level of attractions such as in a city centre and/or where additional demand is attracted along the main part of the route from a wider catchment than the typical 10-15 minute maximum walking catchment of a route. This can be achieved by providing interchanges with other services such as a rail or feeder bus and taxi services and measures to attract feeder car trips such as Park & Ride and Kiss & Ride facilities.

  In developing the transport strategy to support the Thames Gateway development, the approach has been to identify key local corridors on which some form of Intermediate Mode services could run, linking new residential areas with existing job opportunities and town centres and providing feeder links to the established (mainly radial) Underground and National Rail networks. Our work so far suggests that, in general, the scale and density of the proposed new developments in the Thames Gateway will not generally justify investment in light rail systems and that bus based schemes are more likely to be viable. On the other hand two of our current Intermediate Mode proposals; for the Uxbridge Road corridor and for central London, between Euston and Waterloo, suggest that light rail might be worth considering further.

2.  To what extent will it be possible to narrow the "quality gap" between the bus and light rail in order to improve how the former is perceived

  When making a comparison between bus and light rail systems it is important to compare like with like. Light rail services, particularly new ones, are most often developed as systems with a number of features in addition to the actual vehicle. Whilst the quality of buses has improved significantly over recent years, few bus services are developed as part of a new system in the same way. To improve the quality of a bus based service, some or all of the elements typically used in light rail systems need to be introduced. These will include:

    —  routes protected as far as possible from obstruction by traffic congestion;

    —  high quality stops with shelters, real-time information and security;

    —  an accessible system with level and gap free boarding;

    —  a smooth ride provided by a well engineered road;

    —  modern ticketing and information facilities.

  LT has undertaken a study of bus based alternatives to light rail in conjunction with the PTE's and the Netherlands Ministry of Transport—"Rapid Transit on Rubber Tyres", the main conclusions of which are:

    —  there are few examples of bus based transit systems on which to make a fair comparison;

    —  they tend to have lower capacity than light rail and are used where light rail is not justified;

    —  there is a paucity of research on the ability of bus based systems to attract people from cars;

    —  the cost savings compared with light rail may not be that significant.

  London Transport Millennium Transit system serving the Dome in Greenwich is seen as a demonstration project incorporating a number of features to enhance the quality of service including high quality buses with air conditioning, a (part) segregated busway route, raised platforms allowing easier boarding, an electronic guidance of the vehicles on the busway and high quality stops and shelters. When this service is fully operational we will be undertaking surveys to understand how people perceive these facilities and use the service.

  RATP in Paris is undertaking a number of experiments with different bus based transit systems running on its Val de Marne busway. Three different vehicles are being tested including mechanical and electrical guidance and electric traction. LT is intending to co-operate with RATP in a forthcoming European Union sponsored research programme to undertake research into passenger perception and use of the different systems. In conjunction with DETR, LT is also undertaking research into the perception and use of the Croydon Tramlink to understand the differences in perception between trams and conventional buses.

  It is anticipated that this research will improve our understanding of the relative importance people place on elements of the different systems and lead to the improvement of bus based alternatives.

3.  Can an incremental approach be adopted

  There are a number of advantages of adopting an incremental approach to the development of transit schemes but it is not appropriate for all circumstances.

  The main advantages are the spreading of capital costs over a longer period and, in places where demand levels are uncertain or only anticipated to grow over a long period, to allow the capacity of the system to grow in line with demand levels. The disadvantage is that the overall cost can be higher and there is inevitably a degree of disruption during the upgrading process.

  Such an approach is in principal being adopted by London Transport in the development of the current Intermediate Mode proposals. Schemes are being developed for the Uxbridge Road and the Euston-Waterloo corridor but in the meantime these routes are also being developed with higher priority and improved facilities for conventional buses. If the decision is taken to proceed with Intermediate Mode schemes on these routes one of the approaches may be to gradually give conventional buses more and more priority until the performance, demand levels and economics justify the introduction of light rail. A similar approach is being adopted in east London where an Intermediate Mode route is being developed with the initial intention that it would be used by an extension of the Millennium Transit service, but with the longer term capability of being converted into a tram based scheme if economically justified.

  In other circumstances an incremental approach is not possible or recommended. Although a busway alternative to the Docklands Light Railway was considered for east London the route and structures for the former would not have been appropriate for later upgrading. The busway would have required wider structures and it would not have been possible to share existing National Railway structures as has been achieved in several locations. Similarly with Croydon Tramlink there are a number of former railway rights of way along which it would not have been possible to run buses and in places the system shares an alignment with the National Rail services.

  An additional consideration is the need for much closer integration of transport and land use development. If this is to be successfully achieved the developer needs certainty about the scale and timing of the transport provision. An incremental approach could introduce a significant degree of uncertainty.

  I trust these responses assist the Committee's deliberations.

Jon Willis, Head of Project Development

Transport Strategy

28 February 2000

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