Supplementary memorandum by London Transport
(RT 27A)
LIGHT RAPID TRANSIT
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 corridorfor 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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