The Orbit Multi-Modal Study: Developing a Long Term Sustainable Management Strategy for the M25
R Thompson, D Hardcastle, E Strankalis, Kellog Brown and Root; D Coombe, The Denvil Coombe Practice, UK
The London Orbital Multi-Modal Study (Orbit) was one of a series of multi-modal studies undertaken for the Department for Transport (DfT). Multi-modal studies have examined problems of congestion on the strategic road network and sought solutions from all modes of transport. The overall aim of Orbit was to examine the existing and future problems for orbital travel around London and to produce a long-term sustainable management strategy for the M25, which met the Government?s objectives for transport and solved, or at least ameliorated, the problems on the M25, both now and in the future.
The congested sections of the M25 carry high volumes of car drivers with widely dispersed origins and destinations, many travel long distances, and most travel alone in their car. Most could not make their journeys efficiently using the existing public transport system. The reasons why this pattern of travel has arisen are many and varied. Over the last two decades, people have tended to move out of London to live in places where housing is more affordable and the environment more amenable, and new business parks, retail and leisure developments have tended to locate on out-of-town sites in and adjacent to the M25 corridor. A generally good trunk and motorway road system has been provided outside London, car prices have not increased in real terms over a long period and have decreased in very recent years, and the price of fuel in terms of pence per mile has decreased in real terms, especially recently in response to the Government?s policy of encouraging the use of more efficient engines. All these factors have contributed to the widely dispersed patterns of long-distance car commuting on the M25.
Government forecasts indicate that, between 1997 and 2016, there will be 10% more people, 19% more households, 15% more jobs and 34% more cars in the Orbit study area. As a result, without the Recommended Strategy, travel times would markedly increase and journeys would become even more unreliable.
A range of measures designed to contribute to a long-term, sustainable management strategy for the M25 was considered, including ways of making better use of the existing transport system, ways of reducing traffic, ways of improving public transport and providing other alternatives to the car. It was concluded that these measures could not be relied upon to yield substantial traffic reductions on motorways, to a significant extent because of the lack of control over extra traffic induced by the reduced congestion brought about the measures.
It was also concluded that it would be very difficult (if not impossible), and certainly environmentally damaging and costly, to build sufficient new road capacity to meet future demands and provide an acceptable and guaranteed level of service ? in short, we could not build our way out of congestion.
Thus, road building on its own was not considered to be the answer. If extra road capacity was provided on the M25 without any means of controlling the use made of the improved motorway, then within a few years, there would be further calls for yet more road capacity. This ever-continuing cycle of road building would be unsustainable ? it would simply encourage a greater dispersal and increased scale of long-distance car commuting which has caused the congestion experienced today. This approach would therefore fundamentally fail to represent a long-term sustainable strategy for the M25, as required by the study brief. As the Government says in its 10 Year Plan: ?Simply building more and bigger roads is not the answer: we need a more strategic approach.?.
The recommended solution was to combine road construction with the measures to reduce and control traffic levels. It was found that area-wide road user charging would substantially reduce both the volume of car commuting and the average length of commuting trips by car on the M25. The charged area would include London, the M25 and a large part of south east England, but a national scheme would be preferred. No other policy could be identified which would reduce car commuting by anything other than a very marginal extent without also having substantial adverse impacts on the economy. The study team was under no illusion about the scale of challenge presented by an area-wide road charging scheme. As a result, alternative approaches to control induced traffic were considered, including ramp metering and tolls on the widened sections of the motorway.
Although the 10 Year Plan does not specifically mention the need to de-couple traffic growth from economic growth, this appears to be the implication from the acceptance that continued road building is not the answer. Whilst there is little experience of de-coupling traffic growth from economic growth at the stage of development of the UK economy, one possible way is through the application of area-wide road user charging. Area-wide road user charging has the potential to de-couple traffic growth from economic growth, at least to some extent, by increasing the charges and thereby reducing the extra capacity required. In these circumstances, therefore, it is possible that traffic growth can be contained without inhibiting economic growth.
It was also concluded that developments in the vicinity of the M25 which generate large volumes of car trips need to be controlled so that the benefits of the newly provided road capacity are not eroded. It was recommended that a review of the current controls on land-use development adjacent to the trunk road and motorway network should be undertaken, aimed at further emphasising regeneration and urban renaissance policies and further minimising the location of developments generating large volumes of car traffic close to trunk road and motorway junctions.
Travel times and reliability would be better than in 1997 and these benefits would be maintained through to 2021 and beyond. As a result the Strategy offers the real prospect of a sustainable road transport system over the next 2 decades or more. The paper will outline the nature of the problems on the M25 and their causes. In passing, it will note that the problems are not unique to the M25 but are likely to apply to strategic roads throughout the UK and Europe. The paper will then discuss the alternative ways of tackling the problems and explain the rationale for the proposed
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