Appraisal of a Motorway Widening Project, Including CO2 Emissions



Appraisal of a Motorway Widening Project, Including CO2 Emissions

Introduction

London, in common with all large cities, depends on a highly developed and widespread network of public transport and roads to allow it to function. The agglomeration benefits identified in major metropolitan economies are, to a significant degree, facilitated by the suburban railways, metros, tramways, motorways, and local roads that allow movement. Without the capacity to move millions of people into and around a densely settled metropolis, cities cannot exist. Despite the development of the post, the telegraph, the telephone, and the internet, people still derive economic benefit from congregating in large numbers in and around city centres.

Few issues have dominated the London policy debate in the past 25 years as much as transport. After decades of relative economic decline and population shrinkage in the years since 1945, the capital's population and economy expanded relative to the rest of the country in the period after 1985. This growth led to congestion on the public transport systems which, for many years, had been allowed to decline. In the years since the publication of the Central London Rail Study (CLRS) in 1989, efforts have been made to add substantial rail capacity in London. A few new lines—or parts of lines—have been developed in the last 15 years, notably the Jubilee Line extension, additions to the Docklands Light Railway (DLR), the Heathrow Express, and Croydon Tramlink. However, the condition of the core Underground and commuter railway systems has continued to decline, although complex re-investment policies have been implemented since the early 2000s.

The CLRS proposed schemes that have subsequently been considered in more detail, though with varying degrees of progress. These schemes included a Chelsea-Hackney underground line, a north-south 'Thameslink', an east-west Crossrail, and a north-south Crossrail. By far the most developed of these has been the east-west Crossrail, though it is important to note that none of the schemes—including the relatively low-cost Thameslink scheme—has yet been built and opened. The CLRS also listed an extension to the Jubilee Line which, in a different form, was completed at the end of 1999.

Discussion

The UK's Office for National Statistics measures the economic output of areas within the country on the basis of a 'gross value added' (GVA) calculation. In the case of London and its surrounding areas, there is a significant amount of commuting into the city, which means that the 'residence-based' figures shown in Table 6 are lower than 'workplace-based' numbers by between one and two percentage points. Thus, for example, the workplace-based GVA figure for London in 2006 was 18.8 per cent, compared with the 17 per cent shown for the residence-based total.

M25 widening project

The widening works from junctions 16 to 23 began in July 2009 and the section between junctions 16 and 18 was completed in 2010. The sections from junctions 18 to 23 are expected to be completed before 2012 Olympic Games. Works on Junction 21a were completed in September ...