Introduction

Highway and transportation planning can be described as a process of making decisions which concerns the future of a given transport system. The decisions relate to the determination of future demand; the relationships and interactions which exist between the different modes of transport; the effect of the proposed system on both existing land uses and those proposed for the future; the economic, environmental, social and political impacts of the proposed system and the institutional structures in place to implement the proposal put forward.

 Transport planning is generally regarded as a rational process, i.e. a rational and orderly system for choosing between competing proposals at the planning stage of a project. It involves a combined process of information gathering and decision-making.

The five steps in the rational planning process are summarised in Table 1.3.

In the main, transport professionals and administrators subscribe to the values underlying rational planning and utilise this process in the form detailed below. The rational process is, however, a subset of the wider political decision-making system, and interacts directly with it both at the goal-setting stage and at the point in the process at which the preferred option is selected. In both situations, inputs from politicians and political/community groupings representing those with a direct interest in the transport proposal under scrutiny are essential in order to maximise the level of acceptance of the proposal under scrutiny.

Assuming that the rational model forms a central part of transport planning and that all options and criteria have been identified, the most important stage within this process is the evaluation/appraisal process used to select the most appropriate transport option. Broadly speaking, there are two categories of appraisal process. The first consists of a group of methods that require the assessments to be solely in money terms. They assess purely the economic consequences of the proposal under scrutiny. The second category consists of a set of more widely-based techniques that allow consideration of a wide range of decision criteria – environmental, social and political as well as economic, with assessments allowable in many forms, both monetary and non-monetary. The former group of methods are termed economic evaluations, with the latter termed multi-criteria evaluations.

Evaluation of transport proposals requires various procedures to be followed. These are ultimately intended to clarify the decision relating to their approval. It is a vital part of the planning process, be it the choice between different location options for a proposed highway or the prioritising of different transport alternatives listed within a state, regional or federal strategy. As part of the process by which a government approves a highway scheme, in addition to the carrying out of traffic studies to evaluate the future traffic flows that the proposed highway will have to cater for, two further assessments are of particular importance to the overall approval process for a given project proposal:

·         A monetary-based economic evaluation, generally termed a cost-benefit analysis (CBA)

·         A multi-criteria-based environmental evaluation, generally termed an environmental impact assessment (EIA)

Layered on top of the evaluation process is the need for public participation within the decision process. Although a potentially time consuming procedure, it has the advantages of giving the planners an understanding of the public’s concerns regarding the proposal and also actively draws all relevant interest groups into the decision-making system. The process, if properly conducted, should serve to give the decision-makers some reassurance that all those affected by the development have been properly consulted before the construction phase proceeds.

Economic assessment

Within the US, both economic and environmental evaluations form a central part of the regional transportation planning process called for by federal law when state level transportation plans required under the Intermodal Transportation Efficiency Act 1991 are being determined or in decisions by US federal organisations regarding the funding of discretionary programmes.

Cost-benefit analysis is the most widely used method of project appraisal throughout the world. Its origins can be traced back to a classic paper on the utility of public works by Dupuit (1844), written originally in the French language. The technique was first introduced in the US in the early part of the twentieth century with the advent of the Rivers and Harbours Act 1902 which required that any evaluation of a given development option must take explicit account of navigation benefits arising from the proposal, and these should be set against project costs, with the project only receiving financial support from the federal government in situations where benefits exceeded costs. Following this, a general primer, known as the ‘Green Book’, was prepared by the US Federal Interagency River Basin Committee (1950), detailing the general principles of economic analysis as they were to be applied to the formulation and evaluation of federally funded water resource projects. This formed the basis for the application of cost-benefit analysis to water resource proposals, where options were assessed on the basis of one criterion – their economic efficiency. In 1965 Dorfman released an extensive report applying cost-benefit analysis to developments outside the water resources sector. From the 1960s onwards the technique spread beyond the US and was utilised extensively to aid option choice in areas such as transportation.

Cost-benefit analysis is also widely used throughout Europe. The 1960s and 1970s witnessed a rapid expansion in the use of cost-benefit analysis within the UK as a tool for assessing major transportation projects. These studies included the cost-benefit analysis for the London Birmingham Motorway by Coburn Beesley and Reynolds (1960) and the economic analysis for the siting of the proposed third London airport by Flowerdew (1972). This growth was partly the result of the increased government involvement in the economy during the post-war period, and partly the result of the increased size and complexity of investment decisions in a modern industrial state. The computer programme COBA has been used since the early 1980s for the economic assessment of major highway schemes (DoT, 1982). It assesses the net value of a preferred scheme and can be used for determining the priority to be assigned to a specific scheme, for generating a shortlist of alignment options to be presented to local action groups for consultation purposes, or for the basic economic justification of a given corridor. In Ireland, the Department of Finance requires that all highway proposals are shown to have the capability of yielding a minimum economic return on investment before approval for the scheme will be granted.