62 Highway Engineering
on the environment. Environmental evaluation therefore requires an alternative
analytical structure. The structure developed within the last 30 years is termed
environmental impact assessment (EIA).
The procedure has its origins in the US during the 1960s when environmen-
tal issues gained in importance. The legal necessity for public consultation
during the planning stage of a highways project, allied to the preoccupation
with environmental issues by environmental groups, resulted in the identified
need for environmental assessment within the project planning process.
The process was made statutory under the National Environmental Policy Act
1969 which requires the preparation of an environmental impact statement
(EIS) for any environmentally significant project undertaken by the federal
government. NEPA prescribes a format for the EIS, requiring the developer
to assess: The probable environmental impact of the proposal
Any unavoidable environmental impacts
Alternative options to the proposal
Short-run and long-run effects of the proposal and any relationship between
the two
Any irreversible commitment of resources necessitated by the proposal.This list aids the identification and evaluation of all impacts relevant to the
evaluation of the project concerned.
Interest in EIA spread to Europe during the 1970s in response to the per-
ceived shortcomings within the then existing procedures for assessing the envi-
ronmental consequences of large-scale development projects and for predicting
the long-term direct and indirect environmental and social effects. The advan-
tages of such a procedure was noted by the European Commission, and the con-
tribution of EIA to proper environmental management was noted in the Second
Action Programme on the Environment, published by them in 1977. A central
objective of this programme was to put in place a mechanism for ensuring that
the effects on the environment of development projects such as major highway
schemes would be taken into account at the earliest possible stages within their
planning process. A directive (85/337/EEC) (Council of the European Commu-
nities, 1985) giving full effect to these elements of European Union policy was
agreed and passed in July 1985 with the requirement that it be transposed into
the legislation of every member state within three years.
The directive helps ensure that adequate consideration is given to the envi-
ronmental effects of a development project by providing a mechanism for ensur-
ing that the environmental factors relevant to the project under examination are
properly considered within a formal statement – the EIS – structured along
broadly the same lines as the US model.
The directive also details the minimum information that must be contained
within the EIS. These include: