Environmental impact assessment (EIA) is used to evaluate big projects and their effects on the environment. The study looks at how well EIA works in the UK since 1988, and if it's seen as a separate task or part of the project process. It examines issues like when to do an EIA, how it helps pick the best project options, and balancing different environmental factors. The study also considers how EIA can be used to assess planning and transport policies, and suggests ways to improve current practices.