Appraisal
The processes used to support transport related decision-making, fall into two main categories, namely: assessment and evaluation.
In effect, a two-stage approach is needed for the management and planning of integrated transport investment, the first being a more strategic assessment at an outline or concept level, and the second a more detailed and specific evaluation in response to specific circumstances.
Assessment
Assessment takes into account a broad range of objectives in order to develop strategies and plans within an appropriate and co-ordinated context. Assessment at the strategic level provides a context for detailed evaluation.
Assessment is of most value if it is quantified and integrated with wider objectives and strategic value can be established through such techniques as cost effectiveness assessment.
Scenario testing is needed in many cases to supplement simple forecasting methods. This may test how future transport system conditions may vary when assessments are undertaken. For example, if it is thought that pricing arrangements may change in the future, this can be allowed for in evaluation and assessment methodologies.
Evaluation
Evaluation represents a narrower pre or post-investment scrutiny of proposals. The detailed evaluation of proposals is important and usually includes operational factors, (travel time, vehicle costs and safety). Detailed evaluation can also take account of detailed environmental, social and economic aspects.
Cost benefit analysis
This sometimes termed 'economic evaluation' or 'economic appraisal' and is a technique used to compare monetised costs and benefits.
Cost benefit analysis is typically applied to the detailed evaluation of packages and proposals (see also separate page on cost benefit analysis)