In November 1992, the UK Department of Transport (DOT) commissioned The MVA Consultancy to investigate the effectiveness of parking as a demand management mechanism, as part of its wider research programme into congestion and its cures. This research aims to study how to use parking controls to reduce traffic demand in congested urban areas, either alone or combined with complementary measures. The research is being conducted in several stages, and presented in a series of papers. This first paper explains the results of Stage One and reports the first case study of Stage Two. The key issues identified in Stage One were the effects of parking controls on travel patterns, demand, congestion, and the mechanisms for controlling parking. Parking demand can be managed by better enforcement, changing the cost of parking, and changing the amount of parking space available. The effects of parking controls need to be modelled by land use and transport interaction models, travel demand models, and congested assignment models. Parking strategies are to be assessed by comparing situations with strategies in place with a base situation; the assessment framework is outlined. The first case study, in Bristol, is described; it includes a travel survey, interviews with drivers, stated preference surveys, and tests.