Abstract
Promoting bike use is an important transport policy objective in the Netherlands. In particular, car trips are expected to be substituted by bike. The paper shows to what extent trips made by car are actually perceived to be substitutable by bike. It focuses on favourable situations as well: conditions under which substitution is at its highest. Considerable differences as to the degree of substitution appear to exist. The paper describes the conceivable effects of a bike promoting policy given the substitutability established. Such a policy is broadly supported.