The principles of integration in urban transport strategies

Integration as a principle in urban transport policy is frequently advocated but rarely defined. We suggest a range of types of integration, and highlight the problems in developing an effective integrated strategy, given the number of variables involved. We argue that integration should be designed to serve agreed objectives of transport policy, rather than being an objective in its own right.We then consider the principles for designing an effective integrated strategy. We define the concept of synergy, which is often advocated as a benefit of integration, and discuss whether it, and other aggregation benefits short of true synergy, is achievable. We then consider the alternative approach of using integration to overcome barriers, an approach, which is likely to be in conflict with pursuit of synergy, but more likely to lead to readily implemented strategies.We then review a number of examples where these principles have been applied, and investigate them to assess whether synergy has been demonstrated. Generally we find little evidence of synergy in outcome indicators. We conclude with some more general guidance on approaches to integration.