How and why planners make plans which, if implemented, cause growth in traffic volumes : explanations related to the expert knowledge, the planners, and the plan-making processes

Traffic volumes need to be reduced in order to reduce GHG emissions and avoid dangerous global warming. This is also a means to reduce local health and environment problems, congestion and land take, save energy, make cities more liveable, and more. Despite long standing objectives, knowledge of how to achieve this, and public control of the most important means, land use and transport-systems are continuously planned and developed in ways which cause growth in traffic volumes. In order to be able to change this situation, we need to understand what is causing that traffic-increasing plans are made. The intention of this work has therefore been to contribute to answer the following research question: How and why are planners making plans which, if implemented, cause growth in traffic volumes? Within an understanding of planning processes as complex and involving numerous actors, I have chosen to focus on planners working for public and private actors, how they interact with each other when making zoning plans, and how they apply relevant expert knowledge. Planners are important actors in planning processes, since they possess procedural and substantial knowledge, and since they normally do most of the concrete plan-making. To my knowledge, this angle is not well covered by current planning literature and theory. Inspired by among others Jacobs, ‘how the city works’ as well as the plan-making processes have been conceptualised as systems of organised complexity. The research has been strongly influenced by the strand of philosophy of science termed Critical realism, as well as by Flyvbjerg’s ‘phronetic planning research’. Classical planning theory has been the most influential planning theory. The planners, my understanding of the state-of-the-art expert knowledge and the plan-making processes have been explored in abstract analyses, disclosing potential causal powers, mechanisms and conditions that can contribute to explaining how and why planners make traffic increasing plans. The findings have been examined in empirical studies; a survey and two interview studies among planners, as well as a case study of four plan-making processes. More general or transfactual explanations have been developed in the final analysis. It was found that when a public or private developer initiates a planning process in order to be allowed to implement a project, a number of mechanisms may be activated through which causal powers can act and produce traffic-increasing plans: The objective ‘reducing traffic volumes’ may not be introduced in or ousted from the plan-making process, the expert knowledge in question may not be introduced in or ousted from the process, or applied wrongly. Whether these mechanisms are activated, and whether traffic-increasing plans are made, depend on a number of contingent conditions. This regards among others that even if the expert knowledge is good enough to guide planners who aim at making traffic-reducing plans, it has shortcomings. This regards lack of accessible descriptions of the general knowledge and of the methods that are applicable in planning practise, as well as shortcomings of the empirical knowledge. This makes it less usable, and easier to oust. The planners know the expert knowledge in question, but few know it well enough to apply it in complex analyses or in tough debates. Regarding the plan-making processes, the objectives, knowledge and powers of the planners involved matter. It strongly affects which objectives are prioritised in the process and which knowledge is applied, and hence which plan that is made. Recommendations regarding what could be done to change the situation have been suggested