Speed Control and Transport Policy
From the introduction:
This study is addressed to two questions. What should the speed limit be on each class of road? By what means should speed limits be enforced? All the harmful impacts of traffic are connected with speed, and in most situations lower speeds would reduce these impacts, often very substantially. But lower speeds would significantly increase the time required for many of the journeys made at present. People would either have to accept this time penalty or modify their travel behaviour in order to reduce or avoid it. To determine the right speed limits involves predicting, with as much precision as possible, what would be the effects of enforcing different speed limits, including those which apply at present but are not observed, and then finding a way to strike a balance between the desirable and undesirable consequences.
Plowden, S. Hillman, M. (1996) Speed Control and Transport Policy, Policy Studies Institute, London.Read the PDF: Speed Control and Transport Policy