The purpose of this paper is fourfold: to point out that the assessment of the benefits of an ATC scheme cannot be made properly without consideration of the re-distributional effects; to emphasise the importance of the interaction between ATC signal plans and traffic flow patterns; to show that the continual optimisation of signal plans can lead to a gradual deterioration of the network performance; and to demonstrate that traffic management measures (such as the banning of turning movements and the introduction of one-way schemes), and route control ideas, can be applied in conjunction with ATC policies to improve the performance of a network. (A) /TRRL/