The effects of police patrolling on trunk road traffic

Police patrols are normally allocated to traffic duties with the objective of influencing driver behaviour, and thereby reducing road accidents. When scheduling police traffic patrol resources between routes it is therefore important to know what effect they might be expected to produce, on both driver behaviour and accidents. Similarly, knowledge of these effects are important in deciding the extent of the nation's resources to be allocated to this purpose. This thesis explores the effects of changes in the levels and tactics of police patrolling on driver behaviour, and on the accident rate. Previous published work is analysed and discussed, together with new experiments conducted in the Durham Constabulary Area. In carrying out these experiments, weaknesses in police and traffic engineering procedures became apparent. These too are discussed in detail. No statistically significant changes were observed, in the accident rate, or in any of the measures of driver behaviour investigated, in the presence of various levels and tactics of police patrolling. This was despite quite narrow confidence limits on most of the measures of driver behaviour.