The Joint Roads Policing Unit of Thames Valley Police and Hampshire Constabulary commissioned TRL to evaluate the effectiveness of their roads policing strategy in terms of reducing the number of people killed and seriously injured in road collisions. The focus was on the fatal four causes of collisions: speeding, drink-driving, not wearing a seat belt and drivers using mobile phones.
TRL carried out a detailed literature review, in-depth review and analysis of police offence and collision data, and carried out a series of compliance surveys. This research estimated the non-compliance levels for each of the fatal four and estimated the numbers of lives that could be saved with increased compliance.
The research evidence resulted in a series of recommendations aimed at improving the efficiency and effectiveness of their current strategy. Non-compliance was highest for the use of child restraints (13%), followed by restraint use for all vehicle occupants, and lowest for drink-driving. However, the impact of these various illegal actions varies. Based on the estimated compliance levels, the potential casualty savings if compliance for each of these offences were increased to full compliance is highest for mobile phone use and drink-driving.
A summary of this report is available at

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