1. Accidents at black spots: estimating the effectiveness of remedial treatment, with special reference to the ’regression-to-mean’ effect;Abbess;Traffic Eng. Control,1981
2. Evaluation of photo radar program in British Columbia;Chen;Accident Anal. Prev.,2000
3. Are mobile speed cameras effective? A controlled before and after study;Christie;Injury Prev.,2003
4. Statistical Power Analysis for the Behavioral Sciences;Cohen,1988
5. Road Safety Good Practice Guide. Department of the Environment, Transport and the Regions,2001