TRAFFIC CONFLICT STUDIES IN THE UNITED KINGDOM

Studies in the United Kingdom are mainly concerned with the development of the traffic conflict technique as a viable research and operational tool: (1) to obtain objective records of road user behaviour in "accident" situations for further analysis; (2) to provide a measure of safety to be used in "before and after" studies to evaluate accident countermeasures; (3) to evaluate the present state of a given location with respect to safety. Five grades of conflict severity are defined. The two methods of measurement: (1) observation of evasive action and (2) automatic detection of vehicle proximities from computer analysis of continuously recorded data from vehicle sensors, are discussed, particularly from the point of view of validity, reliability of observers, day to day variability and conflict types and differences in accident/conflict ratios. Some examples of before and after studies in the United Kingdom are given and possible future research is discussed. (TRRL)