How accurately does the public perceive differences in transport risks? An exploratory analysis of scales representing perceived risk.

This paper probes the extent to which the public accurately perceives differences in transport risks. The paper is based on a survey of a random sample of the Norwegian population, conducted in September 2003. In the survey, respondents were asked: "How safe do you think it is to travel by means of (bus, train, etc.)?" Answers were given as: very safe, safe, a little unsafe, and very unsafe. A cursory examination of the answers suggested that the Norwegian public was quite well informed about differences in the risk of accident between different modes of transport, as well as between groups formed according to age and gender for each mode of transport. This paper probes the relationship between statistical estimates of risk and summary representations of perceived risk more systematically. It is found that the differences in fatality rate between different modes of transport are quite well perceived by the Norwegian public, irrespective of the way in which perceived risk is represented numerically. The relationship between statistical estimates of risk and numerical representations of perceived risk for each mode of transport is more sensitive to the choice of a numerical representation of perceived risk. A scale in which the answer "very safe" is assigned the value of 0.01 and the answer "very unsafe" is assigned the value of 10 is found to perform quite well. When the perception of risk is represented numerically according to this scale, a positive correlation between statistically estimated risk and perceived risk is found in seven of the eight comparisons that were made to determine how well variation in accident rates according to age and gender for car occupants, car drivers, cyclists and pedestrians are perceived.