An empirical study of subjective road categorization

Abstract

Driver behaviour will partially be a function of the cognitive schemata by which drivers represent features, functions and operations of traffic system components. This paper uses the Repertory Grid Technique to address the questions: (1) How do drivers internally represent different categories of road? (2) How are those representations mapped on to ‘official’ road categories? A factor analysis of data obtained from 40 subjects revealed, in answer to question (1), that four factors, namely, ‘safety’; ‘urban/rural’; ‘road boundaries/slip-roads’; and ‘markings’; accounted for 82·3% of the variance. Multidimensional scaling and clustering analyses showed that subjective categorizations of roads are closely related to their objective physical characteristics, but less-well determined by ‘official’ road categories. Certain features (e.g. slip-roads, markings, obstacle-free boundaries) appear to contribute little to the subjective safety of roads. This suggests that the potential benefits of these safety features may be fully achieved since risk compensation mechanisms will not operate.