Comprehensibility of traffic signs in Turkey: the effects of cognitive sign design features and user factors

Abstract

The correct and easy comprehension of traffic signs is essential for the effective traffic control and safe driving. It is known that comprehension varies widely among different traffic signs symbols, road user characteristics and also countries. Therefore, the main objective of this study was to examine the comprehensibility of Turkish traffic signs, investigate the effect of cognitive sign design features and user characteristics on comprehension, and understand the interrelationship between them. 100 male and 101 female volunteers aged between 18 and 69 years with family roots from all seven regions of Turkey were the participates of the study. 60 Turkish traffics signs were guessed and cognitive sign design features; familiarity, concreteness, simplicity, meaningfulness and semantics closeness were rated by participants for the each sign. The effects of age, gender, marital status, educational background, active car driving experience and smoking habits were evaluated in the study. Through statistical analyses descriptive values of guessability score as an indicator of comprehension and factor effects were determined. Current traffic signs were not guessed well with the 39.2% guessability score by the population. More than 50% of the participants could not guess the meaning of the 35% traffic signs. 5 signs were comprehended as opposite of their true meaning. Guessability score is highly and positively affected by familiarity, meaningfulness and semantic closeness. Age was found a significant predictor of guessability score where moderately effected by active car driving and marital status. Comprehension decreased with age and increased with driving experience. Guessability performance was not related with the educational background but performance increased when educational level increased. Road works sign was found more familiar, concrete, simple, meaningful and semantically close, followed by warning type. This was the first study that evaluates the effect of both the sign design features and user characteristics on the sign comprehension. The results can serve as a reference in design of traffic signs not only in Turkey but also in the world.