Road Sign Comprehension In The General Population: What Is Currently Known? Benjamin Taylor Measures of Road Sign Comprehension Forms of Road Sign Processing - Paper and Pencil Tests (e.g, Shinar et al., 2003) - Comprehension (e.g, Al-Madani, 2000) - Eye Movements (e.g, Crundall & Underwood, 2002) - Semantic Priming (e.g, Crundall, 2002) - Hazard Detection (Koyuncu & Amado, 2008) - Situation Awareness (e.g, Liu, 2014) - Depth Processing…not much (e.g, Liu, 2014) Rates of Comprehension - 50 – 62% (Al-Madani & Al-Janahi, 2002) - 38.5 – 42% (Charlton, 2006) - Depends of measure and context

Who understands road signs better than others? - Mixed evidence regarding age and driving experience - Older drivers show greater semantic priming for road signs, suggesting a greater degree of effective, unconscious processing of the signs’ messages (Charlton, 2006) - Some studies show greater explicit knowledge or road signs among younger drivers, with others revealing the same among older drivers (Creaser, 2007; Crundall & Underwood, 2002) - Driver use of road signs may differ with age: for novices, they are more important in maintaining safety and predictability - Semantic dementia and Alzheimer’s Disease associated with poorer comprehension (Luzzi et al., 2015) What sign features are associated with comprehensibility? - Conspicuity, semantic relatedness, glance legibility, familiarity, standardization (Ben-Bassat & Shinar, 2006; Shinar et al., 2003) - Signs that are simple and make sense

Reading Ability and Road Sign Comprehension - How do drivers with reading difficulties extract and comprehend visual and phonological information from signs in the fast pace driving environment? - Poorer recognition of road signs among people with dyslexia (Brachacki et al., 1996) - Poorer situation awareness of road signs for drivers with dyslexic symptoms (Taylor et al., 2016) - What are the relative roles of magnocellular and phonological deficits in abberant road sign processing? Commonly Misunderstood Signs - Railway Crossing with Lights Ahead (AUS); Taylor et al., 2016 - No Entry for Vehicles Carrying Explosives (POL); Shinar et al., 2003 - Truck Lane (AUS); Shinar et al., 2003 - Ambiguity, lack of semantic relatedness, concreteness... Add text or change picture? Combinatory features may be better in the first two, while verbal information may be more appropriate in the latter Point to consider in design: how abstract is the sign meaning?

Contact Details Insert image of presenting author here. (Optional) Ben Taylor B.Psych (Hons) Department of Psychology, Macquarie University, N.S.W, Australia Email: taylorb851@gmail.com Take home message: Some signs need to be designed better. Changes in patterns of road sign processing with age and experience need more investigation. Do additional factors emerge that impair/enhance road sign comprehension/adherence as drivers gain experience? Research needed on reading processes and road sign comprehension