Brief Communication: Impact of Sign Character Aspect Ratio on Legibility

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John D. Bullough


Signs are critical elements of the visual environment for pedestrians, drivers and other users. Regardless of their purpose, signs should be easily detected and readily legible. Tools such as visual performance models have been developed to allow the assessment of the speed and accuracy with which observers can read information on a sign. These models include factors such as the luminance of the sign, the contrast between the sign's characters and their backgrounds, and the size of the characters. One factor that has not been included in visual performance models is the aspect ratio of characters, particularly of alphanumeric symbols. To address this, a small study was carried out to investigate observers' ability to identify characters ranging in contrast and aspect ratio.

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Bullough JD. 2016. Discussion of "Legibility of the Clearview typeface and FHWA standard alphabets on negative- and positive-contrast signs" by Garvey et al. Transportation Research Record 2555: 36-37.

Carter R, Day B, Meggs P. 1985. Typographic Design: Form and Communication. New York, NY: Van Nostrand Reinhold.

Center for Inclusive Design and Environmental Access. 2010. Design Resources: Text Legibility and Readability of Large Format Signs in Buildings and Sites, DR-11. Buffalo, NY: University at Buffalo.

Garvey PM, Pietrucha MT, Meeker D. 1997. Effects of font and capitalization on legibility of guide signs. Transportation Research Record 1605: 73-79.

Garvey PM, Zineddin AZ, Pietrucha MT. 2001. Letter legibility for signs and other large format applications. Proceedings of the Human Factors and Ergonomics Society 45th Annual Meeting, pp. 1443-1447.

Garvey PM, Chirwa KN, Meeker DT, Pietrucha MT, Zineddin AZ, Ghebrial RS, Montalbano J. 2004. New font and arrow for National Park Service guide signs. Transportation Research Record 1862: 1-9.

Garvey PM, Klena MJ, Eie W-Y, Meeker DT, Pietrucha MT. 2016. Legibility of the Clearview typeface and FHWA standard alphabets on negative- and positive-contrast signs. Transportation Research Record 2555: 28-36.

Kuhn BT, Garvey PM, Pietrucha MT. 1998. Sign Legibility: The Impact of Color and Illumination on Typical On-Premise Sign Font Legibility. Bristol, PA: United States Sign Council Foundation.

Rea MS, Ouellette MJ. 1991. Relative visual performance: A basis for application. Lighting Research and Technology 23(3): 135-144.

Tinker MA. 1963. Legibility of Print. Ames, IA: University of Iowa Press.