What Makes it Legible?

The legibility of text may be influenced by several physical factors, including font size, contrast between the type and background, font color, and screen resolution. From the point of view of typographic designers, these are considered “extrinsic factors,” because they do not involve alteration of the graphical shapes of characters.

Legibility may also be influenced by several design factors considered “intrinsic factors,” because they involve the shapes of characters, also known as glyphs. These include a character’s height, width, weight, and whether or not it has serifs.

Which typeface attributes may have the potential of reducing driver distraction? Below are some examples (Reimer, Mehler, Dobres, Matteson, Gould, Chahine & Levantovsky, 2014):

  • Ample inter-character spacing
  • Open shapes
  • Varying proportions
  • Ample intra-character spacing
  • Unambiguous forms

Reimer, B., Mehler, B., Dobres, J., Coughlin, J.F., Matteson, S., Gould, D., Chahine, N. & Levantovsky, V. (2014). Assessing the Impact of Typeface Design in a Text Rich Automotive User Interface. Ergonomics .