With decreasing amounts of time to perceive objects changing, specific details are less noticeable, making spatial perception more difficult. It is evident then that design criteria for pedestrian oriented and motorist oriented signing should differ. The safety of the motorist and his passengers can depend upon the clarity of messages conveyed by signs. The focusing point as diagrammed here does not include the effect of preceding traffic. Legible typography is conducive to prolonging attention.
Type faces with fairly heavy and uniform strokes are most legible.
In addition to aiding legibility, liberal negative space, when enclosing the copy creates a target on which the viewers eye can focus quickly. This is especially important for glance legibility. Signs, just as highways, should be designed and constructed for the individual with poor vision, rather than for the average person. Signs should be designed, constructed and placed for easy readability. Pedestrian oriented and motorist oriented signs have difference criteria of design.