Legibility gives drivers or pedestrians with normal vision the ability to understand symbols and letters on your sign. Legibility depends on many things, including the size of the letters and the amount of white space, among others.

While it’s tempting to include as much information as possible when designing your sign, it’s more effective to keep the message very simple. Prioritize what you need to communicate. If you offer a unique service in the area, your address may be the most important element. If you’re competing against many other similar businesses, highlighting distinctive features may be a priority.

Clutter, or “sign blight” is sure to confuse the customer. Maintain a clear and straightforward message.

This table determines the distance at which a sign first becomes legible, based on how fast a car is moving.

Speed of Traffic Minimum Required Legibility Distance
55 mph (88kph) 440′ (134 m)
50 mph (90 kph) 400′ (122 m)
45 mph (72 kph) 360′ (110 m)
40 mph (64 kph) 320′ (98 m)
35 mph (56 kph) 280′ (85 m)
30 mph (48 kph) 240′ (73 m)
25 mph (40 kph) 200′ (61 m)

Source: Schwab, Richard N.; also, Garvey, P.M., et al., 1996.