Cone of Vision

Cone of Vision

While driving, a motorist has a 20° range, or “cone of vision.” If your business has a sign whose setback (i.e., its distance) from the road is outside of this cone, then your sign is in danger of being overlooked.

The angle at which someone sees your sign influences how much time a driver has in order to react to that sign. A sign at 90° angle to the road would be the best option, while those parallel to the road are the hardest for drivers to see. In this table, Type I refers to signs that are at a 90° angle to the road, while Type II signs are those that are parallel to the road. See the difference in square footage?

Speed Limit
(miles/hour)
Lanes of Traffic Type I
Sign Size
(sq. ft.)
Type I
Height
(ft.)
Type II
Sign Size
(sq. ft.)
Type II
Height
(ft.)
25 2 25 12 50 12
25 4 32 12 70 12
35 2 36 20 75 20
35 4 42 20 90 20
45 2 75 35 100 40
45 4 90 35 120 40
55 2 150 50 250 90
Urban Freeway 300 74 450 90

Source: Schwab, Richard N.