Letter Visibility Charts

LETTER HEIGHT

READABLE DISTANCE FOR MAXIMUM impact

MAXIMUM READABLE DISTANCE

3"

30'

100'

4"

40'

150'

6"

60'

200'

8"

80'

350'

9"

90'

400'

10"

100'

450'

12"

120'

525'

15"

150'

630'

18"

180'

750'

24"

240'

1000'

30"

300'

1250'

36"

360'

1500'

42"

420'

1750'

48"

480'

2000'

54"

540'

2250'

60"

600'

2500'

NOTE:  The distances will vary approximately 10% with various color combinations.  Maximum distance is in color with RED or BLACK on a WHITE background.   5,280' equals one (1) mile.

Prepared by the California Institute of Technology

MAXIMUM impact READING TIME

(The length of time letters are readable

 when moving towards them)

30 MPH

40 MPH

60 MPH

80 MPH

  6" LETTERS

1.4 Seconds

1 Second

  0.7 Seconds

0.5 Seconds

  8" LETTERS

1.8 Seconds

1.4 Seconds

  0.9 Seconds

0.7 Seconds

12" LETTERS

   3 Seconds

   2 Seconds

 1.5 Seconds

 1 Second

18" LETTERS

   4 Seconds

   3 Seconds

    2 Seconds

1.5 Seconds

24" LETTERS

5.5 Seconds

   4 Seconds

2.75 Seconds

   2 Seconds

36" LETTERS

   8 Seconds

   6 Seconds

     4 Seconds

   3 Seconds

Prepared by Signs Manufacturing Corporation