Viewing Information
Proper Display Size
Character height is one of the most important aspects of effective communication. Typical viewing distance is determined as 50 feet for every inch of character height. The benefit of an electronic display is the ability to display multiple changes of message copy. Character height should be selected to provide an optimum viewing time of 15-20 seconds at normal traffic speed. Unusual situations, where setbacks and obstacles are an issue, require additional character height for optimum viewing. The table below demonstrates optimum character height of at least 18” at 35 mph and 36” or more at 65 mph.
Character Height | Reading Distance | 20 mph | 25 mph | 35 mph | 40 mph | 50 mph | 55 mph | 60 mph |
| 9" | 450' | 15.4 | 11.6 | 8.8 | 7.7 | 6.4 | 5.2 | 4.7 |
| 12" | 525' | 17.9 | 13.6 | 10.2 | 8.9 | 7.2 | 6.1 | 5.5 |
| 18" | 900' | 30.7 | 24.5 | 17.5 | 15.3 | 12.3 | 11.2 | 9.4 |
| 24" | 1200' | 41.0 | 32.7 | 23.4 | 20.4 | 16.4 | 14.9 | 12.6 |
| 30" | 1500' | 51.2 | 40.9 | 29.1 | 25.6 | 20.5 | 18.6 | 15.7 |
| 36" | 1800' | 61.4 | 49.1 | 35.1 | 30.7 | 24.6 | 22.3 | 18.9 |
| 48" | 2400' | 81.9 | 65.4 | 46.8 | 40.9 | 32.7 | 29.7 | 25.2 |
| 60" | 3600' | 102.4 | 81.7 | 58.5 | 51.1 | 40.9 | 37.2 | 31.5 |
Matrix & Column Count
The display matrix is the number of pixels (LED clusters) defined by rows (height) and columns (length). The industry has defined standard characters as those created using 7-pixels high and 4-pixels in length. A display matrix of 24x80 can accommodate 3 lines of 16 characters per line of the 4 pixel long characters allowing for a vertical space between each 7x4 character. Usable column length will differ depending on type of user. Illustrated below is the capacity of various display matrices based on standard, non-bold, non-condensed 7x4 characters.
| Characters per Line | |||||||
| 9 | 11 | 12 | 14 | 16 | 17 | 19 | |
| 1 Line | 7 x48 | 7 x 56 | 7 x 64 | 7 x 72 | 7 x 80 | 7 x 88 | 7 x 96 |
| 2 Lines | 16 x 48 | 16 x 56 | 16 x 64 | 16 x 72 | 16 x 80 | 16 x 88 | 16 x 96 |
| 3 Lines | 24 x 48 | 24 x 56 | 24 x 64 | 24 x 72 | 24 x 80 | 24 x 88 | 24 x 96 |
| 4 Lines | 32 x 48 | 32 x 56 | 32 x 64 | 32 x 72 | 32 x 80 | 32 x 88 | 32 x 96 |
| 5 Lines | 40 x 48 | 40 x 56 | 40 x 64 | 40 x 72 | 40 x 80 | 40 x 88 | 40 x 96 |
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