letter visibility chart
| Letter Size | Letters Per Linear Foot | Readable Distance |
| 4" | 4 | 150 Feet |
| 6" | 2 ¾ | 200 Feet |
| 8" | 2 | 350 Feet |
| 10" | 1¾ | 450 Feet |
| 12" | 1½ | 525 Feet |
Information provided by the Pennsylvania Transportation Institute, Penn State University, United States Sign Council to show viewing distance and minimum letter height.