- When a vehicle crosses a major road from a right-skewed minor road, the motorist has an unobstructed line of sight over their left shoulder. But some drivers may not be able to turn their bodies to take advantage of this unobstructed view. Table 10.5 lists available sight distances and design speeds for 14.4 ft and 17.7 ft setbacks. Use the older-driver vision angle if possible — it benefits older drivers and drivers whose physical limitations prevent them from fully turning their bodies.
| Table 10.5 Available Sight Distances and Design Speeds for 14.4 ft and 17.7 ft Setbacks | ||||||||
| Intersection Angle (Degrees) | Resulting ASD for a 17.7 ft Setback | Resulting ASD for a 14.4 ft Setback | ||||||
| Other-Driver Vision Angle: 115° | Older-Driver Vision Angle: 95° | Minimum Vision Angle: 13.5° | Older-Driver Vision Angle: 95° | |||||
| ASD (ft) | Design Speed (mph) | ASD (ft) | Design Speed (mph) | ASD (ft) | Design Speed (mph) | ASD (ft) | Design Speed (mph) | |
| 55 | 130 | 22 | 49.5 | 11 | 115 | 30 | 44 | 10 |
| 60 | 255 | 36 | 57.7 | 12 | 224 | 33 | 51 | 11 |
| 65 | Not Limited | > 75 | 70.5 | 14 | Not Limited | > 75 | 62 | 13 |
| 70 | Not Limited | > 75 | 92.5 | 17 | Not Limited | > 75 | 81 | 16 |
| 75 | Not Limited | > 75 | 137 | 23 | Not Limited | > 75 | 120 | 21 |
CONTACT:
Chris VanDyke
Research Scientist | Program Manager
chrisvandyke@uky.edu
