- Passing sight distance is the length of roadway downstream a motorist must be able to see to safely complete a passing maneuver. Safe completion means the motorist does not cut off the vehicles they are passing before they meet a vehicle coming from the opposing direction. Table 5.5 lists passing sight distances for design speeds between 20 mph and 80 mph.
| Table 5.5 Passing Sight Distances | |||
| Design Speed (mph) | Assumed Speeds (mph) | Passing Sight Distance (ft) | |
| Passed Vehicle | Passing Vehicle | ||
| 20 | 8 | 20 | 400 |
| 25 | 13 | 25 | 450 |
| 30 | 18 | 30 | 500 |
| 35 | 23 | 35 | 550 |
| 40 | 28 | 40 | 600 |
| 45 | 33 | 45 | 700 |
| 50 | 38 | 50 | 800 |
| 55 | 43 | 55 | 900 |
| 60 | 48 | 60 | 1,000 |
| 65 | 53 | 65 | 1,100 |
| 70 | 58 | 70 | 1,200 |
| 75 | 63 | 75 | 1,300 |
| 80 | 68 | 80 | 1,400 |
- Regardless of how much passing sight distance is available, the main problem is that motorists tend to misjudge the amount of time they have to execute a passing maneuver once the see a vehicle coming from the opposite direction. Design elements that control speed and improve a motorist’s ability to judge the speed of oncoming vehicles will have the most positive impact.
CONTACT:
Chris VanDyke
Research Scientist | Program Manager
chrisvandyke@uky.edu
