Which of these is NOT correct with respect to percentile speed on highways ?
1
Upper safe speed limit for regulation of traffic on highway is 85th percentile speed.
2
For the purpose of highway geometric design, the percentile speed adopted is 90th percentile speed.
3
The difference between 85 percentile speed and 15 percentile speed gives quality of flow.
4
Minimum speed limit adopted on highway is 15th percentile speed.