Find The Stopping Sight Distance To Avoid Head-on Collision
Here, a mathematical problem is taken to determine the value of minimum stopping sight distance to avoid head-on collision of two cars, when the value of the braking efficiency is given.
Find minimum stopping sight distance to avoid head-on collision of two cars approaching at 90 Km/h and 60Km/h. Use reaction time 2.5 sec, coefficient of longitudinal friction is 0.7 and brake efficiency of 50 percent in either case.
- V1 = 90 Km/h
- V2 = 60 Km/h
- t = 2.5 sec
- f = 0.7
- Braking efficiency (η) =50% =0.5( note: brake efficiency reduces the coefficient of friction by 50%)
Now, Stopping Sight Distance of first car
(SSD1) = (0.278V.t + V²/254fη)
= 0.278⨯90⨯2.5 + 90²/254⨯0.7⨯0.5
Stopping Sight Distance of second car
(SSD2) = (0.278V.t + V²/254fη)
= 0.278⨯60⨯2.5 + 60²/254⨯0.7⨯0.5
So, Stopping Sight Distance to avoid head-on collision of the two approaching cars
(SSD) = SSD1 + SSD2