# Find Headlight And Intermediate Sight Distance – Mathematical Problem And Solution

8th April 2019## Find Headlight And Intermediate Sight Distance

Here, a mathematical problem is taken to determine the value of headlight sight distance and intermediate sight distance, when the value of the design speed is given.

### Mathematical Problem

Find headlight sight distance and intermediate sight distance for a design speed of 65 Km/h (Use f=0.36, t=2.5 sec)

### Mathematical Solution

Design speed = 65 Km/h = 18 m/sec

Now,

**Stopping Sight Distance** (SSD) =( vt + v**^{2}**/2gf ) = 18⨯2.5+ 18

**/(2⨯9.81⨯0.36) = 91m.**

^{2}**Another way,** when design speed is taken as 65 Km/h.

SSD = (0.278V.t + V²/254f) = 0.278⨯65⨯2.5 + 65**^{2}**/254⨯0.36 = 91m so,

- Headlight Sight Distance(HSD) = SSD = 91m
- Intermediate Sight Distance(ISD) = 2(SSD) =2⨯91=182m

*Read Also:*

How to Calculate Stopping Sight Distance – Mathematical Example