Highway Cross-sectional Elements - IES Previous Year Questions
11.  A vehicle moving at 40 kmph speed was stopped by applying brakes and the length of the skid marks was 12.2 m. If the average skid resistance of the pavement is 0.70, the brake efficiency of the test vehicle will be nearly _____ .
[IES 2019]
- 80%
- 74%
- 68%
- 62%
Answer: Option B
Explanation:
Vehicle speed, v = 40 kmph = 11.11 m/s
The average skid resistance coefficient (f) can be calculated using the below formulae:
f =
Using the expression, fobtained =
⇒ fobtained = 0.516
Thus, Braking efficiency, η =
⇒ η = 73.7%
Explanation:
Vehicle speed, v = 40 kmph = 11.11 m/s
The average skid resistance coefficient (f) can be calculated using the below formulae:
f =
a / g
, 2L / gt2
, v2 / 2gL
Using the expression, fobtained =
v2 / 2gL
= 11.112 / 2 x 9.81 x 12.2
⇒ fobtained = 0.516
Thus, Braking efficiency, η =
fobtained / faverage
x 100% = 0.516 / 0.70
x 100% ⇒ η = 73.7%
12.  Which one of the following are provided to give access to properties along an important highway with controlled access to expressway or freeway ?
[IES 2021]
- Lay-bys
- Frontage roads
- Driveways
- Cycle tracks
Answer: Option B
Explanation:
Explanation:
- Frontage roads provide access to the properties along an important highway.
- Driveways provide access to commercial establishments like fuel-stations along the highway.