Question

As per the IRC recommendations, the coefficient of friction to be preferred between the road surface and vehicle tyre for a speed of vehicle about 50 kmph is .........

• A. 0.37
• B. 0.36
• C. 0.35
• D. 0.34

Hint:

As speed increases, the recommended coefficient of friction decreases due to reduced tire-road interaction—always refer to the latest IRC standards for updates.

Answer 1

The Correct Option is A

Step 1: Understand the context
The coefficient of friction between a road surface and a vehicle tyre is a critical factor in highway design. It influences braking distance and sight distance.
Step 2: Refer to IRC standards
IRC (Indian Roads Congress) provides recommended values of the longitudinal coefficient of friction (f) for different design speeds.
Step 3: Look up the value for 50 kmph
According to the IRC, for a vehicle speed of about 50 kmph, the recommended value of the coefficient of friction is 0.37.
Step 4: Eliminate incorrect options
- 0.36 is slightly lower than the standard and used for slightly higher speeds.
- 0.35 and 0.34 are applicable at even higher speeds (e.g., 80+ kmph).
Step 5: Final Answer
Hence, the correct coefficient of friction to be used for 50 kmph as per IRC is 0.37.