15.4. Extra Widening

Try these first

1. 1.

   What is extra widening in road design?

   Hint

   Think about how roads differ in straight versus curved areas.

2. 2.

   Define mechanical widening.

   Hint

   Consider the paths of front and rear wheels.

3. 3.

   What is extra widening?

   • a) Width added on straight section
   • b) Width needed for curves
   • c) Width of road shoulders

   Hint

   Think about how intersections differ from curves.

4. 4.

   True or False: Off-tracking occurs when a vehicle’s rear wheels follow a shorter path than the front wheels.

   • True
   • False

   Hint

   Consider the movement pattern of vehicles around corners.

5. 5.

   Calculate the total extra width required for a road curve with a radius of 300m, design speed of 60 km/h, and two lanes, considering both mechanical and psychological factors.

   Hint

   Utilize the formulas given in class to derive your solution.

6. 6.

   Design a curve scenario for a highway. Illustrate the importance of addressing extra widening while considering high-speed vehicles and heavy trucks.

   Hint

   Refer to IRC guidelines for maximum permissible widenings.