14.6. Problems

Try these first

1. 1.

   What is centrifugal force?

   Hint

   Think about the direction of forces when a vehicle is turning.

2. 2.

   Define super-elevation.

   Hint

   What happens to the outer edge of the road on a curve?

3. 3.

   What does centrifugal force depend on?

   • Weight of the vehicle
   • Design speed and radius
   • Frictional resistance

   Hint

   Consider the forces acting on the vehicle when going through a curve.

4. 4.

   True or False: Super-elevation increases the risk of skidding.

   • True
   • False

   Hint

   Think about the purpose of super-elevation on curves.

5. 5.

   A highway curve has a radius of 80 meters. What is the maximum speed a vehicle can safely travel without skidding if the coefficient of friction is 0.15?

   Hint

   Use the friction and gravity to calculate the maximum allowable speed.

6. 6.

   Design a road curve for a speed of 60 km/h with a radius of 50 m. Calculate the required super-elevation.

   Hint

   Ensure to convert units properly and remember to account for the friction.