18.2.2.2.1. Case 1 Length of valley curve greater than stopping sight distance (L>S)

Try these first

1. 1.

   What defines a valley curve?

   Hint

   Think about the shape and purpose of road curves.

2. 2.

   What do we consider when determining headlight sight distance?

   Hint

   Relate the question to night driving conditions for clarity.

3. 3.

   What condition must the length of a valley curve satisfy when it exceeds the stopping sight distance?

   • The curve must have an infinite radius.
   • The sight distance is minimum at the lowest point.
   • The headlight beam must have a height less than S.

   Hint

   Think about where visibility would be lowest on the curve.

4. 4.

   True or False: A valley curve provides more comfort for passengers when designed appropriately.

   • True
   • False

   Hint

   Consider how passengers react to smooth rides.

5. 5.

   Considering a valley curve with specific gradients, calculate both the comfort and safety lengths and determine the most appropriate design for SSD.

   Hint

   Ensure all parameters used in your calculations are aligned with your scenario.

6. 6.

   Analyze the impact of improper valley curve design in terms of accident statistics and passenger comfort.

   Hint

   Draw data from real-world scenarios to support your argument.