18.2.2.2.2. Case 2 Length of valley curve less than stopping sight distance (L<S)

Try these first

1. 1.

   What does L represent in the context of valley curves?

   Hint

   Think about what distance is crucial in road design.

2. 2.

   What is Stopping Sight Distance (SSD)?

   Hint

   Consider how far a vehicle can travel after a driver reacts.

3. 3.

   What is the formula for calculating the length L of a valley curve when L is less than SSD?

   • L = 2S - N
   • L = S/N
   • L = N/2

   Hint

   Think about how we derive L from S and N.

4. 4.

   True or False: The length of a valley curve can be less than the stopping sight distance without safety implications.

   • True
   • False

   Hint

   Consider the effects on driver reactions.

5. 5.

   Your road design includes a valley curve with an estimated sight distance of 80m and a deviation angle of 4m. Calculate L and analyze its implications on road safety.

   Hint

   Be mindful of the total curve extent.

6. 6.

   A rural road design shows a valley curve length of 100m while SSD required is 90m. Discuss potential safety issues with this design.

   Hint

   Consider factors like speed limits and gradient changes.