18.2.2.2. Safety criteria

Try these first

1. 1.

   What does the abbreviation SSD represent in road design?

   Hint

   Think about what distance drivers need to stop.

2. 2.

   True or False: Valley curves are always straight.

   Hint

   Recall the shape formed by gradients.

3. 3.

   What is the primary concern of safety criteria for valley curves?

   • Comfort of passengers
   • Visibility for drivers
   • Design speed

   Hint

   Think about what makes a road safe.

4. 4.

   True or False: Valley curves only need to be considered during the day.

   • True
   • False

   Hint

   When do headlights come into play?

5. 5.

   A valley curve is proposed for a new road section. The expected stopping sight distance is 150m. Calculate the necessary conditions if the valley curve is to be designed shorter than SSD. Discuss the implications on safety.

   Hint

   Consider how the light reaches different parts of the curve.

6. 6.

   Given a scenario where a road needs to accommodate higher traffic speeds, what adjustments would you make to both the valley curve length and the safety criteria?

   Hint

   How does speed relate to stopping distance?