14.1. A transition curve of the cubic parabola type

Try these first

1. 1.

   What is the formula for calculating tangent length?

   Hint

   Recall the relationship between radius and deflection angle.

2. 2.

   Define what a transition curve is.

   Hint

   Think about road design.

3. 3.

   What is a transition curve used for?

   • To smoothen curves
   • To connect straight roads
   • Both

   Hint

   Reflect on the design principles.

4. 4.

   True or False: The radius (R) of a cubic parabola can affect the tangent length.

   • True
   • False

   Hint

   Think of the relationships between the parameters.

5. 5.

   Given a transition curve with a radius of 400 m and a desired offset of 3 m, calculate the necessary tangent length.

   Hint

   Apply the formula T = sqrt(R^2 - Offset^2).

6. 6.

   Calculate the deflection angle required if you are setting a curve with a radius of 250 m and a chord length of 60 m.

   Hint

   Break down the parts of the circular definitions.