If R is the radius of the main curve, θ is the angle of deflection, S is the shift and L is the length of the transition curve, then total tangent length of the curve is:
1
(R + S) tanθ / 2 - L / 2
2
(R + S) tanθ / 2 + L / 2
3
(R - S) tanθ / 2 - L / 2
4
(R - S) tanθ / 2 + L / 2
5
None of these