I'm developing a company standard SEP file. I'm having difficulty with the equations for Superelevation Runoff and Tangent Runout. I'm wondering where the equations came from? They're not familiar to me and do not match AASHTO GDHS Equations 3-23 & 3-24. I'm trying to validate the provided equations and without knowing where it came from, it is difficult. I think I can use the intrinsic variables to come up with an appropriate value. When I calculate with the current equations, I am not getting the desired results.
The SEP Preference File Settings Manual indicates the equations are as follows:
RUNOFF LENGTH
= (0.24 * ((0.0571 * (Vd * Vd)) - (4.84 * Vd) + 306.74)) + ((Wn * 2) * ((e - 2)/100) * ((0.0571 * (Vd * Vd)) - (4.84 * Vd) + 306.74))
RUNOUT LENGTH
= (0.24 * ((0.0571 * (Vd * Vd)) - (4.84 * Vd) + 306.74))
WITH INTRINSIC VARIABLES:
PowerGEOPAK V8i (SELECTseries4) Version 08.11.09.878
Thank you for your help,
Joe