Automatically generated from TS_sta.
The transition from a flat road to a banked curve occurs over two distances: Tangent Runout Superelevation Runoff Superelevation Runoff ( cap L sub r The length needed to rotate the outer lane from a slope to the full design superelevation ( = Lane width. = Number of lanes rotated. = Adjustment factor for number of lanes. = Maximum relative gradient. Tangent Runout ( cap L sub t
Creating a from scratch is a great way to master the concept. Here is the logic flow to set up in Excel. superelevation calculation excel sheet
A powerful feature: given curve start station (TS) and curve end station (ST), your sheet can automatically compute:
When a vehicle negotiates a horizontal curve of radius ( R ) (meters or feet) at design speed ( V ) (km/h or mph), the required superelevation rate ( e ) (in m/m or ft/ft) is derived from equilibrium: Automatically generated from TS_sta
AASHTO recommends horizontal curve length > 2× runoff length. Add a validation:
$$e + f = \fracV^2gR$$
Use simple arithmetic in columns.