If the required e is less than e_max, you proportionally shorten L_r:
While I cannot directly provide a file here, you can build your own in 20 minutes using the formulas above. For a ready-to-use version, search for “AASHTO 2018 superelevation excel sheet” on engineering forums or GitHub. Many DOTs (e.g., Florida, Texas, Virginia) publish free spreadsheets on their websites.
Thus:
The first step is to establish the fixed parameters for the specific road section. These values are typically governed by standards like or local DOT manuals. Design Speed ( The intended speed of the road (e.g., Radius of Curve ( The sharpness of the curve. Maximum Superelevation ( e sub m a x end-sub Usually capped at depending on climate (ice/snow) and terrain. Normal Crown ( e sub n c end-sub The standard slope for drainage (typically Lane Width ( The width of the travel lane. 2. Calculate Required Superelevation (
A functional is more than just a single formula. It acts as a mini-calculation engine. Below are the essential input and output sections you must include. superelevation calculation excel sheet
Where:
This article provides a deep dive into the theory, formulas, and step-by-step construction of a . By the end, you will have a working template that computes design rates, checks friction demand, and transitions lengths (superelevation runoff). If the required e is less than e_max,
= (B2^2) / (127 * C2) - G2
Add a dropdown to select method. For Method 1, lane cross slopes change sign during transition; your sheet can compute left vs. right edge elevations. Thus: The first step is to establish the
Add data validation to restrict inputs (e.g., max superelevation between 2% and 10%).