Review of maximum superelevation utilized in current method provided in highway design
The American Association of State Highway and Transportation Officials (AASHTO) provides Method 5 for recommendation for horizontal design of curves for rural highways and high speed urban street facilities. Method 5 deals with balancing superelevation and side friction factors and provides complex mathematical calculation that results in design inconsistencies due to utilization of various maximum superelevations throughout different states in the United States. This thesis identifies the design discrepancies when different maximum superelevations are used and proposes a simple solution and analysis of the solution for this geometric design problem. The proposed recommendation encompasses the use of one single maximum superelevation value that decreases vehicle driver work load and improves safety. Tables and graphs are provided for analyzing the provided solution in different aspects and the benefits from the proposed solution.