Developing a Computer Program for the Methods of Radius-Estimating Techniques for Horizontal Curves

Abstract

Problem statement: This study discusses the development of computer software of two phases. First phase contains the calculations of all curve elements of the four types of the horizontal curve and second phase contains the modeling of the ten methods of estimating the radius of the horizontal curve. Approach: The program is named as HCRET, which stands for Horizontal Curves and Radius Estimating Techniques. The program is written in Visual Basic-Version 6 language. The developed program deals with the calculation of all elements of the horizontal curve of the four types of the horizontal curves, which consists of simple, compound, reverse and transition. Results: The program also used for modeling of the ten methods of radius-estimating of horizontal curve, which consist of Ball Bank Indicator, Chord Length, Compass, Lateral Acceleration, Plan Sheet, Advisory Speed Plate, Modified Yaw Rate, Field Survey, and Global Positioning System for the calculation of estimated-radius. The program output is comprehensive and easy to understand, while the program input is used friendly and provided with many graphical objects to facilitate ease of use. A case study of three examples presented to evaluate the modeled software of three horizontal curves. Two curves were located in university of Baghdad and a third curve was designed and includes also the experimental work of radius-estimating methods of horizontal curves as follow field survey, plan sheet, compass, Global Positioning System (GPS). Conclusion/Recommendations: The results that obtained of the three curves by using the radius-estimating methods include the true and estimated radius of each method. The field survey and the plan sheet method provided the most accurate result 0.8002 and 0.8660 respectively. The plan sheet method and GPS method is preferred, because plan sheets are easily accessible to these users and GPS is the accurate field method. While the compass method is not the accurate, it is easy to use, and has a low cost.