Abstract:
In practice, the task of designing the horizontal alignment of a highway is done manually
based on experience and engineering judgement. As a result, the work is both time and
resource consuming and relies heavily on human expertise. This paper presents a general
formulation for optimization of horizontal alignment, composed of tangential segments and
circular curves. It consists of a constrained optimization problem where the objective
function is to minimize the overall cost of the horizontal alignment. These constraints are
imposed by curvatures, geometric guidelines, the presence of inaccessible regions, etc. In
addition to construction costs, facts considered by this model also include highway geometric
code requirements. The paper mainly focuses on fitting the curves with appropriate radius
between the tangential sections obtained by connecting the optimum set of point of
intersections (Pis). The available methods consider radius of the curves as a constant value,
which also acts as a constraint while developing an optimal alignment. Application of the
model to a real-world study area is also presented in this paper, along with a comparative
study with AutoCAD Civil-3D.
