Automated Design of Interchange Horizontal Alignment Based on Genetic Algorithm

The design of interchanges is one of the key factors for highway alignment design. The current research on the alignment design of interchange focuses on algorithmic optimization of parameters based on existing scheme design. The use of computers to achieve semi-automated alignment design work still consumes a lot of labor and resources in the early stage of the design of the preliminary scheme. Therefore, this study proposes an automated procedure for designing horizontal alignment of highway interchanges. A database with an inquiry function of interchange alignment parameters was established using existing cases. A model for calculating the parameters of horizontal alignments and an automation model were constructed. The optimization results of this model were solved using the genetic algorithm and the alignment was plotted in AutoCAD. Finally, the effectiveness of the proposed approach was demonstrated in a real-world case study that designed an interchange in Yuanshanzi Village, Gansu, China. The comprehensive evaluation of horizontal alignment costs and vertical alignment optimization showed improvements, with the fitness function value of the automated scheme improving by 22% over the manual design. This study developed a database and innovatively combined the database with an alignment optimization model. To address challenges in the design process, the starting point trial algorithm and the third endpoint constraint calculation method were proposed, thereby achieving a fully automated design workflow that includes preliminary scheme generation. This approach significantly reduces manual work during the preliminary design phase and provides a novel theoretical and technical framework for automated interchange alignment design.