JUSTIFICATION OF DESIGN SOLUTIONS FOR THE CONSTRUCTION OF A TRANSPORT INTERCHANGE UNDER DENSE URBAN DEVELOPMENT CONDITIONS: THE CASE OF SHYMKENT CITY

Abstract

Rapid urbanization and continuous growth in motorization require comprehensive approaches to selecting transport interchange design solutions in densely developed urban areas, where traffic, spatial, and economic constraints must be considered simultaneously. The aim of this study is to justify the optimal design solution for a transport interchange at the intersection of Zhibek Zholy and Sairamskaya Streets in Shymkent, Kazakhstan. The research methodology included a review of international experience and regulatory requirements, field traffic surveys, assessment of existing planning and geometric constraints, traffic demand forecasting, and comparative evaluation of alternative engineering solutions. Two interchange configurations were developed and assessed: a two-level scheme with flyovers and turnaround ramps, and a three-level configuration incorporating an intermediate roundabout. The results demonstrate that the first alternative leads to overloading of individual interchange elements, requires additional demolition of surrounding buildings, and involves substantially higher construction costs. In contrast, the second alternative provides sufficient traffic capacity under projected demand, distributes traffic flows more efficiently, minimizes impacts on the surrounding urban environment, and reduces overall construction costs. The study concludes that a compact three-level interchange with an intermediate roundabout represents the most balanced engineering solution for densely built urban areas by effectively integrating transport performance, spatial feasibility, and economic efficiency. The proposed approach can support transport infrastructure planning and decision-making in rapidly developing cities.