Transportation has continuously evolved to meet the increasing demand for safe, efficient, and convenient travel. The development of highways has significantly improved connectivity between locations; however, the rise in vehicle speed and traffic volume has also increased the risk of road accidents and traffic congestion, particularly at intersections. One effective solution to these challenges is the construction of rotary (roundabout) intersections, which help regulate traffic flow, minimize conflict points, reduce accident rates, and provide safer crossing opportunities for pedestrians.

This study focuses on the geometric design of a rotary intersection using AutoCAD Civil 3D software and compares the process with conventional manual design methods. The objective is to demonstrate that Civil 3D enables faster, more accurate, and cost-effective intersection design while producing reliable engineering reports. In contrast, manual design requires more time, greater effort, and is more prone to errors.

AutoCAD Civil 3D integrates design, drafting, and 3D visualization into a single platform, allowing engineers to efficiently create, modify, and analyze highway intersection layouts. The software supports the preparation of earthwork reports, 3D models, and design alternatives for both small- and large-scale infrastructure projects, resulting in reduced project time and cost. Its advanced visualization capabilities also improve design understanding and decision-making during project planning.

A rotary intersection is a type of at-grade intersection in which vehicles circulate around a central island in a single direction. Under left-hand traffic conditions, approaching vehicles enter the rotary, travel around the central island, and exit smoothly toward their intended destinations. Proper geometric design of such intersections enhances traffic efficiency, improves road safety, and ensures economical construction. This study highlights the practical application and advantages of AutoCAD Civil 3D in designing modern rotary intersections for highway engineering projects.

Keywords: AutoCAD Civil 3D, Rotary Intersection, Geometric Design, Highway Engineering, 3D Modeling, Earthwork Report.