Study on the Relationship Between Speed and Flow for Highway Traffic Management

The problems associated with mixed traffic conditions on urban streets in developing countries are distinct and complex. Pedestrians, bicycles, buses, cars, motorcycles, auto-rickshaws, and various other modes share the same roadway space, creating operational inefficiencies that negatively impact mobility and reduce the economic productivity of urban areas. Rapid growth in motor vehicle ownership has further intensified congestion, making traffic flow management more challenging than ever. Understanding fundamental traffic flow characteristics—particularly the relationships between speed, flow, and density—is essential for effective planning, design, and operation of urban transportation systems. Traffic flow theory provides the analytical framework for quantifying these relationships under varying roadway and traffic conditions. Although numerous models have been proposed by researchers worldwide, many exhibit limitations when applied to heterogeneous traffic environments dominated by non-lane-based movement. In this study, mathematical models describing the speed–flow relationship under mixed traffic conditions were developed for selected urban corridors in Vijayawada city. Using detailed field observations, speed–flow equations were formulated, and the capacity of each road section was subsequently estimated. The findings offer valuable insights for urban traffic management, roadway capacity evaluation, and strategic planning in cities experiencing heterogeneous traffic patterns.