Description

This paper analyzes the microscopic speed and acceleration characteristics of heterogeneous traffic streams on multilane divided highways in India. Understanding acceleration profiles, maximum achievable speeds, and deceleration behavior is essential for micro-simulation modeling, geometric design of acceleration/deceleration lanes, passing zone design, and safety evaluations. High-frequency trajectory data and speed profiles were captured across multi-lane test sections using video image processing and GPS tracking for various vehicle types, including motorized two-wheelers, passenger cars, buses, and multi-axle trucks under varying gradient and traffic conditions. The study establishes probability distributions for operating speeds and models acceleration capabilities as a function of initial speed, vehicle power-to-weight ratio, and roadway gradient. The empirical results demonstrate significant disparities in acceleration capabilities between light passenger vehicles and heavily loaded commercial vehicles, which create severe speed differentials and lane-sorting turbulence in mixed traffic streams. The paper formulates non-linear acceleration models suitable for incorporation into modern microscopic traffic simulation software (such as VISSIM and AIMSUN) customized for Asian traffic conditions. These models assist engineers in optimizing merge length designs, climbing lanes, and highway junction layouts to enhance both operational efficiency and traffic safety.