This document describes a density-based dynamic traffic signal system that uses image processing of traffic scenes to determine vehicle density at a junction and automatically adjust signal timing accordingly. It notes that conventional fixed-time traffic signals cannot adapt to changing traffic conditions. The proposed system would use a Raspberry Pi microcontroller and camera to capture images of each side of the junction, process the images to count vehicles, determine which side has higher density, and allot longer green signal time to that side to reduce congestion and waiting times. It discusses limitations like impacts of stationary vehicles and proposes using a combined metric of density and flow to provide a more informative measure of congestion for adaptive traffic control.