Fluid flow models are used to study the interaction of vehicles on existing (and planned) road infrastructure in order to optimize flow through cities, towns and highways. The studies are often subject to a number of criteria such as acceptable journey times, CO2 emissions and so on. In this example we are concerned with density, speed and vehicular density models.
Macroscopic fluid traffic flow models can be used to investigate queue buildups. This work is a theoretical (and numerical) example using scalar non-linear physical models to quantify variations in traffic conditions (density, speed, flux). These pages exemplify the theory using four common road phenomena, a long road stretch, traffic lights, junctions and a roundabout.