Modeling the Motion of a Single Vehicle

The movement of a single vehicle is a fundamental building block in traffic modeling. A single vehicle can significantly impact the performance of a traffic stream. Consider an on-ramp vehicle entering a busy freeway at a low speed: it can cause freeway mainline vehicles to abruptly change lanes, which – for the right amount of traffic – may lead to severe congestion and stop-and-go traffic. Consider also a slow-moving truck at the front of a long line of vehicles traveling behind it with no passing opportunities: the performance of this truck significantly affects the speed and travel time of the following vehicles. Understanding the characteristics, performance, and movement of each vehicle allows us to model groups of vehicles and estimate the performance of the traffic stream. Furthermore, the movement of individual vehicles allows us to develop better highway design and traffic control solutions. For example, understanding the acceleration and deceleration constraints of various vehicle types can help us design more effective passing zones and allocate appropriate yellow and all-red intervals at signalized intersections.