traffic congestion

Congested Times Square in Midtown Manhattan, New York City, which leads the world in urban automobile traffic congestion, but which has implemented congestion pricing in January 2025 to address the issue

Traffic congestion is a condition in transport that is characterized by slower speeds, longer trip times, and increased vehicular queuing. Traffic congestion on urban road networks has increased substantially since the 1950s, resulting in many of the roads becoming obsolete. When traffic demand is great enough that the interaction between vehicles slows the traffic stream, this results in congestion. While congestion is a possibility for any mode of transportation, this article will focus on automobile congestion on public roads. Mathematically, traffic is modeled as a flow through a fixed point on the route, analogously to fluid dynamics.