What is the term for the situation when a road is overused and traffic cannot move freely?

Traffic congestion refers to a condition on road networks that occurs when vehicle demand exceeds road capacity, leading to slower speeds and increased density of vehicles. It describes a scenario where roads become overused, resulting in significant delays and hindrance to the free movement of traffic. This phenomenon can be caused by various factors, such as high vehicle volumes, road works, accidents, or even weather conditions.

Although terms like 'traffic jam' and 'gridlock' may describe narrow instances within the broader concept of traffic congestion, they do not encompass the entirety of the situation. A traffic jam specifically refers to a temporary blockage that can cause backlogs of vehicles, whereas gridlock often pertains to a situation where vehicles are unable to move at all, commonly at intersections. Ultimately, traffic congestion is the most accurate term to describe the ongoing issue of road overuse that results in a general slowdown of traffic flow.