gridlock

Gridlock is a traffic condition in which road networks become so congested that vehicles cannot move effectively, often at or near intersections, causing widespread delays. The term comes from a situation where the streets form a grid and vehicles are blocked by jams that prevent both cross-traffic and through-traffic from advancing. The phrase is also used in political contexts to describe an impasse in a legislative process.

Causes of traffic gridlock include excessive demand relative to road capacity, bottlenecks at merges or intersections, road work or accidents, and poor traffic management such as poorly timed signals. In a dense urban grid, initial congestion at a single point can propagate as queues back up through multiple intersections, creating a self-reinforcing standstill.

Impacts include longer travel times, increased fuel consumption and emissions, reduced reliability of transit, higher costs for businesses, and greater frustration and safety risks for motorists and pedestrians. Gridlock is more common in cities with high car ownership, limited alternative transport options, and where demand outpaces infrastructure growth.

Mitigation strategies focus on reducing demand, increasing mobility options, and improving network efficiency. Approaches include congestion pricing, expanded or prioritized public transit, incident management, synchronized or adaptive signal timing, curbside management, and infrastructure projects that remove bottlenecks or provide alternative routes. Urban planning that favors dense, walkable neighborhoods and multimodal access can reduce susceptibility to gridlock over the long term. In political discourse, gridlock is used to describe legislative stalemate where action is blocked by conflicting interests.