Gridlock

Gridlock is a form of traffic congestion where 'continuous queues of vehicles block an entire network of intersecting streets, bringing traffic in all directions to a complete standstill'. The term originates from a situation possible in a grid plan where intersections are blocked, preventing vehicles from either moving forwards through the intersection or backing up to an upstream intersection. Gridlock is a form of traffic congestion where 'continuous queues of vehicles block an entire network of intersecting streets, bringing traffic in all directions to a complete standstill'. The term originates from a situation possible in a grid plan where intersections are blocked, preventing vehicles from either moving forwards through the intersection or backing up to an upstream intersection. The term gridlock is also used incorrectly to describe high traffic congestion with minimal flow (which is simply a traffic jam), where a blocked grid system is not involved. By extension, the term has been applied to situations in other fields where flow is stalled by excess demand, or in which competing interests prevent progress. Traditional gridlock is caused by cars entering an intersection on a green light without enough room on the other side of the intersection at the time of entering to go all the way through. This can lead to the car being trapped in the intersection when the light turns green in the other direction. If the same situation occurs simultaneously in multiple intersections, these cars can be trapped in the intersections indefinitely. In many jurisdictions, drivers are therefore prohibited from entering an intersection at a green light if there is no room for them to clear the intersection. If all drivers follow this rule, gridlock is impossible.