Traffic light control and coordination

The normal function of traffic lights requires more than sight control and coordination to ensure that traffic and pedestrians move as smoothly, and safely as possible. A variety of different control systems are used to accomplish this, ranging from simple clockwork mechanisms to sophisticated computerized control and coordination systems that self-adjust to minimize delay to people using the junction.

In the United States, traffic signal timing is traditionally operated to minimize vehicle delay at traffic signals. This often impacts safety and mobility for people walking and riding bicycles.