Change the traffic light systems. Most traffic lights are timed and designed to respond in an optimal way to average traffic patterns. The problem is that there typically are not any average patterns. Traffic volume varies greatly no matter what day or time it is. If too many vehicles have to wait at red lights for too long, it can lead to traffic congestion and gridlock. Traffic lights that are designed to respond to underground sensors when a car is actually present, as opposed to those run by automatic timers, can decrease waiting times at red lights.