The City has a few fixed-time signals, primarily in construction areas. These signals assign most of the available green time in a cycle to the heaviest traffic movement.
Many drivers ask why they have to wait so long for a signal to change.
Many of these drivers are waiting to enter a major arterial street from a side street. This is even more frustrating when no traffic can be seen on the arterial. In order to coordinate arterial traffic signals, each traffic signal in the group needs to allow sufficient green time for all movements during a common fixed time period, called a common cycle length. The cycle length chosen is usually determined by the largest intersection in a group of signals with the most conflicting movements. This will most often be an intersection that has left-turn arrows for all directions and wide cross streets.