Practice question

In arterial signal timing, what is the purpose of slotting?

  1. To define the color of pedestrian signals.
  2. To allocate green time to different phases in a cycle to match demand.
  3. To set the cycle length to a fixed value.
  4. To assign lane usage by time of day.

Answer: B — To allocate green time to different phases in a cycle to match demand.

Slotting is the allocation of green time within the signal cycle to the different movements (phases) based on demand. By dividing the cycle into time slots, engineers give busier approaches longer green periods and lighter ones shorter ones, balancing throughput and reducing overall delay while keeping safety constraints like minimum green and clearance times. This approach helps coordinate progression along the arterial and respond to varying traffic volumes. It isn’t about the color of pedestrian signals, nor about fixing the cycle length itself, nor about assigning lanes by time of day.

Practice more: ITE Traffic Bowl Fundamentals and Engineering Practice Test →