WONDER #1947: How Does a Traffic Light Work?

Question 1 of 3

Which type of traffic signal sensor uses a coil of wire embedded in the road surface?

  1. video
  2. radar
  3. inductive loop
  4. weight

Question 2 of 3

In areas with consistent, heavy traffic, signals may simply run on what?

  1. timers
  2. sensors
  3. flyers
  4. solos

Question 3 of 3

Which of the following is NOT a type of vehicle that might use a traffic signal preemption system?

  1. ambulance
  2. fire truck
  3. police car
  4. dump truck

Check your answers online at https://www.wonderopolis.org/wonder/how-does-a-traffic-light-work.