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

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