CO Traffic Signal Technician Exam
Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary purpose of a traffic signal system at an
intersection?
A. To increase vehicle speed
B. To eliminate pedestrian crossings
C. To control conflicting movements and improve orderly traffic flow
D. To eliminate the need for traffic signs
Answer: C. To control conflicting movements and improve orderly
traffic flow
,Rationale: Traffic signals are designed primarily to assign right-of-way
among conflicting vehicle, bicycle, and pedestrian movements. Proper
signal operation reduces conflicts and helps traffic move through an
intersection in an organized manner.
2. Which component is responsible for controlling the sequence and
timing of traffic signal indications?
A. Pull box
B. Signal controller
C. Detector loop
D. Signal head
Answer: B. Signal controller
Rationale: The signal controller is the central control device that
determines when green, yellow, and red indications are displayed. It
operates according to programmed timing and control parameters.
3. What color indication normally means that a vehicle must stop
and remain stopped?
A. Green
B. Yellow
C. Flashing yellow
D. Red
,Answer: D. Red
Rationale: A steady red indication requires traffic to stop before
entering the intersection, subject to applicable traffic laws governing
permitted turns or other exceptions.
4. What is the primary purpose of the yellow signal interval?
A. To provide additional green time
B. To warn that the green interval is ending and the red indication is
approaching
C. To allow pedestrians to cross without restriction
D. To reset the controller
Answer: B. To warn that the green interval is ending and the red
indication is approaching
Rationale: The yellow interval provides a transition between green
and red. It warns approaching road users that the right-of-way is
ending and that they should prepare to stop when it is safe to do so.
5. Which device detects vehicles using changes in inductance caused
by a vehicle passing over a roadway loop?
A. Photocell
B. Inductive loop detector
, C. Radar reflector
D. Pedestrian push button
Answer: B. Inductive loop detector
Rationale: An inductive loop detector uses wire embedded in or
installed beneath the pavement. A vehicle's metallic mass changes the
loop's electromagnetic characteristics, allowing the detector unit to
identify vehicle presence.
6. What is a common function of a pedestrian push button?
A. It changes the traffic signal to flashing operation permanently
B. It requests a pedestrian crossing phase
C. It measures vehicle speed
D. It controls streetlight voltage
Answer: B. It requests a pedestrian crossing phase
Rationale: Pedestrian push buttons allow pedestrians to place a
crossing call with the signal controller. The controller then
incorporates the pedestrian phase according to its programmed
timing and operational requirements.
7. Which signal indication generally permits a movement when
conditions are otherwise safe and lawful?
Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary purpose of a traffic signal system at an
intersection?
A. To increase vehicle speed
B. To eliminate pedestrian crossings
C. To control conflicting movements and improve orderly traffic flow
D. To eliminate the need for traffic signs
Answer: C. To control conflicting movements and improve orderly
traffic flow
,Rationale: Traffic signals are designed primarily to assign right-of-way
among conflicting vehicle, bicycle, and pedestrian movements. Proper
signal operation reduces conflicts and helps traffic move through an
intersection in an organized manner.
2. Which component is responsible for controlling the sequence and
timing of traffic signal indications?
A. Pull box
B. Signal controller
C. Detector loop
D. Signal head
Answer: B. Signal controller
Rationale: The signal controller is the central control device that
determines when green, yellow, and red indications are displayed. It
operates according to programmed timing and control parameters.
3. What color indication normally means that a vehicle must stop
and remain stopped?
A. Green
B. Yellow
C. Flashing yellow
D. Red
,Answer: D. Red
Rationale: A steady red indication requires traffic to stop before
entering the intersection, subject to applicable traffic laws governing
permitted turns or other exceptions.
4. What is the primary purpose of the yellow signal interval?
A. To provide additional green time
B. To warn that the green interval is ending and the red indication is
approaching
C. To allow pedestrians to cross without restriction
D. To reset the controller
Answer: B. To warn that the green interval is ending and the red
indication is approaching
Rationale: The yellow interval provides a transition between green
and red. It warns approaching road users that the right-of-way is
ending and that they should prepare to stop when it is safe to do so.
5. Which device detects vehicles using changes in inductance caused
by a vehicle passing over a roadway loop?
A. Photocell
B. Inductive loop detector
, C. Radar reflector
D. Pedestrian push button
Answer: B. Inductive loop detector
Rationale: An inductive loop detector uses wire embedded in or
installed beneath the pavement. A vehicle's metallic mass changes the
loop's electromagnetic characteristics, allowing the detector unit to
identify vehicle presence.
6. What is a common function of a pedestrian push button?
A. It changes the traffic signal to flashing operation permanently
B. It requests a pedestrian crossing phase
C. It measures vehicle speed
D. It controls streetlight voltage
Answer: B. It requests a pedestrian crossing phase
Rationale: Pedestrian push buttons allow pedestrians to place a
crossing call with the signal controller. The controller then
incorporates the pedestrian phase according to its programmed
timing and operational requirements.
7. Which signal indication generally permits a movement when
conditions are otherwise safe and lawful?
