Certification Examination Practice

Illinois Traffic Signal Technician Certification Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a traffic signal controller?
• To store vehicle count data
• To assign right-of-way through timing and logic
• To record signal malfunctions
• To provide communications to the TMC

Rationale: Controllers organize signal phases and timing to safely assign

right-of-way.

• In Illinois, which manual provides the standard for traffic signal design

and installation? 1 / 4

• AASHTO Roadside Design Guide
• MUTCD (Manual on Uniform Traffic Control Devices)
• Illinois Highway Safety Manual
• ITE Trip Generation Manual

Rationale: The MUTCD governs all traffic control devices, including traffic

signals.

3. A ring-and-barrier diagram is used to show:

• Loop detector placement
• The sequence and compatibility of signal phases
• Communications routing
• Cabinet grounding layout

Rationale: Ring-and-barrier diagrams show how phases run concurrently

without conflict.

• What is the function of a conflict monitor (MMU)?
• Count vehicles in each phase
• Back up signal timing
• Detect and respond to conflicting signal indications
• Provide surge protection

Rationale: The MMU prevents unsafe conditions such as simultaneous

green for conflicting movements. 2 / 4

5. A flashing red indication requires drivers to:

• Proceed with caution
• Stop, then proceed when safe
• Yield only to pedestrians
• Stop and wait for green

Rationale: Flashing red is legally equivalent to a stop sign.

• Which component determines when vehicles are present at a signalized

intersection?

• Controller
• Detection system
• Load switch
• Flash transfer relay

Rationale: Detection systems identify vehicle presence and feed data to the

controller.

• Which type of loop cut is most commonly used for standard lanes?
• Chevron
• Triangle
• Rectangular
• Circular 3 / 4

Rationale: Rectangular loops are standard due to reliable detection

patterns.

8. The primary reason for grounding a traffic signal cabinet is to:

• Reduce communication noise
• Lower controller temperature
• Protect equipment and personnel from electrical faults
• Provide lightning data logging

Rationale: Grounding mitigates shock and equipment damage.

• A NEMA TS2 controller uses which communication protocol?
• Bluetooth
• Wi-Fi
• SDLC (Synchronous Data Link Control)
• Modbus

Rationale: TS2 components communicate via SDLC networking.

10. A preemption device is used primarily for:

• Special event timing
• Emergency vehicle priority
• Transit signal priority
• / 4