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IMSA TRAFFIC SIGNAL TECHNICIAN 2 EXAM 2026/2027 | Official
Practice Exam | TST2 Certification Prep | Pass Guaranteed - A+
Graded
Total Questions: 50 | Time: 90 min | Pass: 75%
TABLE OF CONTENTS
Section 1 | Electrical Principles & Safety | Q1 – Q10
Section 2 | Signal Controllers & Operations | Q11 – Q20
Section 3 | Detection Systems (Loop, Radar, Video) | Q21 – Q30
Section 4 | Conflict Monitoring & Malfunction Management | Q31 – Q40
Section 5 | National Electrical Code (NEC) & IMSA Standards | Q41 – Q50
Instructions: Choose the single best answer. Pass: 38 in 90 minutes.
══════════════════════════════════════
SECTION 1: ELECTRICAL PRINCIPLES & SAFETY Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 34-year-old technician named Marcus is troubleshooting a signal cabinet that
keeps tripping its 20-amp breaker. He measures the current draw on the load
side and reads 18.5 amps at steady state, but the breaker still trips after about
10 minutes of operation. The ambient temperature inside the cabinet is 115°F,
and the breaker is mounted in a crowded panel with poor ventilation.
A. The breaker is undersized and should be replaced with a 30-amp breaker.
B. The breaker is experiencing thermal overload due to elevated ambient
temperature and should be derated.
,2
C. The circuit has a ground fault that only appears under sustained load.
D. The wiring gauge is too small and needs to be upgraded to 10 AWG.
Correct Answer: B
Rationale: Thermal-magnetic breakers are sensitive to ambient temperature,
and NEC requires derating when ambient exceeds 104°F; at 115°F the breaker's
trip curve shifts downward, causing nuisance tripping below rated current. A
30-amp breaker (A) would violate NEC 310.16 and create a fire hazard if
conductors are sized for 20 amps. Ground faults (C) typically trip immediately,
not after a sustained period, and wire gauge (D) would show voltage drop or
heating rather than breaker trip at 18.5 amps.
Question 2 of 50
During a routine cabinet inspection, technician Sarah discovers that the neutral
conductor in a 208V three-phase service has been disconnected from the
terminal block and is contacting the cabinet frame. She measures 120V from
phase A to the cabinet ground and 120V from phase B to ground, but 208V
from phase C to ground.
A. This is normal for a delta-connected service with a high-leg.
B. The neutral has become energized and is creating a hazardous ground fault
condition.
C. Phase C has an open connection and is floating above ground potential.
D. The cabinet is properly grounded and no hazard exists.
Correct Answer: B
Rationale: When a neutral conductor contacts a grounded frame, it energizes
the entire cabinet at neutral potential and creates a shock hazard; the varying
phase-to-ground readings indicate an unbalanced neutral return path. A high-
,3
leg delta (A) would show 208V on the high leg consistently, not this pattern,
and an open phase (C) would show near-zero voltage to ground rather than
208V.
Question 3 of 50
Technician David is installing a new LED signal head and notices the
manufacturer specifies a power factor of 0.65. The existing incandescent load
on this circuit had a power factor of 0.95. The utility bills based on apparent
power (kVA), and David wants to minimize demand charges.
A. Add a capacitor bank in parallel with the LED load to improve power factor
toward unity.
B. Replace the LED driver with one rated at 0.95 power factor or higher.
C. Increase the circuit breaker size to handle the higher reactive current.
D. Install a step-up transformer to reduce the apparent power draw.
Correct Answer: B
Rationale: Specifying LED drivers with high power factor (≥0.90) is the most
reliable long-term solution and avoids the maintenance burden of external
capacitor banks that can fail or drift. While capacitors (A) can correct power
factor, they add components that degrade over time and may create
resonance issues; breaker sizing (C) does not address power factor, and
transformers (D) increase losses rather than reduce apparent power.
Question 4 of 50
A crew is replacing underground cable runs after a lightning strike damaged
the existing conductors. The foreman asks the apprentice to pull new 4 AWG
, 4
THWN-2 copper conductors through a 2-inch PVC conduit that already contains
six current-carrying conductors. The ambient soil temperature is 25°C.
A. The 4 AWG conductors are adequately sized for any signal cabinet load.
B. The conduit fill exceeds NEC limits and the conductors must be derated for
the number of current-carrying conductors.
C. THWN-2 insulation is not rated for direct burial and must be replaced.
D. The PVC conduit must be Schedule 80 for underground installations.
Correct Answer: B
Rationale: NEC 310.16 requires ampacity derating when more than three
current-carrying conductors are bundled in a raceway; with six conductors, the
ampacity must be reduced to 80% of the base value. Conduit fill percentage (A)
is a separate calculation from conductor derating, THWN-2 is explicitly rated
for wet locations and direct burial (C), and Schedule 40 PVC is permitted for
underground use where physical damage is not a concern (D).
Question 5 of 50
Technician Elena is called to a signalized intersection where the pedestrian
push buttons are delivering mild shocks to pedestrians during rain events. She
measures 45V AC between the push button housing and the nearby handrail.
A. The push button housing has an open ground connection and is
experiencing stray voltage from capacitive coupling.
B. The pedestrian signal transformer has a failed secondary winding.
C. The phase-to-neutral voltage in the area is abnormally high.
D. The handrail is improperly bonded to the signal ground system.
IMSA TRAFFIC SIGNAL TECHNICIAN 2 EXAM 2026/2027 | Official
Practice Exam | TST2 Certification Prep | Pass Guaranteed - A+
Graded
Total Questions: 50 | Time: 90 min | Pass: 75%
TABLE OF CONTENTS
Section 1 | Electrical Principles & Safety | Q1 – Q10
Section 2 | Signal Controllers & Operations | Q11 – Q20
Section 3 | Detection Systems (Loop, Radar, Video) | Q21 – Q30
Section 4 | Conflict Monitoring & Malfunction Management | Q31 – Q40
Section 5 | National Electrical Code (NEC) & IMSA Standards | Q41 – Q50
Instructions: Choose the single best answer. Pass: 38 in 90 minutes.
══════════════════════════════════════
SECTION 1: ELECTRICAL PRINCIPLES & SAFETY Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 34-year-old technician named Marcus is troubleshooting a signal cabinet that
keeps tripping its 20-amp breaker. He measures the current draw on the load
side and reads 18.5 amps at steady state, but the breaker still trips after about
10 minutes of operation. The ambient temperature inside the cabinet is 115°F,
and the breaker is mounted in a crowded panel with poor ventilation.
A. The breaker is undersized and should be replaced with a 30-amp breaker.
B. The breaker is experiencing thermal overload due to elevated ambient
temperature and should be derated.
,2
C. The circuit has a ground fault that only appears under sustained load.
D. The wiring gauge is too small and needs to be upgraded to 10 AWG.
Correct Answer: B
Rationale: Thermal-magnetic breakers are sensitive to ambient temperature,
and NEC requires derating when ambient exceeds 104°F; at 115°F the breaker's
trip curve shifts downward, causing nuisance tripping below rated current. A
30-amp breaker (A) would violate NEC 310.16 and create a fire hazard if
conductors are sized for 20 amps. Ground faults (C) typically trip immediately,
not after a sustained period, and wire gauge (D) would show voltage drop or
heating rather than breaker trip at 18.5 amps.
Question 2 of 50
During a routine cabinet inspection, technician Sarah discovers that the neutral
conductor in a 208V three-phase service has been disconnected from the
terminal block and is contacting the cabinet frame. She measures 120V from
phase A to the cabinet ground and 120V from phase B to ground, but 208V
from phase C to ground.
A. This is normal for a delta-connected service with a high-leg.
B. The neutral has become energized and is creating a hazardous ground fault
condition.
C. Phase C has an open connection and is floating above ground potential.
D. The cabinet is properly grounded and no hazard exists.
Correct Answer: B
Rationale: When a neutral conductor contacts a grounded frame, it energizes
the entire cabinet at neutral potential and creates a shock hazard; the varying
phase-to-ground readings indicate an unbalanced neutral return path. A high-
,3
leg delta (A) would show 208V on the high leg consistently, not this pattern,
and an open phase (C) would show near-zero voltage to ground rather than
208V.
Question 3 of 50
Technician David is installing a new LED signal head and notices the
manufacturer specifies a power factor of 0.65. The existing incandescent load
on this circuit had a power factor of 0.95. The utility bills based on apparent
power (kVA), and David wants to minimize demand charges.
A. Add a capacitor bank in parallel with the LED load to improve power factor
toward unity.
B. Replace the LED driver with one rated at 0.95 power factor or higher.
C. Increase the circuit breaker size to handle the higher reactive current.
D. Install a step-up transformer to reduce the apparent power draw.
Correct Answer: B
Rationale: Specifying LED drivers with high power factor (≥0.90) is the most
reliable long-term solution and avoids the maintenance burden of external
capacitor banks that can fail or drift. While capacitors (A) can correct power
factor, they add components that degrade over time and may create
resonance issues; breaker sizing (C) does not address power factor, and
transformers (D) increase losses rather than reduce apparent power.
Question 4 of 50
A crew is replacing underground cable runs after a lightning strike damaged
the existing conductors. The foreman asks the apprentice to pull new 4 AWG
, 4
THWN-2 copper conductors through a 2-inch PVC conduit that already contains
six current-carrying conductors. The ambient soil temperature is 25°C.
A. The 4 AWG conductors are adequately sized for any signal cabinet load.
B. The conduit fill exceeds NEC limits and the conductors must be derated for
the number of current-carrying conductors.
C. THWN-2 insulation is not rated for direct burial and must be replaced.
D. The PVC conduit must be Schedule 80 for underground installations.
Correct Answer: B
Rationale: NEC 310.16 requires ampacity derating when more than three
current-carrying conductors are bundled in a raceway; with six conductors, the
ampacity must be reduced to 80% of the base value. Conduit fill percentage (A)
is a separate calculation from conductor derating, THWN-2 is explicitly rated
for wet locations and direct burial (C), and Schedule 40 PVC is permitted for
underground use where physical damage is not a concern (D).
Question 5 of 50
Technician Elena is called to a signalized intersection where the pedestrian
push buttons are delivering mild shocks to pedestrians during rain events. She
measures 45V AC between the push button housing and the nearby handrail.
A. The push button housing has an open ground connection and is
experiencing stray voltage from capacitive coupling.
B. The pedestrian signal transformer has a failed secondary winding.
C. The phase-to-neutral voltage in the area is abnormally high.
D. The handrail is improperly bonded to the signal ground system.
