1|Page
IMSA Traffic Signal Technician 2 2025 Update
COMPREHENSIVE FREQUENTLY TESTED QUESTIONS
and verified answers WITH RATIONALES|100%
accurate answers | already graded A+
In a TS2 cabinet, how many times can the MMU experience a "Port 1 Fail" in a 24
hour period before
the fault is latched? - (ANSWER)1
On a 2070 MMU monitor unit, how does the field tech program allowable
phases? - (ANSWER)Remove diode on program card for allowable phases
On an MMU, is it possible to tape the reset button to prevent the traffic signal
from going into flash? - (ANSWER)Yes, it by-passes the conflict feature and will
not flash
On a NEMA CMU program card, how does the signal tech program allowable
phases? - (ANSWER)Install copper jumpers and soldering them on the program
card
According to best maintenance practices, how often should CMU/MMU be
tested? - (ANSWER)Annually
The MMU indicates a RED-FAIL fault on phase 6. Why? - (ANSWER)The load
switch/switch pack produces no outputs.
,2|Page
The purpose of the controller CVM (Controller Voltage Monitor) output is to allow
the CMU/MMU to
monitor the - (ANSWER)Controller health
When a Technician is recertifying the CMU/MMU at an intersection, what should
the technician do to have the intersection exit flash? - (ANSWER)Replace the
CMU/MMU with a newly tested unit
Absence of all colors on a load switch will be indicated by what fault on an MMU
or MMU2? - (ANSWER)Red Fail
Which of the following can be programmed on an MMU to latch after a fault
occurs? - (ANSWER)Field check
How often is an MMU's clock updated from the controller? - (ANSWER)Once a
second
In a signal cabinet, on the signal monitor, what does a field check indicate? -
(ANSWER)The signal indications don't match the controller output for a phase
A NEMA CMU/MMU uses a program card to tell the monitor which phases are
permitted to run together. Which answer is CORRECT? - (ANSWER)NEMA
monitors have wire jumpers missing in all positions, the tech solders the ones in
that allow phases to run together.
, 3|Page
When the controller timings DO NOT match the timing sheet, who should be
contacted for correct
times? - (ANSWER)Traffic Engineer
An older TS1 cabinet experiences a flash condition but the signal heads are also
showing active green, yellow, and red indications. What is the MOST COMMON
issue? - (ANSWER)The mercury contactor is stuck in the normal position.
In a Dual-Ring, 8-phase traffic signal controller, how many phases can run in each
ring at the same
time? - (ANSWER)1
Observations indicate that vehicles are being detected in one lane and that this is
shown on the detection interface unit. However, the controller does not show any
detection for that phase. This could be caused by - (ANSWER)Improper detection
phase assignment programming in the controller
As soon as vehicles leave the detection zone of an approach that has met its
minimum green time, a signal immediately goes to yellow from the green display.
This could be a result of - (ANSWER)no extension time programmed.
What is one reason the phase interval may change even though there is still
vehicle demand? - (ANSWER)maximum green time has been met
IMSA Traffic Signal Technician 2 2025 Update
COMPREHENSIVE FREQUENTLY TESTED QUESTIONS
and verified answers WITH RATIONALES|100%
accurate answers | already graded A+
In a TS2 cabinet, how many times can the MMU experience a "Port 1 Fail" in a 24
hour period before
the fault is latched? - (ANSWER)1
On a 2070 MMU monitor unit, how does the field tech program allowable
phases? - (ANSWER)Remove diode on program card for allowable phases
On an MMU, is it possible to tape the reset button to prevent the traffic signal
from going into flash? - (ANSWER)Yes, it by-passes the conflict feature and will
not flash
On a NEMA CMU program card, how does the signal tech program allowable
phases? - (ANSWER)Install copper jumpers and soldering them on the program
card
According to best maintenance practices, how often should CMU/MMU be
tested? - (ANSWER)Annually
The MMU indicates a RED-FAIL fault on phase 6. Why? - (ANSWER)The load
switch/switch pack produces no outputs.
,2|Page
The purpose of the controller CVM (Controller Voltage Monitor) output is to allow
the CMU/MMU to
monitor the - (ANSWER)Controller health
When a Technician is recertifying the CMU/MMU at an intersection, what should
the technician do to have the intersection exit flash? - (ANSWER)Replace the
CMU/MMU with a newly tested unit
Absence of all colors on a load switch will be indicated by what fault on an MMU
or MMU2? - (ANSWER)Red Fail
Which of the following can be programmed on an MMU to latch after a fault
occurs? - (ANSWER)Field check
How often is an MMU's clock updated from the controller? - (ANSWER)Once a
second
In a signal cabinet, on the signal monitor, what does a field check indicate? -
(ANSWER)The signal indications don't match the controller output for a phase
A NEMA CMU/MMU uses a program card to tell the monitor which phases are
permitted to run together. Which answer is CORRECT? - (ANSWER)NEMA
monitors have wire jumpers missing in all positions, the tech solders the ones in
that allow phases to run together.
, 3|Page
When the controller timings DO NOT match the timing sheet, who should be
contacted for correct
times? - (ANSWER)Traffic Engineer
An older TS1 cabinet experiences a flash condition but the signal heads are also
showing active green, yellow, and red indications. What is the MOST COMMON
issue? - (ANSWER)The mercury contactor is stuck in the normal position.
In a Dual-Ring, 8-phase traffic signal controller, how many phases can run in each
ring at the same
time? - (ANSWER)1
Observations indicate that vehicles are being detected in one lane and that this is
shown on the detection interface unit. However, the controller does not show any
detection for that phase. This could be caused by - (ANSWER)Improper detection
phase assignment programming in the controller
As soon as vehicles leave the detection zone of an approach that has met its
minimum green time, a signal immediately goes to yellow from the green display.
This could be a result of - (ANSWER)no extension time programmed.
What is one reason the phase interval may change even though there is still
vehicle demand? - (ANSWER)maximum green time has been met
