IMSA Traffic Signal Technician 2 Questions And
Answers | Latest Update 2026-2027 | Graded A+ |
100% Solved.
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
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
The MMU indicates a RED-FAIL fault on phase 6. Why? -
ANSWER-The load switch/switch pack produces no outputs.
The purpose of the controller CVM (Controller Voltage
Monitor) output is to allow the CMU/MMU to monitor the -
ANSWER-Controller health
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
,According to best maintenance practices, how often should
CMU/MMU be tested? - ANSWER-Annually
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
A NEMA CMU/MMU uses a program card to tell the monitor
which phases are permitted to run together. Which answer is
CORRECT? - ANSWERNEMA monitors have wire jumpers
missing in all positions, the tech solders the ones in that allow
phases to run together.
A signal tech is reviewing the controller logs and continually
sees a cycle fault error. What does that mean? - ANSWER-The
CU has not serviced a call in two cycles while in free mode.
A coordinated corridor is working well except at one intersection
where a platoon of vehicles is being stopped. The MOST
LIKELY problem is the - ANSWER-clock has drifted affecting
the offset and needs adjusting
Observations indicate that right turning vehicles approach the
intersection on the side street, stop and then make a right turn on
red. When this happens the signals cycle to the side street even
though there are no longer vehicles present in the detection
zone. This could be caused by - ANSWERthe detection being
set to locking detection
Answers | Latest Update 2026-2027 | Graded A+ |
100% Solved.
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
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
The MMU indicates a RED-FAIL fault on phase 6. Why? -
ANSWER-The load switch/switch pack produces no outputs.
The purpose of the controller CVM (Controller Voltage
Monitor) output is to allow the CMU/MMU to monitor the -
ANSWER-Controller health
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
,According to best maintenance practices, how often should
CMU/MMU be tested? - ANSWER-Annually
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
A NEMA CMU/MMU uses a program card to tell the monitor
which phases are permitted to run together. Which answer is
CORRECT? - ANSWERNEMA monitors have wire jumpers
missing in all positions, the tech solders the ones in that allow
phases to run together.
A signal tech is reviewing the controller logs and continually
sees a cycle fault error. What does that mean? - ANSWER-The
CU has not serviced a call in two cycles while in free mode.
A coordinated corridor is working well except at one intersection
where a platoon of vehicles is being stopped. The MOST
LIKELY problem is the - ANSWER-clock has drifted affecting
the offset and needs adjusting
Observations indicate that right turning vehicles approach the
intersection on the side street, stop and then make a right turn on
red. When this happens the signals cycle to the side street even
though there are no longer vehicles present in the detection
zone. This could be caused by - ANSWERthe detection being
set to locking detection
