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IMSA Traffic Signal Technician 2 Questions and Answers, Exams of Advanced Education

Chamberlain College of NursingAdvanced Education

IMSA Traffic Signal Technician 2 Questions and Answers

Typology: Exams

2025/2026

Available from 09/06/2025

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IMSA Traffic Signal Technician 2
Questions and Answers
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.
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.
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
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IMSA Traffic Signal Technician 2

Questions and Answers

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. 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. 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 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 - ANSWER-the detection being set to locking detection Of the following, which answer MOST LIKELY would require a controller database be verified to be correct? - ANSWER-When a controller upgrade has been performed Which offset mode is the easiest way to view progression in a coordinated corridor? - ANSWER- Beginning of green Why is it important for a Signal Tech to verify that the phase concurrency is the same in the controller as it is in the MMU or ATC CMU? - ANSWER-The MMU/CMU will keep the cabinet in flash until MMU mirrors what is programmed in the controller NEMA Standard TS2-2003 requires all but which of these detector faults to be reported to the controller? - ANSWER-Erratic counts Observations indicate that a phase is extending to maximum green on every cycle despite no vehicles being present in the detection zone. This could be caused by - ANSWER-a damaged loop detector for that phase A Tech is troubleshooting a cabinet where the controller is reporting a cycle fail. What does that mean? - ANSWER-There is more time in the sum of the splits than the time programmed for the first cycle. An intersection goes into flash every morning at exactly the same time. Which of the following is the LEAST IMPORTANT piece of data that can be retrieved from the cabinet? - ANSWER-Controller Voltage

What equipment is NOT used in troubleshooting a video detection system? - ANSWER-lightmeter What happens when a vehicle parks in a detector zone at an intersection using non-intrusive detection? - ANSWER-The detection system learns to remove the effect of the parked vehicle. Two adjacent lanes each have loop detectors which are connected to one channel of detection. Observations indicate that vehicles are not being detected in one lane. This could be caused by - ANSWER-a damaged loop connected in parallel. Which of the following terms is used to describe when two loop fields interact with each other in an adverse way? - ANSWER-Cross-talking Adding turns to a loop - ANSWER-Increases the inductance Which detection systems typically cannot be used for pedestrian detection? - ANSWER-Loops What is the BEST way to determine if a loop wire's insulation has failed? - ANSWER-Visual Inspection When installing a ground rod it MUST BE installed so that the Technician can obtain an ohm reading of - ANSWER-25 ohm or less. Logic ground should be - ANSWER-Isolated from cabinet. What is one of the QUICKEST ways to determine if a piece of electrical equipment has been burnt by a short or high voltage? - ANSWER-there will be an odor that can be detected What is a MAJOR reason for an AC line filter being installed in a cabinet? - ANSWER-To limit damaging effects of transient noise and other interference For the Emergency Vehicle Pre-Emption system, what is the BEST way for the Tech to test the operation of the system? - ANSWER-Drive the corridor with a vehicle equipped with an EVP transmitter. What is the importance of track clearance time in a railroad preemption? - ANSWER-It provides the time for vehicles to exit the track area prior to the gates being lowered. What is the LAST set of steps a Technician should do after repairing any pedestrian problems? - ANSWER- Document repairs in log book and observe the traffic signal operating for several cycles. Ensure that the pedestrian and vehicle phases are operating per plan. After a Tech has made a modification to a traffic signal, which of the follow is the MOST IMPORTANT to complete? - ANSWER-Document in cabinet log book and on signal intersection schematic. While in the field, where would an Tech find information about work that has been performed at a traffic signal intersection? - ANSWER-The cabinet log book, located inside traffic signal cabinet. The cabinet has been modified and new detection is added. Where is the MOST appropriate place to note the additions? - ANSWER-Add details to the log book noting all the changes Which of the following documents should a technician check when performing controller troubleshooting? - ANSWER-Maintenance logs/intersection drawings/timing charts

What is the standard used to define how traffic signal controllers and networks communicate? - ANSWER-National Transportation Communications for Intelligent Transportation systems (ITS) protocol (NTCIP). The traffic management center notifies a field tech that the communications to maple st. And 1st street cuts in and out. The tech arrives at the intersection finding the modem is overheating and indicator lights are blank. After about twenty minutes of checking cables, the tech notices the modem is active again and cool to the touch. The TMC confirms communications are restored. The tech Checks the log book and finds this problem is a recuring issue. what should the tech do? - ANSWER-Replace the modem A managed network switch is being used in the cabinet. What is needed in the IP programming of the controller to get through the switch and to the TOC? - ANSWER-Gateway The pedestrian assembly (pedestrian 6) on the SW corner was damaged in a traffic accident and the tech cannot repair until the following day. What should the Tech do until they return to replace the pedestrian assembly? - ANSWER-Make wiring safe. Bag opposite signal display pedestrian phase (6). Document in cabinet log book and work order system. Notify supervisor that they need a pedestrian display assembly and to schedule the installation. After doing any repairs at a traffic signal which of the following is the MOST IMPORTANT to do before leaving the intersection? - ANSWER-Observe signal is operating per plans. Which of the following could cause signals at an intersection to repeatedly go into flash? - ANSWER-The MMU shows conflict on phases 2, 6, and 4 during the red interval on 2 and 6. The phase 4 field terminal is blackened and the terminal screw is loose A traffic signal head for phase 8 east bound amber is out; the load switch is blown. The Tech checks field terminals in the cabinet with a multimeter and verifies the wire is shorted. Which of the following options describes the MOST LIKELY cause of the shorted wire? - ANSWER-Signal cable has rubbed through to bare copper. A technician is at an intersection with a signal indication that is out. What is the FIRST step the technician should take? - ANSWER-check output voltage in field wiring. A pedestrian phase is not being serviced after the push button is activated. What is the FIRST thing the technician should do? - ANSWER-Verify input is received in the controller. The Tech receives a call for a damaged signal head. When arriving on the scene, what is the FIRST thing the technician does? - ANSWER-Observe the intersection. The technician arrives at an intersection where all the signals are out. What does the technician do FIRST? - ANSWER-check the line service to make sure there is main power. The technician arrives at an intersection that is dark. What type of meter does the technician use the check voltage? - ANSWER-Multimeter A technician received a call that a signal head was knocked down. The technician arrives on scene, repairs the problem, observes the intersection is functioning properly and completes his job duties.

Glancing at the cabinet wiring schematic, how can a technician know they are working in a NEMA TS-1 8 phase cabinet? - ANSWER-Controller is connected to cabinet wiring using 3-4 multiwire connectors. What is the BEST test instrument to assist the Tech for locating bad fiber optic splices or cut fiber optic cables in the field? - ANSWER-Optical Time Domain Reflectometer (OTDR) What testing device would a tech use to verify continuity of a detector home run cable? - ANSWER- Multimeter. What is a way to verify the UPS has been connected and is operating properly? - ANSWER-Turn off the main breaker at the electric service disconnect. During inspection of the UPS connected at the traffic signal, the tech notices one of four batteries has expanded and bubbled. What is the recommended response? - ANSWER-Test other batteries, and replace the expanded bubbled battery along with other failing batteries. Which of the following MUST be done after changing the UPS batteries? - ANSWER-Document initial battery voltages and work done in the traffic signal cabinet log book. What should you do if the signal indications do not function properly after replacing the faulty signals? - ANSWER-Review cabinet blueprints to verify the wiring method. In a NEMA TS1 cabinet, a loop detector provides a call or input to the controller by providing - ANSWER- 12 VDC to the controller on the input pin Which statement does NOT include a step to evaluate detection inputs to the controller? - ANSWER- Perform a "one-call" to check for any utilities located underground. An approach has four signal heads for the through lanes, three overhead and one on the corner. In a cabinet without load resistors, how many reds have to fail before the CMU/MMU in the cabinet puts the cabinet in flash? - ANSWER- 3 Which alternative below presents a correct action to inspect a pedestrian actuation? - ANSWER-Use multimeter to verify voltage and continuity of wiring connected to the push button. While visible solder bubbles are acceptable in soldering joints, we should re-solder if there is any soldering leaking through the jumper board. - ANSWER-False What should we do if we see an indicator light or display screen with an "incorrect program" message in the controller display? - ANSWER-Reprogram the phase in the MMU/CMU and the controller. When must the technician reprogram the detector processor? - ANSWER-When adding new equipment, such as cameras and loops.