Programming and Replacing Equipment
Not publishedof exam
Traffic Signal Troubleshooting
Not publishedof exam
Traffic Signal Standards
Not publishedof exam
Operation, Phasing, Timing, Detection
Not publishedof exam
Installation and Testing
Not publishedof exam
Documentation and Asset Management
Not publishedof exam
Quick Facts
- Exam
- IMSA Field Technician II
- Body
- IMSA
- Prereq
- Level I plus two years
- Questions
- Not published
- Time
- Not published
- Pass
- Not published
- Weights
- Not published
- Program
- Two days
- Formats
- Hybrid, virtual, in-person
- Fee
- Set by host section
- Renewal
- 16 hours, three years
- Reinstate
- One year after expiration
- Registration
- Closes seven days before
- Standards
- MUTCD 11th Edition Revision 1
TS 2 Type 1 vs 2
Type 1
- All input output serial
- BIUs for every rack
Type 2
- Serial monitor and detection
- A, B, C connectors kept
Fully serial versus hybrid
Cabinet Equipment
- Controller unit
- Runs phase and timing
- Load switch
- Powers one signal channel
- Flasher unit
- Drives flashing mode output
- Flash transfer relay
- Bypasses controller during flash
- MMU
- TS 2 malfunction monitor
- CMU
- TS 1 conflict monitor
- BIU
- TS 2 serial interface
- SIU
- ATC cabinet serial interface
- Detector rack
- Holds detector amplifier cards
- Power supply
- Provides cabinet logic voltages
- Police panel
- Manual flash and advance
- UPS
- Runs signals during outage
BIU vs SIU
BIU
- NEMA TS 2 cabinets
- SDLC Port 1 bus
SIU
- ATC 5301 ITS cabinets
- Serial bus 1, 2
TS 2 versus ATC
Cabinet Standards
- NEMA TS 1
- Parallel A, B, C connectors
- NEMA TS 2 Type 1
- Fully serial SDLC cabinet
- NEMA TS 2 Type 2
- Serial monitor, parallel outputs
- SDLC Port 1
- 153,600 bps serial bus
- ATC 5301
- ITS cabinet standard
- Serial bus 1
- ATC cabinet SIU bus
Controller Programming
- Database backup
- Save before any change
- Phase sequence
- Order phases are served
- Channel assignment
- Load switch to indication
- Detector assignment
- Detector mapped to phase
- Coordination pattern
- Cycle, split, offset set
- Time-of-day schedule
- When each pattern runs
- Firmware version
- Record before and after
Flash Fault Order
Log, channels, load switch, field
Log: what trippedChannels: which conflictedLoad switch: test outputField: short or crossfeed
MMU vs CMU
MMU
- TS 2 cabinets
- Reports over Port 1
- Adds Port 1 timeout
CMU
- TS 1 cabinets
- Parallel wiring only
- No serial diagnostics
Serial monitor versus parallel
Flash Fault Picker
- All indications dark→Check service, breaker, power
- Intersection in flash→Read monitor fault display(Do not reset first)
- Fault reads conflict→Compare channels and load switches
- Fault reads red failure→Test load switch output
- Fault reads Port 1 timeout→Check SDLC cable, BIUs
- Flash after program change→Restore backup, verify channels
- Monitor trips again→Trace field short or crossfeed
Monitor Fault Types
- Conflict
- Conflicting greens detected together
- Red failure
- No active channel output
- Dual indication
- Two indications, one channel
- Clearance failure
- Yellow shorter than minimum
- Port 1 timeout
- SDLC communication lost
- CVM fault
- Controller voltage monitor dropped
- 24V monitor
- Cabinet logic voltage low
- Minimum flash
- Holds flash before restart
Electrical Theory
- Ohm's law
- V = I x R
- Power
- P = V x I
- Series circuit
- Same current, resistances add
- Parallel circuit
- Same voltage, currents add
- Voltage drop
- Current times conductor resistance
- Multimeter
- Reads volts, amps, ohms
- Clamp meter
- Current without breaking circuit
- Megohmmeter
- Tests insulation to ground
- Service disconnect
- Isolates cabinet from supply
Test Equipment
- Monitor tester
- Verifies fault detection response
- Loop analyzer
- Reads inductance and resistance
- Megohmmeter
- Finds insulation breakdown
- Ground tester
- Measures electrode resistance
- OTDR
- Locates fiber loss events
- Optical power meter
- Measures fiber end-to-end loss
- Laptop and software
- Uploads and backs up
Preventive Maintenance
- PM schedule
- Planned inspection intervals
- Cabinet cleaning
- Clear filters and debris
- Torque check
- Retighten terminals and hardware
- Ground test
- Verify electrode resistance
- Battery test
- Confirm UPS runtime, transfer
- Head inspection
- Check aim, seals, damage
- Monitor test
- Verify fault response periodically
MUTCD Verb Ladder
Shall, should, may, informational
Standard: shallGuidance: shouldOption: maySupport: informational
MUTCD Essentials
- Standard
- Mandatory statement, uses shall
- Guidance
- Recommended statement, uses should
- Option
- Permissive statement, uses may
- Support
- Informational, no requirement
- Part 4
- Highway traffic signals
- Part 8
- Railroad grade crossings
- Current edition
- 11th Edition, Revision 1
- Revision 1 date
- December 2025
- Section 4F.17
- Yellow and red clearance
- Section 4I.06
- Pedestrian intervals and phases
Pedestrian Walking Speeds
3.5 clearance, 3.0 walk plus clearance
3.5 ft/s: clearance interval3.0 ft/s: walk plus clearanceMeasure to far sideSlower speed where needed
Signal Indications
- Circular green
- Permissive, yield when turning
- Green arrow
- Protected exclusive movement
- Flashing yellow arrow
- Permissive left turn
- Steady yellow
- Right of way ending
- Red clearance
- All approaches show red
- Flashing red
- Stop, then proceed
- Flashing yellow
- Proceed with caution
Accessible Pedestrian Signals
- Locator tone
- Repeats at 1-second intervals
- Tone duration
- 0.15 seconds or less
- Tone audibility
- 6 to 12 feet
- Ambient response
- Tone tracks background sound
- Vibrotactile arrow
- On the pushbutton surface
- Arrow alignment
- Parallel to associated crosswalk
- Speech walk message
- Names the crossing street
- Walking speed
- 3.5 ft/s clearance interval
Preemption Priority Order
Train, boat, fire, police, rail, bus
Train: hardest to stopBoat: movable bridgeFire and EMS nextPolice, light rail, bus
Preemption vs Priority
Preemption
- Interrupts normal operation
- Trains and emergency vehicles
Priority
- Modifies normal operation
- Transit keeps normal sequence
Interrupt versus adjust
Detection Fault Picker
- Loop never calls→Megohmmeter test the lead-in
- Loop calls constantly→Inspect splice, adjust sensitivity
- Loop reading drifts→Check pavement cracks, sealant
- Video misses at night→Check lighting and aim
- Radar detects wrong lane→Re-aim, redraw detection zone
- Pushbutton gives no walk→Trace input to controller
Timing Intervals
- Minimum green
- Shortest green that serves
- Passage time
- Extension per detector actuation
- Maximum green
- Cap with conflicting call
- Yellow change
- 3 to 6 seconds
- Red clearance
- Not exceeding 6 seconds
- Walk
- Steady walking person interval
- Pedestrian clearance
- Flashing upraised hand interval
- Gap out
- Detector gap expired
- Max out
- Maximum green expired
- Force off
- Coordination terminates the phase
- Recall
- Call placed without detection
Maximum Preemption Time
Transfer + queue + separation
Transfer: reach track clearanceQueue: clear the tracksSeparation: clear before arrivalSum: maximum preemption time
Gap Out vs Max Out
Gap out
- Detector gap expired
- Demand satisfied early
Max out
- Maximum green expired
- Conflicting call still waiting
Demand ends versus timer
Timing Complaint Picker
- Side street waits long→Verify detection before timing
- Green ends too early→Review passage time setting
- Green never ends→Check maximum green, recall
- Platoon stops each signal→Review offset and cycle
- Walk time too short→Recalculate using 3.5 ft/s
- Signals lost coordination→Check time source, pattern
Coordination Terms
- Cycle length
- One complete phase sequence
- Split
- Time allotted per phase
- Offset
- Reference start time difference
- Yield point
- Coordinated phase may release
- Permissive period
- Window to serve phases
- Bandwidth
- Usable green through band
- Time-space diagram
- Progression plotted against distance
- Early return to green
- Coordinated phase starts early
Coordination Parameters
Cycle, Split, Offset
Cycle: full sequence lengthSplit: share per phaseOffset: reference start timeAll three must match
Offset vs Split
Offset
- Reference between signals
- Tunes corridor progression
Split
- Share within one cycle
- Splits sum to cycle
Between signals versus within
Detection Types
- Inductive loop
- Senses inductance change
- Detector amplifier
- Converts loop change to call
- Magnetometer
- Senses magnetic field change
- Magnetic detector
- Moving vehicles only
- Ultrasonic
- Sound waves sense presence
- Infrared
- Detects heat or reflection
- Radar
- Radio waves sense movement
- LIDAR
- Laser pulses measure distance
- Video
- Image processing detection zones
- Pedestrian pushbutton
- Places a pedestrian call
Presence vs Pulse Detection
Presence
- Call held while occupied
- Used at stop line
Pulse
- Momentary call output
- Used for counting
Held call versus momentary
Preemption and Priority
- Preemption
- Interrupts normal signal operation
- Priority
- Modifies normal signal operation
- Priority order
- Train outranks emergency vehicles
- Track clearance interval
- Clears queue off tracks
- Right-of-way transfer time
- Time before track clearance
- Queue clearance time
- Time to clear track
- Separation time
- Track clear before arrival
- Maximum preemption time
- Transfer, queue, separation combined
- Advance preemption
- Notice before warning devices activate
- Simultaneous preemption
- Signal and crossing notified together
- EVP
- Emergency vehicle preemption
- TSP
- Transit signal priority
IMSA Cable Numbers
19-1 signal, 50-2 lead-in, 51 loop
19-1: traffic signal cable20-1: traffic signal cable50-2: loop lead-in51-5 and 51-7: loop wire
Loop Wire vs Lead-In
Loop wire
- IMSA 51-5 or 51-7
- Sits in sawcut slot
Lead-in
- IMSA 50-2 cable
- Runs conduit to cabinet
Pavement versus conduit
Field Devices
- Mast arm
- Rigid arm on pole
- Span wire
- Signals hung on messenger
- Strain pole
- Anchors span wire tension
- Flashing beacon
- Warning or stop beacon
- Pedestrian hybrid beacon
- HAWK, dark until actuated
- RRFB
- Rectangular rapid flashing beacon
- Backplate
- Improves signal head contrast
- Pedestrian head
- Walk and clearance indications
- Signal head hardware
- Brackets, clamps, disconnect hangers
HAWK vs RRFB
Pedestrian hybrid beacon
- Dark until actuated
- Displays steady red indication
RRFB
- Flashing yellow only
- Never displays red indication
Stops traffic versus warns
Underground and Overhead Work
- Raceway
- Protected conductor pathway
- Pull box
- Access for pulling conductors
- Foundation
- Resists pole overturning loads
- Conduit fill
- 40 percent, over two conductors
- Splice
- Listed connector, insulation restored
- Termination
- Landed, torqued, labeled conductor
- Grounding
- NEC Article 250 rules
- Drip loop
- Prevents water tracking inside
- Pole plumb
- Verify after final torque
IMSA Cable Specs
- IMSA 19-1
- Traffic signal cable
- IMSA 20-1
- Traffic signal cable
- IMSA 50-2
- Loop detector lead-in
- IMSA 51-5
- Loop detector wire
- IMSA 51-7
- Loop detector wire
- IMSA 19-6
- Aerial or direct burial
Documentation Picker
- Before changing timing→Back up controller database
- After rewiring a cabinet→Redline the cabinet print
- Field differs from plan→Record as-built, notify agency
- Repair finished→Close work order, list parts
- Unsafe condition remains→Secure site, notify authority
Records and Assets
- As-built plan
- Field condition after construction
- Timing sheet
- Approved controller timing values
- Cabinet print
- Wiring and channel assignments
- Work order
- Authorized task and closeout
- Asset record
- Equipment, location, condition, history
- Database backup
- Restorable controller configuration
- Fault log
- Monitor and controller events
- Retention
- Supports agency liability defense
Plan Reading
- Phase diagram
- Movements assigned to phases
- Conductor schedule
- Wire counts per run
- Pole schedule
- Arm length and mounting
- Quantity sheet
- Pay items and counts
- Detail sheet
- Standard construction drawings
- Legend
- Symbol meanings on plans
Closeout Checks
- Functional test
- Verify every affected movement
- Flash test
- Confirm required flash indications
- Detection test
- Confirm calls reach controller
- Photo record
- Document final field condition
- Timing sheet update
- Match record to field
- Notification
- Inform agency and dispatch
Common Traps
Preemption vs priority
Preemption interrupts the sequence ≠ Priority only adjusts timing
MMU vs conflict monitor
MMU reports over Port 1 ≠ Conflict monitor has no bus
Offset vs split
Offset links adjacent signals ≠ Split divides one cycle
Gap out vs max out
Gap out means demand ended ≠ Max out means timer expired
HAWK vs RRFB
HAWK displays a red indication ≠ RRFB flashes yellow only
Loop wire vs lead-in
Loop wire sits in sawcut ≠ Lead-in runs through conduit
Detection vs timing fault
Check detection before retiming ≠ Bad detector mimics timing complaint
Dark vs flash
Dark means power is lost ≠ Flash is a controlled state
Yellow vs pedestrian intervals
Preempt cannot shorten yellow ≠ Preempt may shorten walk
Vehicle vs track clearance
Red clearance frees the intersection ≠ Track clearance empties the crossing
Last Minute
- 1.Prereq: Level I plus two years
- 2.Renewal: 16 hours every three years
- 3.Reinstate within one year of expiration
- 4.Yellow change: 3 to 6 seconds
- 5.Red clearance: 6 seconds maximum
- 6.Pedestrian clearance uses 3.5 ft/s
- 7.MMU = TS 2 monitor
- 8.CMU = TS 1 monitor
- 9.Preemption interrupts; priority only adjusts
- 10.Trains outrank emergency vehicle preemption
- 11.Gap out ends on demand
- 12.Max out ends on timer
- 13.Offset links signals; split divides cycle
- 14.IMSA 50-2 = loop lead-in
- 15.IMSA 19-1 = traffic signal cable
- 16.Back up database before programming
- 17.MUTCD: shall mandatory, should recommended
- 18.Fee is set by section
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