IMSA TRAFFIC SIGNAL EVALUATION TEST
QUESTIONS AND ANSWERS SURE A+
✔✔Signal interval -✔✔Time allocated to each color to remain illuminated before
transition to next phase
✔✔Cycle length -✔✔Total time taken for a complete sequence of signal indications
✔✔Cycle split -✔✔could be expressed as %, G + Y + R
✔✔Offset -✔✔Difference between defined point in coordinated green and system
referenced point
✔✔Timed overlap -✔✔Terminate after its controlling phase has terminated which may
operate as either lead or lag phase
✔✔Parent child overlap -✔✔Movement or traffic controlled by two or more phases
✔✔Catenary -✔✔curved shape a chain or rope assumes once it is hung and supported
from both ends - some agencies use it as an identifier for a particular span wire
✔✔Six types of cabinets & controllers -✔✔-Electrical Mechanical
• Pre-NEMA
• NEMA TS1 - Military style "A", "B", "C" and sometimes "D" connectors
• NEMA TS2 - 15 Pin Serial Connector port 1
• CALTRANS/170/179/2070 (controllers)
• ATC
✔✔Electromechanical Controller -✔✔The dials are equipped with keys that activate a
switch. (Not in use anymore)
, ✔✔Pre-NEMA -✔✔This was the age when the first solid state electronic devices came
into the public realm. Many manufacturers that were already doing electronic assembly
for all types of electronic equipment began making traffic signal controllers and
cabinets.
✔✔NEMA TS-1 -✔✔NEMA created standards in 1976, defined cabinet style and seven
sizes by number, controller functions in A, B, C harnesses, conflict monitor functions &
harnesses, load switches, flasher, and flash transfer relays, inductive loop detectors
✔✔NEMA TS-2 -✔✔More advanced standard, builds on NEMA TS1
✔✔Caltrans type 170, new york 179, 2070 -✔✔The robust and intelligent design of the
170/179/2070 cabinet series is perfect for any traffic control need. Meeting requirements
set forth by Caltrans, New York, and the FHWA,
these rugged cabinets offer easy access to interior assemblies.
✔✔Cabinet Type - ATCC & ATC -✔✔The Advanced Transportation Controller and the
Advanced Transportation Cabinet are the latest controller/cabinet standards designed to
provide an open architecture platform to support a wide variety of ITS applications,
while utilizing high-density / low voltage equipment.
✔✔Controller -✔✔Brain of system, receives inputs outputs, processes info, responsible
for timing signal phases, coordinating signal sequences, optimizing traffic flow
✔✔MMU/CMU -✔✔conflict monitor, monitors conditions of signals such as conflicting
signals, lack of signals etc. Monitors voltage in cabinet. Places in flash
✔✔How often should MMU/CMU be tested -✔✔Annually
✔✔Detection devices -✔✔• Loop amplifiers
• Magnetometers
• Video detection processors
• Radar detectors
• AC & DC isolators
• EVP or RR preemption detection
✔✔Power supply -✔✔Provides electrical power to traffic signal cabinet, includes
transformers, circuit breakers, power distribution equipment
✔✔BIU -✔✔Bus interface unit
✔✔Bus interface unit -✔✔Connects everything - signal controller, detectors, terminal
facilities, power, MMU, preemption
QUESTIONS AND ANSWERS SURE A+
✔✔Signal interval -✔✔Time allocated to each color to remain illuminated before
transition to next phase
✔✔Cycle length -✔✔Total time taken for a complete sequence of signal indications
✔✔Cycle split -✔✔could be expressed as %, G + Y + R
✔✔Offset -✔✔Difference between defined point in coordinated green and system
referenced point
✔✔Timed overlap -✔✔Terminate after its controlling phase has terminated which may
operate as either lead or lag phase
✔✔Parent child overlap -✔✔Movement or traffic controlled by two or more phases
✔✔Catenary -✔✔curved shape a chain or rope assumes once it is hung and supported
from both ends - some agencies use it as an identifier for a particular span wire
✔✔Six types of cabinets & controllers -✔✔-Electrical Mechanical
• Pre-NEMA
• NEMA TS1 - Military style "A", "B", "C" and sometimes "D" connectors
• NEMA TS2 - 15 Pin Serial Connector port 1
• CALTRANS/170/179/2070 (controllers)
• ATC
✔✔Electromechanical Controller -✔✔The dials are equipped with keys that activate a
switch. (Not in use anymore)
, ✔✔Pre-NEMA -✔✔This was the age when the first solid state electronic devices came
into the public realm. Many manufacturers that were already doing electronic assembly
for all types of electronic equipment began making traffic signal controllers and
cabinets.
✔✔NEMA TS-1 -✔✔NEMA created standards in 1976, defined cabinet style and seven
sizes by number, controller functions in A, B, C harnesses, conflict monitor functions &
harnesses, load switches, flasher, and flash transfer relays, inductive loop detectors
✔✔NEMA TS-2 -✔✔More advanced standard, builds on NEMA TS1
✔✔Caltrans type 170, new york 179, 2070 -✔✔The robust and intelligent design of the
170/179/2070 cabinet series is perfect for any traffic control need. Meeting requirements
set forth by Caltrans, New York, and the FHWA,
these rugged cabinets offer easy access to interior assemblies.
✔✔Cabinet Type - ATCC & ATC -✔✔The Advanced Transportation Controller and the
Advanced Transportation Cabinet are the latest controller/cabinet standards designed to
provide an open architecture platform to support a wide variety of ITS applications,
while utilizing high-density / low voltage equipment.
✔✔Controller -✔✔Brain of system, receives inputs outputs, processes info, responsible
for timing signal phases, coordinating signal sequences, optimizing traffic flow
✔✔MMU/CMU -✔✔conflict monitor, monitors conditions of signals such as conflicting
signals, lack of signals etc. Monitors voltage in cabinet. Places in flash
✔✔How often should MMU/CMU be tested -✔✔Annually
✔✔Detection devices -✔✔• Loop amplifiers
• Magnetometers
• Video detection processors
• Radar detectors
• AC & DC isolators
• EVP or RR preemption detection
✔✔Power supply -✔✔Provides electrical power to traffic signal cabinet, includes
transformers, circuit breakers, power distribution equipment
✔✔BIU -✔✔Bus interface unit
✔✔Bus interface unit -✔✔Connects everything - signal controller, detectors, terminal
facilities, power, MMU, preemption
