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ISMA TRAFFIC SIGNAL TECHNICIAN
PRACTICE EXAM 3 Questions and
Answers LATEST UPDATE 2024 TOP
RATED A+
The traffic field technician is responsible for performing what types of maintenance on signals? - CORRECT ANSWER - Preventive and Emergency The single most important focus for the traffic signal field technician is? - CORRECT ANSWER - Safety Three main categories of safety a traffic signal technician is responsible for? - CORRECT ANSWER - Safety of motorist and pedestrians His or her own personal safety Safety of public and personal property Traffic signal field technicians perform several maintenance and repair functions above the ground and roadway typically using what two vehicles? - CORRECT ANSWER - Bucket Truck Aerial lift (platform truck) While using a bucket truck or aerial lift what implement provides proper protection for the user? - CORRECT ANSWER - Protective Harness What responsibilities (liability) does a Traffic signal technician have while involved in repair, testing or maintenance? - CORRECT ANSWER - Legal liability Dealing with the public It is imperative that the traffic signal field technician maintain comprehensive what of all the steps taken during repair and maintenance of traffic signals? - CORRECT ANSWER - Documentation
What two instances are documentation required for a traffic signal field technician? - CORRECT ANSWER
- Routine maintenance Emergency repair
What two improvements differentiated electronic controllers from electro-mechanical controllers? - CORRECT ANSWER - More dependable Added many more features What was the standardization that primarily established a pin configuration in the controller and defined a function for every pin? - CORRECT ANSWER - NEMA TS- 1 The NEMA TS- 1 has three connectors which where known as: - CORRECT ANSWER - A,B, and C connectors NEMA TS- 1 had how many connectors? - CORRECT ANSWER - Three The NEMA TS- 1 defined every pin for each connector as either what two connection types? - CORRECT ANSWER - Input or Output NEMA also allowed manufactures to add an additional feature on the fourth connector. What was this connector know as? - CORRECT ANSWER - D connector What was the D connector commonly used for? - CORRECT ANSWER - Communications Pre-emption Other special features What three agencies joined together to help develop the 170 controller? - CORRECT ANSWER - California DOT City of Los Angeles California New York State DOT What controller is an open-architecture based general purpose microcomputer for traffic control? - CORRECT ANSWER - Model 170 controller What two specifications does the model 170 controller require? - CORRECT ANSWER - A specific hardware architecture
A specific processor How is the Type 179 controller specification similar to the 170 specification?(2) - CORRECT ANSWER - Open architecture Allows for interchangeability of components What is the primary difference between the 179 and 170 controller - CORRECT ANSWER - Uses a different microprocessor Who developed the model 2070 controller? - CORRECT ANSWER - CALTRANS The 2070 was introduced to supersede which controller? - CORRECT ANSWER - The 170 controller Which controller is compatible regardless of the manufacturer? - CORRECT ANSWER - The 2070 controller The 2070 provides more functionality than the 170 because of what features?(3) - CORRECT ANSWER - Additional processing power Ability to program in higher level languages Multiple high speed communications ports Define the acronym NTCIP - CORRECT ANSWER - National Transportation Communications for Intelligent transportation systems Protocol What is a set of standards established by the consortium for controllers, cabinets and other ITS devices?
- CORRECT ANSWER - The NTCIP The National Transportation Communication for ITS protocol was developed to accommodate what two things? - CORRECT ANSWER - Needs of subsystems User Services
Bucket trucks may have a boom that is capable of rotating and extending which is called? - CORRECT ANSWER - Articulating boom What are some disadvantages of an aerial platform lift?(4) - CORRECT ANSWER - Only extends vertically Cannot reach as high as boom trucks Must be parked on flat ground Must be positioned directly below work area. The primary purpose of the traffic signal monitor unit is to act as? - CORRECT ANSWER - Guard against system malfunction If a malfunction is present the monitoring unit will automatically put the intersection into what mode? - CORRECT ANSWER - Flashing condition An intersection will remain in flash mode until the monitor unit is? - CORRECT ANSWER - Reset The CMU and MMU checks the controller for what two things? - CORRECT ANSWER - Proper power Timing functions What will cause the monitor (CMU) to transfer the intersection into flash mode?(3) - CORRECT ANSWER
- Loss of power to the controller The 24 volt DC voltage of the controller is lost Time it takes to change from one indication to another is incorrect What does each conflict monitor have that is unique for that particular intersection - CORRECT ANSWER
- Program card What are short lengths of conductors on the program card called? - CORRECT ANSWER - Jumpers On the program card jumpers are installed to tell the unit "what" are considered compatible?(2) - CORRECT ANSWER - Movements Channels For NEMA type controllers positions not having jumpers are considered as? - CORRECT ANSWER - Conflicts Program cards for type 170 controllers use a "what" as a jumper to wire the positions which are considered conflicts? - CORRECT ANSWER - Diode Why is it important to periodically review the monitor cards? - CORRECT ANSWER - To be sure the jumpers are assigned correctly What is used to provide the required flash rate when the signal is in flashing operation? - CORRECT ANSWER - Flasher unit The MUTCD requires that when a signal is flashed that the light source be flashed at a rate of? - CORRECT ANSWER - Not less than 50 or more than 60 times per minute
What relays are a type of relay that is capable of switching high levels of current? - CORRECT ANSWER - Mercury Contactor In a traffic signal cabinet the mercury contactor controls the 120 VAC to all of the? - CORRECT ANSWER - Load switches These devices are being replaced by many agencies due to what type of concerns? - CORRECT ANSWER - Environmental What are used in traffic signal controller cabinets that are solid-state devices that monitor a mechanical switch or button and report the call status back to the controller unit? - CORRECT ANSWER - Isolators What are the two basic types of isolator or isolator cards? - CORRECT ANSWER - AC isolators DC isolators What are the most common isolator cards? - CORRECT ANSWER - Loop detector cards What are two other special purpose cards? - CORRECT ANSWER - Video detector cards Emergency vehicle pre-emption Load switches in the controller cabinet receive 24V DC and switch (reroute) the 120V AC to the lamps in the signal head. This potentially reduces: (2) - CORRECT ANSWER - The number of faults induced into the controller from outside the cabinet. Electrical surges Why do some agencies operate signals in full operation mode for a period of time, then switch to flashing mode? - CORRECT ANSWER - To preserve the battery life Battery backup system manufactures claim that switching to red flashing operation at "what battery" level percent significantly extends run time? - CORRECT ANSWER - 40% What type of backup power systems require significant manpower and monitoring during use? - CORRECT ANSWER - Portable generator Intersections using LED displays use approximately what % of power that incandescent displays use? - CORRECT ANSWER - 10% What piece of test equipment can be directly connected to many different traffic signal control equipment groups? - CORRECT ANSWER - Laptop computer What are several of the functions a laptop computer can perform in relation to a traffic signal controller?(5) - CORRECT ANSWER - Set up equipment Download operational parameters to the equipment Upload signal system software Upload traffic signal timing plans Set up video detection
Tong tester Which test equipment works by reading the magnetic field around the conductor? - CORRECT ANSWER - Ammeter What is a unit that a signal technician uses to troubleshoot existing loops and test newly installed loops?
- CORRECT ANSWER - Loop Analyzer What does a loop analyzer measure?(5) - CORRECT ANSWER - Frequency Relative strength Impedance Change in inductance when vehicle is present Resistance Define TDR? - CORRECT ANSWER - Time domain reflectometer What is an electronic instrument used to characterize and locate faults in metallic cables? - CORRECT ANSWER - TDR - time domain reflectometer Because of the sensitivity to impedance variations, a TDR may be used to: (3) - CORRECT ANSWER - Verify cable impedance characteristics Splice and connector locations Estimate cable lengths What is a single sequence of displays that gives each movement at the intersection a chance to proceed through the intersection on a green indication? - CORRECT ANSWER - Cycle What is the total number of seconds between the start of a specific display until that display comes up again called? - CORRECT ANSWER - Cycle length In older electro-mechanical controllers the cycle is sometimes referred to as a? - CORRECT ANSWER - Dial Describes the direction of approach and the maneuver made at the intersection? - CORRECT ANSWER - (Vehicle) Movement Vehicle movements are usually recorded in a "what" that is typically included in the plans for a traffic signal? - CORRECT ANSWER - Timing chart How are vehicle phases typically numbered? - CORRECT ANSWER - 1 through 8 Which numbers in a vehicle phase a assigned to the through movements? - CORRECT ANSWER - Even numbers Which numbers are assigned to the left turn movements in a vehicle phase? - CORRECT ANSWER - Odd numbers
Which phases are typically assigned to the major-street through movements? - CORRECT ANSWER - 2 and 6 The through phases are numbered in which direction and start with which phase? - CORRECT ANSWER - Clockwise direction Phase 2 An intersection that has four through phases and four protected left-turn phases is said to be an "what" intersection? - CORRECT ANSWER - Eight-phase What is most commonly associated with a specific vehicular or pedestrian movement? - CORRECT ANSWER - Traffic signal phase What is the amount of time that a particular indication is given during a phase? - CORRECT ANSWER - Interval Each vehicular phase is usually comprised of three specific intervals: - CORRECT ANSWER - Green interval Yellow change interval Red clearance interval What is a series of conflicting phases that occur in an established order, but can never occur simultaneously with each other? - CORRECT ANSWER - Ring of a traffic signal controller Controllers typically have what two types of ring operation? - CORRECT ANSWER - Single Dual The number of rings is dependent upon "what" that is required for the intersection operation? - CORRECT ANSWER - Phasing When are controllers with 3 or 4 rings typically used? - CORRECT ANSWER - When two or more separate intersections are controlled by a single controller What are phases that cannot happen at the same time because they conflict with one another? - CORRECT ANSWER - Sequential phases In a sequential series of phases how many phases are served at a time? - CORRECT ANSWER - One What are used to provide signalization for specific movements that can be made while some of the other phases of the traffic signal cycle are being served? - CORRECT ANSWER - Overlaps Overlaps are different from other phases because they cannot be? - CORRECT ANSWER - Independently called into action There are two basic types of overlaps, known as what? - CORRECT ANSWER - Independent Parent/child
When establishing the minimum green time consideration must be given to(4): - CORRECT ANSWER - Pedestrian timing Density operations Controller type Detection design When there are no pedestrian features the minimum green time should be calculated by? - CORRECT ANSWER - At least equal the minimum time it would take a pedestrian to safely cross the intersection. Typically how many seconds for a left-turn phase? - CORRECT ANSWER - 3 to 7 How many seconds for a minor street through phase? - CORRECT ANSWER - 5 to 15 How many seconds for a major street through phase? - CORRECT ANSWER - 15 to 25 The minimum green time must be long enough to? - CORRECT ANSWER - Meet drivers expectations as to how long a green interval should be displayed. What is the period of time that the signal displays are red for all approaches? - CORRECT ANSWER - All- red clearance This interval allows for the intersection to "what" before a green phase starts again? - CORRECT ANSWER - Clear Factors used to determine the most appropriate time for an all red clearance include: - CORRECT ANSWER - Type of vehicular traffic Driver characteristics Pedestrian activity in the intersection What is the establishment of a definite timing relationship between adjacent traffic signals? - CORRECT ANSWER - Coordination timing Traffic signal coordination timings are developed to provide a degree of consistency that should allow traffic to? - CORRECT ANSWER - Progress through a number of intersections without stopping What within traffic controllers allow for timing plans to transition from one to another gradually so that traffic is not severely disrupted? - CORRECT ANSWER - Algorithms The amount of time that is allocated to a particular signal phase is the phases? - CORRECT ANSWER - Split A split includes what three things associated with the phase? - CORRECT ANSWER - Green time Yellow time Red time What is the transfer of the normal control of signals to a special signal control mode? - CORRECT ANSWER - Preemption timing
Preemption timing has the purpose of servicing? - CORRECT ANSWER - Railroad crossings Emergency vehicle passage Mass transit vehicle passage Other special tasks Preemption timing control requires "what" of normal traffic control to provide the priority needs of a special task? - CORRECT ANSWER - Terminating Transit preemption is often called what? - CORRECT ANSWER - Transit Priority Transit priority can operate by two different techniques: - CORRECT ANSWER - Green extension Red truncation What has the purpose of transferring the right of way to an emergency vehicle that needs to traverse an intersection? - CORRECT ANSWER - Emergency vehicle preemption What are the two types of emergency vehicle preemptions? - CORRECT ANSWER - Stationary Mobile How is stationary emergency vehicle preemption typically activated - CORRECT ANSWER - When an emergency responder depresses a pushbutton located within the facility. How does a mobile emergency preemption operate? - CORRECT ANSWER - Transmitter located in the emergency vehicle Receiver located at the intersections How is the preemption input activated typically? - CORRECT ANSWER - When the transmitter gets close enough to the receiver for the emitted signal to be detected by the receiver. The three stages of drawbridge preemption are? - CORRECT ANSWER - The clearance of the bridge opening area to permit the gates to be lowered. The omission of phases during the opening. The modification of phase timing after and, opening to clear standing queues. Preemption routines can be directly tied to the bridges via: - CORRECT ANSWER - Control circuitry Queue detectors, down stream from the intersection on the approach to the bridge. Railroad preemption should always be set to which level of priority? - CORRECT ANSWER - The highest Emergency vehicles should be set to which level of priority? - CORRECT ANSWER - Medium priority If multiple multiple preempts are set to the same priority, how are preempts served? - CORRECT ANSWER - On a first come first serve basis What are the two primary types of transit vehicle-preemption systems? - CORRECT ANSWER - Optical
Some advantages of video detection systems include: - CORRECT ANSWER - Can operate during roadway maintenance or construction Provides a quick way to move vehicle detection zones Can provide video images to a remote location Can be used for incident assessment Doesn't require cutting pavement What can Doppler microwave detectors detect? - CORRECT ANSWER - Volume Occupancy Classification Speed FMCW microwave detectors can detect "what" in addition to volume, occupancy, classification and speed? - CORRECT ANSWER - Vehicle presence What device is used for systems that use field master (closed loop systems) to control local intersections? - CORRECT ANSWER - Dial-up modem How do dial up modems function? - CORRECT ANSWER - Data transmitted to the dial-up line, then over telephone company's infrastructure back to the central computer Dial-up modems provide what in relation to the transition of data? - CORRECT ANSWER - Reliability Efficiency What does the use of fiber optic cables provide an agency? - CORRECT ANSWER - Much higher capability for transmission of data What are the two types of fiber optic cables commonly used? - CORRECT ANSWER - Single-mode Multi-mode What does POF stand for? - CORRECT ANSWER - Plastic optical fiber The fibers used in long distance telecommunications applications are always made of which material? - CORRECT ANSWER - Glass What is used to test the continuity of fiber optic cables? - CORRECT ANSWER - Fiber optic tracker Pocket visual fault locator What are the two general types of radios available for traffic control systems? - CORRECT ANSWER - Licensed or unlicensed The annual inventory should include what? - CORRECT ANSWER - Model and serial numbers of all equipment Date of installation
Photographic documentation If a component is determined to be repairable in the field, what is imperative that the field technician do? - CORRECT ANSWER - Clearly document every step taken in the repair What should field technician repair documentation include? - CORRECT ANSWER - Model and serial number Status of the replacement component What is the minimum required mode that the intersection should be placed in during repairs? - CORRECT ANSWER - Flashing mode If during a repair, flashing operation isn't available what step should be taken? - CORRECT ANSWER - Notify law enforcement to control traffic What are some benefits of traffic signal scheduled maintenance? - CORRECT ANSWER - Reduce the number of emergency repairs required Reduces delay to the motoring public Reduced travel times Reduced fuel consumption Reduce emissions into the atmosphere In simple terms what is a measurement of raw light? - CORRECT ANSWER - Lumens What is most significant advantage of using LEDs over incandescent lamps? - CORRECT ANSWER - Energy savings The IMSA traffic signal field technician certification is valid for how long? - CORRECT ANSWER - Three years If an equipment restoration effort requires replacement of equipment or specific items, disposition of the removed items should be recorded as: - CORRECT ANSWER - Sent for repair Not repairable/scrapped Scheduled for diagnosis What is usually the most efficient way to verify that the isolated component is the actual cause of the failure or malfunction? - CORRECT ANSWER - Testing What is the most important aspect concerning the testing equipment in relation to the field technician?
- CORRECT ANSWER - The technician is familiar with the operation of the equipment and its capabilities
