Traffic Signal Control Devices and Techniques, Exams of Advanced Education

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A traffic cycle / ( cycle length ) definition is? - Correct Answer- Is the total elapsed Time between the start of a specific display until the display comes up again. Example ( if the cycle starts at the beginning of a green display it will end when The same green display begins again after the red and yellow displays have been given. The acronym AWG stands for what? - Correct Answer- American wire gauge Americans with disabilities act of 1990 (ADA) is? - Correct Answer-Requirements ensuring equal opportunity for persons with disabilities and employment, state and local government services, Public accommodations, commercial facilities and transportation The acronym (CMS) stands for what? - Correct Answer- Changeable message sign

Changeable message sign is for what? - Correct Answer-Also known as variable message sign (VMS) and dynamic message sign (DMS) CMS are traffic control devices used for traffic warning, regulation, routing and management, and are designed to affect the behavior of motorist ( thus improve the flow of traffic) by providing real time highway related information What is a (Beacon)? - Correct Answer-A highway traffic signal with one or more signal sections that operates in a flashing mode. The acronym (ITS) stands for what? - Correct Answer- Intelligent transportation systems intelligent transportation systems (ITS) what does it do? - Correct Answer-Improves transportation safety and mobility and enhances productivity through the use of advanced information and communications technologies. ITS encompass a broad range wireless and wire line communications based information and electronics technologies (ITS) What is a (major street)? - Correct Answer-The street normally carrying the higher volume of vehicular traffic

The acronym (MMU)stands for? - Correct Answer- Malfunction Management Unit Malfunction management unit is? - Correct Answer-A device used to continually check for the presence of conflicting signal indications and other malfunctions and to provide an output response to conflict or malfunction. MMU is an advance type of conflict monitor that also communicates and monitors controller function. What is a minor street? - Correct Answer-That street normally carrying lower volume of vehicular traffic What is "offset" - Correct Answer-The time difference, or interval in seconds or percentage of cycle length between the start of the green indication of the coordinated phase and the system reference signal What is a "platoon" - Correct Answer-A group of vehicles or pedestrians traveling together as a group, either voluntarily or involuntarily, because of traffic signal controls ,geometrical or other factors

What is a "preemption control"? - Correct Answer-The transfer of normal operation of a traffic control signal to a special control mode of operation. What is a "Queue length "? - Correct Answer-Number of vehicles stopped or slowly moving in a line, where the movement of each vehicle is constrained by that of the lead vehicle What is a "signal warrant? - Correct Answer-A threshold condition that, if found to be satisfied as part of an engineering study, shall results in analysis of other traffic conditions or factors to determine whether a traffic control signal or other equipment is justified Which certification has level II and Level III? - Correct Answer- Traffic signal level II bench Traffic signal level II construction Traffic signal level II design Traffic signal level II field Traffic signal level III Bench Traffic signal level III Electrician (field)

(Traffic signal phase )is? - Correct Answer-Specific assigned timing function in the traffic signal controller. Are phases numbered 1 -8? True or false? - Correct Answer- True Even number phases are typically assigned to what movements? - Correct Answer-Through movements Phases 2-6 are assigned to? - Correct Answer-Major streets through movements Odd numbers ( 1,3,5,7) phases are assigned to what? - Correct Answer-Left turn phases An intersection that has four through phases and four left turn phases are considered how may phases together? - Correct Answer-Eight phase intersection Each phase is comprised of intervals? True or false? - Correct Answer-True

(Interval )is based on? - Correct Answer-The amount of TIME that a particular indication is given during a phase Another words, the total time assigned to a specific display. An example of an ( interval ) is? - Correct Answer-" the amount of time that a green indication is given during a particular phase. " (know as a "green _______ )" (Ring) in a traffic signal controller is? - Correct Answer-A Series of conflicting phases that occur in simultaneously( same time ) with each other What are the two typically ( ring ) that a traffic controller have ? - Correct Answer-"Single-ring" or "dual ring" What are other ( rings ) that are rarely used? And when are these types of rings used for? - Correct Answer-3 or 4 rings & (used for two or more separate intersections are controlled by a single controller)

What is a ( barrier)? - Correct Answer-Is a boundary point in the preferred sequence. Barrier that separates something so it won't have in the same time. How many (barriers) does a "dual ring controller" have? - Correct Answer-Two , one for leaving the MAJOR street and one for leaving the MINOR street. _______ ensure that green indications will not be given to conflicting movement at the intersection at the same time. - Correct Answer-Barriers What is a ( concurrent phase)? - Correct Answer-Are movements that happen at the same time because do not conflict ( collide) with one another. Example of a ( concurrent phase ) - Correct Answer-A Through movement and a adjacent left turn movement can move on the same time. What is a (sequential phase)? - Correct Answer-Cannot happen at the same time because they conflict with one another ( collide)

In a " sequential phases? How many movements can it have?

• Correct Answer-Only one phase is served at a time Traffic signal industry has developed basic standards that provide common terms snd concept , but the most important thing is to have an understanding of your_______ - Correct Answer-Local agency standards What is (traffic signal timing)? - Correct Answer-The assignment of specific number of seconds for each interval of each controller timing function. ________ are a more detailed assignment of specific portions of time within a phase. - Correct Answer-Phase intervals phase intervals can be? - Correct Answer-Green, yellow , red and pedestrian intervals A green interval is? - Correct Answer-Is the total time assigned to the green indication for a phase whether sequential or concurrent.

Minimum green or initial green time is? - Correct Answer-Is the absolute minimum time that the green indication must be displayed. How many basic time components or "sections of time " does a green interval have that equal the entire interval? - Correct Answer-Three basic time components Most agencies set a standard for a minimum green initial green time. For a left turn face. How long should that minimum green be displayed for? - Correct Answer-3 to 7 seconds Most agencies set a standard for a minimum green initial green time. For a minor street through phase. How long should that minimum green be displayed for? - Correct Answer-5 to 15 seconds Most agencies set a standard for a minimum green initial green time. For a major street through phase. How long should that minimum green be displayed for? - Correct Answer-15 to 25 seconds

The common meaning for a passage time/ extension time/ gap extension is? - Correct Answer-Is the amount of time when a conflicting call is present that the controller will continue to Display a green light after the last vehicle has been detected What is the concept of a "passage time" and "extension time"? - Correct Answer-Making the time long enough for a vehicle leaving the advance loop to get to a point where It will continue through the intersection if the light turns yellow "Gap extension" concept is? - Correct Answer-Making the time equal to the length of time between vehicles that is high enough so that the green time is no longer being used in thus it would be better to go to the next phase Maximum green time is? - Correct Answer-The highest amount of time that the green light can be displayed when a Conflicting call is present How is "maximum green times "for the various phases of the controller calculated? - Correct Answer-It's based on traffic volumes

The maximum times can vary during the different portions for a typical day, specially if the controller as part of an area wide coordinated traffic signal system.. is this passage true or false?

• Correct Answer-True Yello change interval does what? - Correct Answer-It alerts drivers that the green display has ended and that the right-of- way will be changing. The "yellow change interval" must give a sufficient time to allow......... what? - Correct Answer-Allowed drivers approaching the intersection either to come to a safe stop before reaching the stop line or to proceed into the intersection prior to the display of the rare indication. How is a " yellow change interval calculated? - Correct Answer-Typically based on the speed of approaching vehicles not the POSTED SPEED LIMIT! "Red Clearance Interval" provides what? - Correct Answer-A brief period of time between the end of the yellow display on one approach and the start of the green display on a conflicting approach

"Basically giving you time to drive to the other side of intersection. Red clearance interval provides a brief period of time. How much time does it give you? - Correct Answer-1 to 3seconds How is a red clearance interval calculated? - Correct Answer- The distance from the stop line to a point that is clear of conflicting vehicles and pedestrians A "pedestrian head "at a intersection gives the pedestrian what information? - Correct Answer-The time they need to safely cross the street Pedestrian timings include both ________ & _______________? - Correct Answer-Walk interval and Pedestrian change interval. What is a "walk interval"? - Correct Answer-The amount of time that is given to the pedestrian that is using the crosswalk to get to the other side of the crosswalk safely. ( it's not related to the time needed to cross the stree)

The MUTCD recommends _____ for the " walk interval " but allows the use of walk intervals as short of ______ seconds? - Correct Answer-7 seconds and 4 seconds During the " walk interval" , the " pedestrian signal head" displays what symbol? - Correct Answer-Steady walking person symbol during the walking interval. " pedestrian clearance time" should be sufficient to allow a pedestrian crossing in the crosswalk at the end of the WALKING PERSON symbol to travel at walking speed of? - Correct Answer-3.5 feet per second "Pedestrian clearance time" provides what? - Correct Answer- enough time for a pedestrian who just enter the crosswalk to reach a safe location at the other end of the crosswalk before a green indication is displayed for other traffic. A pedestrian change interval consisting steps are? - Correct Answer-1) UPRAISED HAND (symbolizing Don't Walk! ) signal indication shall begin immediately following the WALKING PEROSN (symbolizing walk) signal indication. Following the pedestrian change interval. Consisting of a (steady UPRAISED HAND) symbolizing don't walk signal indication shall be

displayed for at least 3 second prior to the release of any coming traffic. A " buffer interval consisting of a? - Correct Answer-Steady ( UPRAISED HAND ) symbolizing don't walk! The sum of the time of the _______ and _______ shall not be less than the calculated "pedestrian clearance time" - Correct Answer-Pedestrian change interval and the buffer interval "Buffer space " steady ( UPRAISED hand) shall? - Correct Answer-not begin later than the beginning of the red clearance interval if used. Minimum recall is? - Correct Answer-A set for a phase, the controller treat the phase as having a vehicle call whenever a red light is being displayed to that phase. What "recall" will cause the controller to display a green indication every chance it gets and to keep the green light on for at least the length of the time set as the ______ green time for the phase. - Correct Answer-Maximum recall

What "recall" will cause the controller to show a green light to the phase every chance it get, but only for the ______ green time unless there are detection inputs to the controller to extend the phase? - Correct Answer-Minimum recall "Maximum recall " is what? - Correct Answer-Is set for a phase, the controller treats the phase is having a vehicle call at all times "Pedestrian recall" is? - Correct Answer-Is set for a phase, the controller treat the phase as having a pedestrian call at all times. What "recall "will cause the controller to show a walk signal and pedestrian change interval to the phase every cycle. - Correct Answer-"Pedestrian recall" Traffic signal coordination timing is? - Correct Answer- Providing a efficient flow of traffic through multiple intersections, the reduction of stops and delays.

What are the basic terms that help "traffic signal coordination"? - Correct Answer-Cycle length , split , offset , yield point, force-off For coordination to happen, all of the coordinated traffic signals along the street must have the??? - Correct Answer- Same "cycle length" during the same time of the day The common cycle length at each intersection in the system can change throughout the day why? - Correct Answer-To handle different traffic Volumes, with higher cycle lengths Generally being used during peak hours and shorter cycle lengths being used during off-peak hours What "split " in traffic signal coronation timing? - Correct Answer-Is the number of seconds given to each phase at the intersection What is the "offset" of a cycle? - Correct Answer-The number of seconds from the common Signal cycle point, to another point.

What are some examples for a "offset point "? - Correct Answer-End of the green indication. End of mainline green, beginning of mainline green, first green The assessment of different_______ at the various intersections is what causes the intersection to work together.

• Correct Answer-"Offset" What is another point in the cycle of a coordinated traffic signal controller where the major street phase is allowed to end? - Correct Answer-Yield-point A "force-off" is? - Correct Answer-A command that forces the Traffic signal controller to end the green display. "Forcing something to change" The "traffic signal system" consist of what? - Correct Answer- Traffic signal controllers, detection systems, and computerized control usually from central system. Traffic signal controllers, detection systems, and computerized control are commonly called __________? - Correct Answer- Architecture meaning (format)

"Traffic signal system" allow agencies to coordinate traffic signal along what? - Correct Answer-A long roadways to monitor vehicular movements, to adjust traffic signal timing based on factors such as weather conditions or special events to manage incidents And even to perform maintenance Of some features of the system from a central location A closed loop system is? - Correct Answer-Is a distributed processor system with control logic provided at three levels The closed loop system is a distributed processor system with control logic provided at three levels. Those Three levels are: - Correct Answer-The local controller., the on-street master and the central computer. What are the disadvantages of a "closed loop system"? - Correct Answer-The inability to easily switch local controllers to a different on-street master in response to varying traffic conditions. What is a "central computer system "? - Correct Answer-a computer at a centralized location makes decisions and

communicates to each individual local controller in the system. The standard traffic signal controller receives commands from where and what happens if communication is lost? - Correct Answer-Receives commands from central computer, if communication is lost the local controller is forced to revert to its backup plan Communications in Closer loop system typically consist of what? - Correct Answer-A twisted repair copper cable or fiber optic cable between local controllers and on street masters and than either telephone modems back to the central computer or I some cases cable throughout the system. "Hardwire interconnect" is? - Correct Answer-The common term for a cable that transmits data between controllers and on street masters or between controllers and central computers Copper cables are terminated in local controller cabinets to an _______? - Correct Answer-"Interface panel"

Standard traffic signal controller receives commands from the? - Correct Answer-"Center computer system What is another option that can be used for transmitting and receiving signal system data? - Correct Answer-Telephone communications "Telephone system" is for what - Correct Answer-signal system communications "Leased telephone lines" are owned by who? And are assigned to who? - Correct Answer-Local telephone company and are permanently assigned to and used by the signal system after a contract is negotiated with the telephone company Closed loop systems often use a _________ communication method. - Correct Answer-"Telephone dial up" "Cell phones" are capable of what? - Correct Answer-A signal System communications and are a reliable medium in specific areas.

The use of "fiber optic cables " provide what? - Correct Answer-The agency with a much higher capacity for transmission of data What are the advantages of "radio or microwave communication"? - Correct Answer-Are the cost & they are less expensive to install & lower susceptibility to loss of communications. The disadvantage of "radio or microwave communication" is - Correct Answer-Difficultly of transmitting real time or once per second two way communications a "Time based coordination "is placed at? - Correct Answer- Independently set up In each controller. What is the advantage of "time base coordination"? - Correct Answer-Is the simplest system to install becuase a communications infrastructure is not need What is the disadvantage of "time-based communications"? - Correct Answer-Is that it is extremely unreliable and there are no status reports that can be obtained and a central location

What is a "time base coordination"? - Correct Answer-The least expensive method of coordinating a group of traffic signals. The "time based coordination" does not require what? - Correct Answer-Any communications between individual traffic signal controllers. The " flashing mode operation" can be either _______ , ______or _____? - Correct Answer-Planned ( late night flashing) scheduled (Flashing of a signal that is only needed at a certain times of the day or week ) or emergency (when the conflict monitor send the intersection into flashing) What are two types of "flashing mode operation " - Correct Answer-Yellow-red flash and red-red flash Where would you put a "red-red flashing mode" - Correct Answer-where there is a all way stop control. Where every approach has a stop sign. ( 4 way stop )

What are the methods for " preemption and priority "? - Correct Answer-Providing additional green time for specific movements that require special treatment beyond what the standard operation of the signal provides. Which item is for "higher importance"? - Correct Answer- Preemption Which item is for "lower importance"? - Correct Answer- Priority Where would you use a " yellow-red flashing mode"? - Correct Answer-The yellow in the major-street approaches and red flashing on minor streets What typical situations are defined as "preemption "? - Correct Answer-Railroad, drawbridge, and emergency vehicle

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What situations are defined as "priority "? - Correct Answer- Movement of buses,light rail, or trolleys in some urban scenarios

What are the differences between "preemption & "priority"? - Correct Answer-The difference is that "preemption "forces off a phase to provide a green indication for the preempted movement & "Priority "typically extends or calls green phase early to service the movement The "bench technician " is responsible for what? - Correct Answer-For testing and evaluating suspected faulty components using a wide variety of common And specialized pieces of test equipment to make a decision to repair , send to the manufacturer for repair , return to service or replace the item A "laptop computer" can be connected directly to traffic signal controllers and be used for what functions? - Correct Answer-

• uploading signal system software
• uploading traffic signal timing plans
• video detection set up What is a "multimeter"? - Correct Answer-Is a tool the will measure several different electrical & electronic properties

When would you use a "multimeter"? - Correct Answer-To check resistance, voltage, or current of a electrical circuit What is a "ammeter/current probe"? - Correct Answer-It is a device that measures the current flowing through a wire or Circuit. How does the "ammeter/current"probe work? - Correct Answer-It works by reading the magnetic field around the conductor. When do you use a "ammeter/ current probe"? - Correct Answer-To measure the amperes in Circuits in the controller cabinet "Milliamperes meters" are most commonly used to measure what? - Correct Answer-DC current and are capable of measuring AC current as well. What does a "megohmmeter " measure? - Correct Answer- The resistance or breakdown strength of conductor insulation