movie scripts 2010-01-03 by huanghengdong

VIEWS: 7 PAGES: 13

									MOST – Hands On Signal Timing (Isolated Intersections)                        Movie Scripts


Lesson 1

Segment    Audio     Video (sec)   Script
           (sec)

           28.75                   The video for lesson 1 shows two cases, an aerial
1                                  view of two intersections, side by side. The
                                   physical aspects of both intersections are the
                                   same. All timing data and the detection systems
                                   are the same. The detection zones are 6 feet
                                   wide and 22 feet long, and are located at the stop
                                   bar. Only the traffic flow conditions are
                                   different. The simulation clock reads 41.4
                                   seconds. The simulation will be running in slow
                                   motion, at 20 percent of real time.

2          11.00                   Queues form on the southbound approach. Two
                                   vehicles are in queue in the left window and five
                                   vehicles are in queue in the right window. The
                                   display is red for phase 4, the phase serving the
                                   southbound through movement.

3          17.5                    The signal control status display shows the
                                   following information.
                                           A call is active on phase 4, but the phase is not
                                            currently timing
                                           Phase 2 is timing in ring 1 and phase 6 is timing
                                            in ring 2
                                           Phase 2 has just gapped out
4          6.5                     We will now shift our attention to the left window
                                   where a queue of two vehicles has formed on the
                                   southbound through lane during red.

5          11.5                    The display changes to green and the two vehicles
                                   in the queue begin to move. The minimum green
                                   timer begins to time down.

6          13.5                    Shortly after the beginning of green a call is
                                   received on phase 2 (one of the conflicting
                                   phases), so the maximum green timer becomes
                                   active and begins to time down.




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MOST – Hands On Signal Timing (Isolated Intersections)                     Movie Scripts


Segment    Audio     Video (sec)   Script
           (sec)

7          [13.5]                  When the simulation clock reads 50.6 seconds,
                                   both vehicles have entered the intersection. The
                                   detection zone becomes empty, and the call is
                                   dropped on phase 4. The vehicle extension timer
                                   begins to time down when the call is dropped.

8          10.5                    When the simulation clock reads 52.6 seconds, the
                                   vehicle extension timer expires, and as a result,
                                   the phase gaps out.

                                   Yellow now displays for phase 4.
9          14.5                    We will now shift our attention to the right
                                   window. The southbound through lane has a
                                   queue of nine vehicles that formed during red.

                                   The phase 4 display has changed to green and the
                                   queue began to move. The minimum green timer
                                   starts at 5 seconds and is timing down.

10         10.0                    The minimum green timer expires when the
                                   simulation clock reads 56.4 seconds. The vehicle
                                   extension timer is now displayed, with a starting
                                   value of 2.5.

11         6.5                     Since there is a call on phase 6, the maximum
                                   green timer also begins to time down.

12         17.5                    The southbound queue continues to move along
                                   the approach and enter the intersection. The
                                   vehicle extension timer begins to time down when
                                   the call is dropped (when there are no vehicles in
                                   the detection zone) but the timer continues to be
                                   reset to 2.5 when the next vehicle enters the
                                   detection zone.

12-2                               The vehicle extension timer times down to 1.8 seconds
                                   and is reset again to 2.5 when the next vehicle enters
                                   the detection zone.
12-3                               But another process also continues, that is the
                                   maximum green timer. The maximum green timer
                                   started when a call was received on a conflicting
                                   phase. It started at 20 seconds and now is at 6
                                   seconds.


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MOST – Hands On Signal Timing (Isolated Intersections)                     Movie Scripts


Segment    Audio     Video (sec)   Script
           (sec)

12-4                               These parallel processes continue as the queue
                                   continues to be served. A vehicle enters the detection
                                   zone, the vehicle extension timer is reset. A vehicle
                                   leaves the detection zone and the vehicle extension
                                   timer begins to time down. All the while the
                                   maximum green timer continues to time down.
12-5                               While there are now five vehicles on the approach, the
                                   last vehicle in the original queue enters the detection
                                   zone and then the intersection. The maximum green
                                   timer is down to one second.
13         [11.0]                  The queue is still clearing when the maximum
                                   green timer expires when the simulation clock
                                   reads 71.4 seconds. The phase “maxes out.”

                                   Yellow is now displayed for phase 4.




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MOST – Hands On Signal Timing (Isolated Intersections)                   Movie Scripts


Lesson 2

Segment Audio        Video (sec)   Script
        (sec)
1       15.75        00.0          The video for lesson 2 shows two cases, aerial
                                   views of two intersections, side by side. The
                                   geometry of both intersections is the same. The
                                   detection zones are different, however. In the
                                   left window, the zone is 22 feet long while in the
                                   right window the zone is 66 feet long.

2          10.00     00.0          The simulation clock reads 47.6 seconds. Phases
                                   2 and 6, serving the eastbound and westbound
                                   traffic, have just gapped out and the signal
                                   display for these phases is yellow.

3          18.50     00.0          Our focus is on the southbound approach, phase
                                   4. The display for this phase is currently red.
                                   Four vehicles are stopped on the southbound
                                   approach and two vehicles are about to enter the
                                   queue. The Controller Status display shows a “N”
                                   for phase 4, indicating that phase 4 will time
                                   next, after phases 2 and 6 have terminated.

4          13.00     00.0          The Vehicle Extension times and the Minimum
                                   Green times for phase 4 have been set to zero for
                                   both cases. Since these timers have been set to
                                   zero, the length of the detection zone alone will
                                   determine the duration of the phase 4 green
                                   display.

5          6.5       02.3          The phase 4 display turns green. Since there is a
                                   call on phase 6, the maximum green timer begins
                                   to time.

6-1        17.25     06.0          On the left, the second vehicle in the queue
                                   leaves the detection zone before the third vehicle
                                   enters. The vehicle extension timer immediately
                                   expires, as its initial value was set to zero. Phase
                                   4 gaps out.

7-1        6.5                     On the right, with the 66 foot detector, there is
                                   still at least one vehicle in the zone and phase 4
                                   continues to time.
8-2                                But there is now a long enough gap between the
                                   vehicle in the zone and the next one that even

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MOST – Hands On Signal Timing (Isolated Intersections)                  Movie Scripts


Segment Audio        Video (sec)   Script
        (sec)
                                   with the longer zone, the call is dropped and the
                                   phase gaps out. Yellow, and then red, is
                                   displayed for phase 4.




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MOST – Hands On Signal Timing (Isolated Intersections)                   Movie Scripts


Lesson 3

Segment    Audio     Video (sec)    Script
           (sec)
1          15.25                    The video for lesson 3 shows two cases, aerial
                                    views of two intersections, side by side. The
                                    geometry of the intersections is the same. The
                                    detection zones in both cases are 22 feet long.
                                    The Vehicle Extension time is set to 2.2 seconds
                                    for both cases.

2          15.75                    Our focus is on the southbound approach, or
                                    phase 4. There is one major difference between
                                    the two cases for phase 4. In the window on the
                                    left, the Minimum Green time has been set to 5
                                    seconds, while in the window on the right, the
                                    Minimum Green time has been set to 10 seconds.

3          3.25                     There is one vehicle in the queue for each of the
                                    two cases.

4          7.50                     Green is displayed for phase 4. The call is
                                    dropped when the vehicle leaves the detection
                                    zone, and the vehicle extension timer times
                                    down.

5          8.50                     Phase 4 gaps out for case one five seconds after
                                    the beginning of green, while phase 4 gaps out for
                                    case 2 ten seconds after the beginning of green.

6          6.50                     Case 1 terminates first because the Minimum
                                    Green time is set to 5 seconds, compared to 10
                                    seconds for case 2.

7          12.00                    The longer Minimum Green time for case 2, when
                                    there is only one vehicle in the queue, results in
                                    wasted or unused green time for phase 4 and
                                    longer delays for vehicles served by phases 2 and
                                    6.
8                                   The southbound approach now has a queue of
                                    four vehicles. We consider only case 1 (the
                                    window on the left). All four vehicles begin to
                                    move within the five second Minimum Green
                                    time.

                                    The phase continues to time after the Minimum

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MOST – Hands On Signal Timing (Isolated Intersections)                  Movie Scripts


Segment   Audio      Video (sec)    Script
          (sec)
                                    Green timer expires. Why? The time that the
                                    detection zone is unoccupied never exceeds the
                                    Vehicle Extension time of 2.2 seconds.

                                    Finally, the green display for phase 4 ends when
                                    the Vehicle Extension timer expires and the phase
                                    gaps out.




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MOST – Hands On Signal Timing (Isolated Intersections)                   Movie Scripts


Lesson 4

Segment    Audio     Video (sec)    Script
           (sec)
1          21.5                     The video for lesson 4 shows an aerial view of one
                                    intersection. In this video, we will observe the
                                    headways between the vehicles in a departing
                                    queue on the southbound approach of the
                                    intersection served by phase 4.

                                    The detection zone length is 22 feet. The
                                    Minimum Green time has been set to 7 seconds.
                                    The Vehicle Extension time has been set to 5.0
                                    seconds.

2          10.0                     Our task is to observe the headways between
                                    vehicles in the departing queue. There are ten
                                    vehicles in the southbound queue and the signal
                                    display is red for phase 4.

3          16.5                     The start of green for phase 4 occurs when the
                                    simulation clock is at 67.5 seconds. The queue
                                    begins to move and the vehicles enter the
                                    intersection. Vehicle 1 reaches the stop bar at
                                    68.7, or 1.2 seconds after the beginning of green.

4          6.5                      Vehicle 2 reaches the stop bar at 71.1, or 2.4
                                    seconds after the previous vehicle.

5          6.5                      Vehicle 3 reaches the stop bar at 72.8, or 1.7
                                    seconds after the previous vehicle.

6          6.5                      Vehicle 4 reaches the stop bar at 74.7, or 1.9
                                    seconds after the previous vehicle.

7          6.5                      Vehicle 5 reaches the stop bar at 76.5, or 1.8
                                    seconds after the previous vehicle.

8          6.5                      Vehicle 6 reaches the stop bar at 78.3, or 1.8
                                    seconds after the previous vehicle.

9          6.5                      Vehicle 7 reaches the stop bar at 80.0, or 1.7
                                    seconds after the previous vehicle.




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MOST – Hands On Signal Timing (Isolated Intersections)                   Movie Scripts


10        6.5                       Vehicle 8 reaches the stop bar at 81.9, or 1.9
                                    seconds after the previous vehicle.

11        6.5                       Vehicle 9 reaches the stop bar at 83.3, or 1.4
                                    seconds after the previous vehicle.

12        7.0                       Vehicle 10 reaches the stop bar at 85.0, or 1.7
                                    seconds after the previous vehicle.

13        4.0                       The green terminates and the yellow begins at
                                    90.3.




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MOST – Hands On Signal Timing (Isolated Intersections)                  Movie Scripts



Lesson 5:

Simulation      Script
time
(ss.s)
00.0            This video shows an aerial view of an intersection. Our focus is on
                the SB approach, or phase 4.
                 The detection zone length is 22 feet and it is located at the stop
                   bar.
                 The Minimum Green time has been set to 7 seconds.
                 The Vehicle Extension time has been set to 5.0 seconds.
                 The animation shows the SB approach, with one lane of TH
                   traffic.
                 The signal heads show the signal display status.
                 The controller status display shows
                          o If the phase is timing or not
                          o If a call is active on that phase
                          o Which phase is timing for each ring
                          o The status of each relevant timer, including yellow, all
                             red, vehicle extension, minimum green, and maximum
                             green
66.0            The simulation is moved to t = 66.0.
                 There ten vehicles in the queue and the signal display is red for
                   phase 4 (the SB TH lane).




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MOST – Hands On Signal Timing (Isolated Intersections)                  Movie Scripts


67.5            The start of green for phase 4 is t = 67.5. The queue begins to move
                and the vehicles enter the intersection.
                 Vehicle 1 enters the detection zone at t = 14.0; the rear of the
                   vehicle exits the zone at t = 69.8.
                 Vehicle 2 enters the detection zone at t = 69.4; the rear of the
                   vehicle exits the zone at t = 71.6.
                 Vehicle 3 enters the detection zone at t = 71.9; the rear of the
                   vehicle exits the zone at t = 73.2.
                 Vehicle 4 enters the detection zone at t = 73.9; the rear of the
                   vehicle exits the zone at t = 75.0.
                 Vehicle 5 enters the detection zone at t = 75.9; the rear of the
                   vehicle exits the zone at t = 76.9.
                 Vehicle 6 enters the detection zone at t = 77.7; the rear of the
                   vehicle exits the zone at t = 78.6.
                 Vehicle 7 enters the detection zone at t = 79.4; the rear of the
                   vehicle exits the zone at t = 80.3.
                 Vehicle 8 enters the detection zone at t = 81.3; the rear of the
                   vehicle exits the zone at t = 82.3.
                 Vehicle 9 enters the detection zone at t = 82.7; the rear of the
                   vehicle exits the zone at t = 83.7.
                 Vehicle 10 enters the detection zone at t = 84.4; the rear of the
                   vehicle exits the zone at t = 85.4.
90.3            The green terminates and the yellow begins at t = 90.3.




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MOST – Hands On Signal Timing (Isolated Intersections)                  Movie Scripts



Lesson 6:
Design Exercise-Setting the Minimum Green Time and the Vehicle Extension Time
60 Minutes

Simulation      Script
time
(ss.s)
00.0            This video shows an aerial view of an intersection. Our focus is on
                the SB approach, or phase 4. We will observe the operation of
                phase 4 during four separate cycles.
                 The detection zone length is 22 feet and it is located at the stop
                   bar.
                 The Minimum Green time has been set to 10 seconds.
                 The Vehicle Extension time has been set to 5.0 seconds.
                 The animation shows the SB approach, with one lane of TH
                   traffic.
                 The signal heads show the signal display status.
                 The controller status display shows
                          o If the phase is timing or not
                          o If a call is active on that phase
                          o Which phase is timing for each ring
                          o The status of each relevant timer, including yellow, all
                              red, vehicle extension, minimum green, and maximum
                              green
51.0            The simulation is moved to t = 51.0 when the green is about to be
                displayed for phase 4.
                 There six vehicles in the queue and the signal display is red for
                   phase 4 (the SB TH lane).
                 The green begins at t = 51.1.
                 All six vehicles in the queue are served before the phase gaps
                   out.
                 Five of these six vehicles were discharged while the Minimum
                   Green timer was timing.
                 The phase extended for several seconds after the last vehicle
                   entered the intersection; the phase then gapped out.
                 The Vehicle Extension time was too long resulting in wasted
                   green time.
93.9            The next green for phase 4 begins at t = 93.9.
                 There is one vehicle in the queue at the beginning of green.
                 After this vehicle has discharged the green continues to time for
                   over 7 seconds, as the Minimum Green timer continues to time.
                 The Yellow begins at t = 103.9.
                 For this short queue, the Minimum Green time is too long.


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MOST – Hands On Signal Timing (Isolated Intersections)                    Movie Scripts


Simulation      Script
time
(ss.s)
147.1           The next green for phase 4 begins at t = 147.1.
                 There are six vehicles in the queue including two heavy vehicles.
                 The first two vehicles, including one of the heavy vehicles,
                   discharges during the Minimum Green time.
                 The fourth vehicle in the queue, also a heavy vehicle, is slow in
                   reaching the detection zone. The Vehicle Extension timer timed
                   for over 2.5 seconds before the fourth vehicle entered the
                   detection zone.
                 The call for vehicle 6 was dropped (vehicle 6 left the detection
                   zone) at t = 168.5.
                 The Yellow begins at t = 173.3.
                 The phase continued to time for a significant period after the
                   last vehicle exited the detection zone indicating that the Vehicle
                   Extension time is too long.
219.5           The next green for phase 4 begins at t = 219.5.
                 There are 10 vehicles in the queue at the beginning of green.
                 Each vehicle enters the intersection as the queue discharges.
                 While in some cases the Vehicle Extension timer begins to time
                   down, it never reaches zero before the next vehicle in the queue
                   enters the detection zone.
                 The call for the tenth vehicle is dropped (the vehicle leaves the
                   zone) at t = 239.7.
                 Before the Vehicle Extension timer expires, three more vehicles
                   arrive. The first of these three vehicles arrives in the zone at t =
                   243. The call for this vehicle is dropped at t = 245.5.
                 The second of these vehicles enters the zone at t = 247; the call
                   for this vehicle is dropped at t =248.3.
                 The third of these vehicles enters the zone at t = 250; the call is
                   dropped for this vehicle at t = 252.6.
                 Yellow begins at t = 254.6.




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