FILENAME: H:\PROJFILE\11075 - INSYNC ADAPTIVE EVALUATION - HILLSBORO\REPORT\FINAL\CORNELL ROAD INSYNC
EVALUATION_DRAFT 3-19-12.DOCX
MEMORANDUM
Date: March 12, 2012 Project #: 11075
To: Galen McGill and Amy Mastraccio-Lopez
Oregon Department of Transportation
800 Airport Road SE
Salem, OR 97301
From: Eric Hathaway, P.E., Tom Urbanik, P.E., and Shing Tsoi, P.E.
Project: Transportation Operation Innovation & Demonstration Evaluation/Statewide
Subject: Cornell Road InSync System Evaluation
Executive Summary
The purpose of this technical memorandum is to present a comparison of operations between the
previously optimized time-of-day (TOD) operation signal timing plans and the InSync adaptive signal
system operation on Cornell Road in Hillsboro, Oregon. This memorandum pertains to the
Transportation Operation Innovation and Demonstration Evaluation/Statewide Work Order Contract
#28990, (Cornell Road Adaptive Signal System) and Washington County Project # 100103, and is
provided for your review and input. This memorandum presents a summary of the corridor
evaluation based on a travel time analysis performed using Bluetooth-enabled media access control
(MAC) address readers, as well as a performance measures evaluation at key locations along the
corridor.
Upon implementation of the InSync system, the traffic signals no longer operated using the
traditional concept of cycle lengths and coordination. Instead, InSync chooses a “state”, a pair of non-
conflicting phases, based on traffic demand and does not follow a set rotation of these states. In place
of offsets, the individual intersections communicate to create dynamic “green tunnels” with the
purpose of progressing vehicles from one end of the system to the other in platoons.”
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Figures 1 through 12 illustrate the evaluation results on the Cornell Road corridor from Brookwood
Parkway to Butler Street. During this project, this 1.7 mile stretch of road experienced main street
traffic volumes of approximately 1,500 to 2,000 vehicles per hour during the a.m. and p.m. peak
hours, respectively. Figures 1 through 3 summarize the travel time and delay results of this
evaluation and are provided in the body of this memorandum, while Figures 4 through 12 provide
additional detailed results and are provided in Appendix A. The evaluation team has observed the
following trends in comparing the adaptive system to the previous TOD operations:
Travel time improvement for weekday and weekend average daily periods, both eastbound
and westbound directions, though larger eastbound, possibly due to the location of the
sampling point which did not capture the delay due to holding vehicles for the eastbound
tunnel. Improvements ranging from 4 to 24 percent (9 to 54 seconds).
The InSync system appears to meter traffic at the entrance points to the corridor in order to
create platoons for the green tunnels and progress traffic better along the corridor.
TOD operations experienced very little delay at the video study intersections with no
intersection operating worse than 27 seconds of delay per vehicle. Average intersection delay
experienced little change (less than 5 seconds overall) at all video evaluation intersections
with InSync.
The InSync system generally increased period time (time between successive tunnels) by 15
to 20 seconds on average compared to cycles under TOD operations during the a.m. and p.m.
peak periods.
Based on the findings documented herein, the InSync adaptive signal system had an overall positive
effect on through traffic by improving through vehicle travel time on the corridor. The individual
intersections experienced small changes in overall delay with the InSync system, with more
degradations than improvements.
Introduction
The project evaluation corridor includes nine traffic signals and serves a variety of retail, residential
and office land uses to the north and south of the corridor. 231st Avenue provides access to the MAX
light rail line to the south. The Intel site north of Cornell Road is served by 229th Avenue, Shute Road
and Butler Avenue, while the Intel site to the south is served by Elam Young Parkway (East and
West). 48th Avenue serves Costco traffic to the north and Butler Street serves a large retail center to
the south. Orenco Station Parkway experiences higher pedestrian activity than the rest of the
corridor intersections. The project evaluation corridor was recently retimed in February of 2011,
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which provides a reasonable basis for comparison of the implemented adaptive signal system. Along
with the retiming effort, the existing 170 traffic signal controllers were replaced by 2070 controllers.
Ethernet communication was installed and flashing yellow arrows were added at some locations. The
TOD plans operated according to the schedule listed below:
Monday – Friday
6 – 11 AM – Coordination Plan 1
11 AM – 4 PM – Coordination Plan 2
4 PM – 7:30 PM – Coordination Plan 3
7:30 PM – 6 AM – Fully Actuated
Saturday – Sunday
9 AM – 7 PM – Coordination Plan 4
7 PM – 9 AM – Fully Actuated
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Corridor Modifications with InSync Implementation
Several changes to the Cornell Road corridor were made in order to implement the InSync adaptive
signal system, including modifications to the signalized intersection detection equipment, as well as
installation of InSync processors. The existing 2070 signal controllers in place before InSync was
installed were maintained, as were yellow and all-red timing setting from the TOD plans. The
maximum time between green tunnels was set at 130 seconds. Before installation of InSync, all
intersections along the evaluation corridor used loop detection, except for the 231st Avenue
intersection, which used video detection. Upon installation of InSync, the 2070 controllers running
Voyage software were set to free operations (i.e., controlled by InSync) throughout the day. Loop
detection was replaced with video detection zones of 150 to 250 feet on all intersection approaches.
A DSL subscriber line was installed for system access. These changes were made consistent with
InSync requirements to ensure that the system provided the necessary data for the InSync
algorithms.
InSync Strategies
The InSync adaptive signal system has a few unique operational characteristics that differentiate it
from a traditional signal system and other adaptive systems. Understanding the terminology and
strategy for the system is helpful in interpreting the analysis results in this report. InSync processors
are installed into the signal cabinet and interact with the existing controller using detector cards
plugged into the controller detector racks. The detector cards are specific to InSync and are
networked to the processor. The processor then places calls to the controller in the same manner as
an inductive loop does in a traditional setup.
The InSync system collects information via video detection at each intersection and reports it to a
“facilitator” intersection (231st Avenue). The facilitator makes decisions globally by creating “green
tunnels” where vehicles are intended to progress along the main line with minimal stops. This
sometimes requires that vehicles be metered at the entrance points to the system wait for the green
tunnel to start. The system also measures queues and percent occupancy at the intersection level to
decide how best to meet local demands. In place of phases, InSync assigns a “state”, which is a pair of
non-conflicting phases, based on traffic demand and does not follow a set rotation of these states. A
rotation of states between green bands is referred to as a “period.”
InSync is preprogrammed to meet typical changes in traffic conditions observed by the designing
engineers before installation of the system. During certain portions of the day, the system will
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operate with a specific set of operating parameters, which is called a “configuration”. For instance, on
Cornell Road, a configuration operated from 11 p.m. to 6 a.m. on weekdays with the green tunnel
algorithm disabled (adaptive uncoordinated), in order to allow for better side street operations
during this period where main street volumes are typically lower than other times of the day.
However, during the weekday p.m. peak period from 3:15 p.m. to 7:15 p.m., the system is attempting
to create green tunnels in both directions and has a set of green tunnel parameters that are different
from the midday and morning peak hour settings. Because InSync operates in real time states, it does
not cause phases to dwell during transitions between configurations, as happens with traditional
TOD operations. The list below summarizes the configurations and the corresponding period length
settings. InSync may begin a green tunnel early or late based on demand, so the observed period does
not always match the values identified below, however, the periods are generally consistent (within 5
seconds) of this value during a configuration. Exhibit 1 later in the report provides a sample of the
periods that occurred on a specific day during the study period.
Monday – Friday
6 - 7:15 AM – AM Peak 1 (105 Second Period)
7:15 – 10 AM – AM Peak 2 (115 Second Period)
10:00 – 11:15 AM - MID (105 Second Period)
11:15 – 12:45 PM – MID Peak (115 Second period)
12:45 – 3:15 PM – MID (105 Second Period)
3:15 – 7:15 PM – PM (130 Second Period)
7:15 – 11:00 PM – Off Peak (105 Second Period)
11 PM – 6 AM – Tunnel-less (Adaptive Uncoordinated)
Saturday – Sunday
6:30 AM – 7:15 PM – MID
7:15 – 11:00 PM – Off Peak
11:00 PM – 6:30 AM – Tunnel-less (Adaptive Uncoordinated)
Corridor Travel Time Evaluation
Travel time along the Cornell Road corridor was evaluated using Bluetooth-enabled MAC reader
technology before and after the InSync adaptive signal system implementation. The MAC readers
were placed at 48th Avenue and Butler Street to detect vehicles traveling along the corridor with a
time stamp to track their progress along the corridor. Table 1 summarizes the evaluation periods.
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Table 1 Cornell Road Travel Time Evaluation Periods
Periods Number of Days Exclusion Days
Before February 8, 2011 (Tuesday) to February 20, 2011 (Sunday) 13 February 14, 2011 (Monday)
After May 17, 2011 (Tuesday) to May 21, 2011 (Saturday) 5 None
Figures 13 through 14 below compare the TOD and InSync system travel times along 1.5 miles of
Cornell Road between the signalized Butler Street intersection at the east end of the project and the
48th Avenue intersection near the west end of the project for several time-of-day periods during
weekdays and weekends, respectively. These evaluation periods are referenced to the time-of-day
based coordination plan time periods prior to the implementation of the InSync adaptive signal
system. By organizing the travel time data in this way, it is possible to compare how the InSync
system operated to the TOD plans previously in place. These time periods are shown along the x-axis
in Figures 13 and 14 and were consistently applied for the TOD and InSync system conditions.
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Figure 13 Cornell Road Weekday Travel Time Before-and-After Comparison
Figure 14 Cornell Road Weekend Travel Time Before-and-After Comparison
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Table 2 Cornell Road Travel Time TOD Versus InSync Comparison
Pre-InSync Plan
Eastbound Westbound
Periods
Travel Time
Before (mm:ss)
Travel Time After
(mm:ss)
Travel Time ∆
(seconds)
Confidence Level for
Significant Change
Travel Time
Before (mm:ss)
Travel Time After
(mm:ss)
Travel Time ∆
(seconds)
Confidence Level for
Significant Change
Weekdays
Free 12:00 AM - 6:00 AM 2:40 2:34 -6 71% 2:34 2:54 21 89%
Coord 6:00 AM - 11:00 AM 3:09 2:57 -12 100% 3:29 3:10 -19 100%
Coord 11:00 AM - 4:00 PM 3:31 3:20 -11 100% 4:00 3:38 -22 100%
Coord 4:00 PM - 7:30 PM 3:57 3:08 -49 100% 3:48 3:45 -3 59%
Free 7:30 PM - 11:59 PM 3:28 2:52 -35 100% 3:12 2:59 -14 100%
24 Hour Average 3:30 3:06 -24 100% 3:42 3:26 -16 100%
Weekends
Free 12:00 AM - 9:00 AM 3:03 2:33 -29 100% 3:10 2:53 -17 98%
Coord 9:00 AM - 7:00 PM 3:54 2:57 -57 100% 3:34 3:28 -6 94%
Free 7:00 PM - 11:59 PM 3:20 2:43 -37 100% 3:04 3:16 12 90%
24 Hour Average 3:46 2:52 -54 100% 3:28 3:19 -9 100%
Bold indicates there is at least 95% confidence that average travel time change is significant
Table 3 Cornell Road Travel Time Reliability TOD Versus InSync Comparison
Pre-InSync Plan
Eastbound
Westbound
Periods Buffer
IndexBefore1
Buffer IndexAfter
1
∆ in Buffer Index
Buffer IndexBefore
1
Buffer IndexAfter
1
∆ in Buffer Index
Weekdays
Free 12:00 AM - 6:00 AM 35% 37% 2% 32% 52% 20%
Coord 6:00 AM - 11:00 AM 43% 50% 7% 38% 30% -8%
Coord 11:00 AM - 4:00 PM 41% 42% 1% 37% 36% -1%
Coord 4:00 PM - 7:30 PM 40% 41% 0% 34% 36% 2%
Free 7:30 PM - 11:59 PM 36% 34% -2% 39% 35% -4%
24 Hour Average 47% 44% -4% 39% 40% 1%
Weekends
Free 12:00 AM - 9:00 AM 46% 39% -6% 46% 36% -10%
Coord 9:00 AM - 7:00 PM 37% 32% -5% 34% 31% -2%
Free 7:00 PM - 11:59 PM 36% 46% 10% 34% 47% 13%
24 Hour Average 40% 37% -3% 36% 37% 1%
1 Buffer Index is the difference between the 95th percentile travel time and the average travel time, normalized by the average travel time.
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Figures 1 through 3 show that travel times along Cornell Road generally decreased with the InSync
adaptive signal system in place. Table 2 compares the change in travel time (seconds) between TOD
and InSync operations to the confidence level that the change is statistically significant. Confidence
levels are generally 95 percent or greater, due to large sample sizes and travel time changes of 10
seconds or more. Table 3 presents the change in buffer index between TOD and InSync conditions.
The buffer index is a measure of travel time reliability based on the 95th percentile travel time and the
average travel time. The buffer index is expressed as a percentage and “represents the extra time (or
time cushion) that travelers must add to their average travel time when planning a trip to ensure on-
time arrival.”1 For example, a motorist planning a trip that takes 20 minutes on average with a buffer
index of 20 percent should plan an additional four minutes for potential delay to ensure on-time
arrival 95 percent of the time. Therefore, a higher buffer index represents a less reliable travel
condition. A complete summary of travel time metrics for each time period is located in Appendix B.
PEAK PERIOD OPERATION
Observed travel time generally improved with the InSync adaptive system during the time periods
when traffic volumes were highest, i.e. between 6:00 a.m. and 7:30 p.m. on weekdays, and 9 a.m. and
7p.m. on weekends. Coordinated TOD plans were in operation during these time periods before
implementation of the InSync system. Savings were relatively consistent in both directions between
6 a.m. and 4 p.m. during weekdays, and were biased to eastbound between 4:00 p.m. and 7:30 p.m. on
weekdays and during weekend peak periods. A maximum saving of 57 seconds (24 percent) was
observed eastbound during the 9 a.m. to 7 p.m. weekend period. Travel time did not experience a
large change in the westbound direction from 4:00 p.m. and 7:30 p.m. during weekdays, nor between
9 a.m. and 7 p.m. during weekends. The decreases in travel time during these peak volume periods
are associated with only minor changes in the buffer index, typically around 0 to 5 percent (less than
10 seconds) with the exception of the 6 a.m. to 11 a.m. time periods, where the buffer index increases
by 7 percent (13 seconds) eastbound and reduces by 8 percent (17 seconds) on westbound Cornell
Road.
OFF-PEAK OPERATION
Travel time data shows that the InSync adaptive signal system generally has a positive effect on travel
times during lower volume periods in the early mornings and evenings as well. Under TOD
1 FHWA: Travel Time Reliability: Making it There on Time, All the Time.
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operations, the signals operated as fully actuated, or “free” during these lower volume periods.
Despite the lower volumes during these off-peak periods, travel time changes during weekday and
weekend early mornings and late evenings are comparable to changes during the peak periods.
Eastbound travel times improved more than westbound times during all off-peak periods and
resulted in overall corridor improvements, except during the weekday early morning period (12 a.m
to 6 a.m.) where overall travel time increased by 15 seconds. Buffer index values increased during
some lower volume time periods and decreased during others. The increases in buffer index were
higher than during the peak time periods and reached 20 percent (21 seconds) in the westbound
direction during the weekday early morning period.
A camera error was discovered after the study period that caused the system to operate in fog mode
at night. During this mode, the timing and phasing were based on historical data instead of the
current traffic conditions and no phases could be skipped, regardless of demand. The issue has been
addressed since the study was completed, so it is likely that current travel times, especially during
the off-peak periods, are different today than during the study period.
DAILY AVERAGES
Daily weekday and weekend averages show decreases in eastbound and westbound travel times,
with greater improvement in the eastbound direction. The larger eastbound improvements could be
influenced by the placement of the MAC readers. The MAC reader placed at Butler Street captured
delay of vehicles entering the corridor from the east; however, due to potential interference from the
high side street volumes, no reader was placed at Brookwood Parkway at the western end of the
system, Therefore, any metering of the system at Brookwood Parkway would not be captured with
the MAC readers. Average daily buffer index value changes are low in the eastbound and westbound
directions.
Intersection Analysis
Intersection level operations were analyzed to determine the effect of the InSync adaptive signal
system on intersection major and minor movements to complement the corridor-level travel time
analysis (MAC reader findings), and assess overall improvements or degradations to the
intersections, including impacts on minor side street movements and left-turning traffic.
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DATA COLLECTION
The following three intersections were chosen as representatives of the variety of traffic conditions
and signal operations along the corridor for analysis before and after implementation of the InSync
adaptive signal system. A brief description of each intersection is provided below:
Cornell Road and Brookwood Parkway – Four-legged intersection at the west end of the InSync
corridor serving east-west and north-south commuter traffic.
Cornell Road and Elam Young Parkway – Three-legged intersection serving the Intel campus
located south of Cornell Road.
Cornell Road and Orenco Station Parkway – Four-legged lower traffic volume intersection
serving retail land uses to the north and south. Serves a high number of pedestrians during
peak periods.
Video footage was collected at all approaches to the above intersections from 7 a.m. to 7 p.m. on the
following weekday dates:
Before conditions with TOD coordinated-actuated plans in place
Wednesday, February 9th, 2011
Thursday, February 10th, 2011
After conditions with InSync adaptive system operation
Wednesday, May 18th, 2011
Thursday, May 19th, 2011
Weekday a.m., midday off-peak, and p.m. peak video analysis periods were chosen based on 24-hour
tube counts (Appendix C) and loop counts provided by Washington County staff for conditions before
(TOD without advanced features) and after installation of the InSync system. The loop counts are
provided electronically under separate cover. The following peak and off-peak periods were chosen
to represent the varying traffic volume levels and patterns during a typical weekday. Weight was also
given to how closely the TOD and InSync traffic volumes correlated to diminish the effect of traffic
volume changes between the conditions.
AM peak hour = 7:45 - 8:45 a.m
PM peak hour = 3:15 - 4:15 p.m.
Midday off-peak period = 10:45 a.m. - 11:45 p.m.
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The number of vehicles at the evaluation intersections during the a.m., midday off-peak, period and
p.m. peak hour vary by a few hundred vehicles or less at lower volume intersections and by up to 700
vehicles per hour at the Brookwood Parkway intersection.
INTERSECTION MEASURES OF EFFECTIVENESS
Appendix D contains a list of all measures of effectiveness (MOEs) calculated at the video evaluation
intersections as well as the definition of each measure. Spreadsheets comparing each MOE for the
InSync and TOD conditions are found in Appendix E. Traffic operations were assessed at the three
video evaluation intersections to compare operations of the TOD plan to the InSync adaptive system.
Figures 1 through 12 (4-12 in Appendix A) summarize the change in operations at the intersection
level and along the corridor main line.
A normalization comparison was undertaken using Synchro to account for the impact of changes in
traffic volumes and patterns from the TOD analysis dates in February 2011 to the InSync adaptive
system analysis dates in May 2011. The volumes from both periods were entered into a Synchro
model provided by Washington County staff that was used to develop the TOD plans in place during
the video observations in February 2011. The change in delay between the February 2011 and May
2011 volume conditions, as calculated by Synchro, was used to estimate the delay changes that would
have occurred under TOD operations had the InSync system not been installed. The potential changes
due to volume only are provided in addition to the actual results, to give additional perspective to the
observed data. The normalization results show that traffic volume variations did not impact overall
intersection delay by more than 1-2 seconds at any location. Synchro worksheets are provided in
Appendix F.
WEEKDAY MORNING PEAK HOUR FINDINGS
Traffic volume levels at the video evaluation intersections remained fairly consistent during the a.m.
peak period, changing less than six percent before and after implementation of the InSync adaptive
signal system.
Before implementation of the InSync system, all traffic signals from Brookwood Parkway to Butler
Street were running on a coordinated system with a 100 second cycle length between 6 a.m. and
11 a.m. Upon implementation of the InSync system, the traffic signals no longer operated using the
traditional concept of cycle lengths and coordination. Instead, InSync choses a “state”, a pair of non-
conflicting phases, based on traffic demand and does not follow a set rotation of these states. In place
of offsets, the individual intersections communicate to create dynamic “green tunnels” with the
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purpose of progressing vehicles from one end of the system to the other in platoons. More
information on InSync operations can be found on the Rhythm Engineering website
(http://rhythmtraffic.com/index.php/insync/).
TOD Intersection Operations
As summarized in Figures 4 through 6 in Appendix A, the TOD video operations analysis shows that
the average vehicle (main and side street) at the Elam Young Parkway (West) and Orenco Station
Parkway intersections experienced 5-6 seconds of delay/vehicle, while vehicles at the Brookwood
Parkway intersection experienced 20 seconds of delay/vehicle. In terms of Highway Capacity
Manual2 standards for signalized intersections, this equates to level of service A at Elam Young
Parkway and Orenco Station Parkway, and level of service C at Brookwood Parkway.
Average delay for Cornell Road through traffic at the three video study intersections was quite low at
Brookwood Parkway (9-11 seconds/vehicle), and even lower at Elam Young Parkway (1-2
seconds/vehicle) and Orenco Station Parkway (2-3 seconds/vehicle). Average vehicle delay on side
street approaches were generally higher than main street approaches at all of the evaluation
intersections, and only one lane group (Cornell Road eastbound left-turn at Brookwood Parkway)
experienced more than 55 seconds of average delay/vehicle, which is the threshold between level of
service D and E operations according to the Highway Capacity Manual standards for signalized
intersections.
InSync Intersection Operations
A review of InSync operations shows only minor delay changes compared with TOD at the video
study intersections on both the main street and side street movements. Variations in delay would be
expected even if a new signal system were not installed, as traffic volumes and patterns changed
slightly between TOD and InSync operations along the corridor. No movements experience greater
than 55 seconds of delay per vehicle under InSync control, whereas one approach experienced
greater than 55 seconds of delay under TOD operations. Phase failures remain low at Orenco Station
Parkway and Elam Young Parkway, and decrease slightly at the Brookwood Parkway intersection (15
to 10). A phase failure is defined as when one or more queued vehicles are not able to depart an
intersection as a result of insufficient capacity during the cycle in which they arrive.
2 FHWA: 2010 Highway Capacity manual
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As shown in Table 4, the normalization of delay values for traffic volume changes between the TOD
and InSync conditions results in a change of 1 second or less. The adjusted delay increases average
dealy by 5 seconds or less at the study intersections. The increase in delay at the Brookwood
Parkway intersection appears to be related to the creation of eastbound “green tunnels”. Brookwood
Parkway is the westernmost intersection along the InSync corridor. The eastbound through
movement at this location consistently experiences approximately 10 seconds of additional delay per
vehicle during the a.m., p.m., and midday off-peak hours, which could reflect the InSync system
holding these vehicles to enable better progression along the rest of the corridor.
Table 4 A.M. Peak Hour Overall Intersection Delay – TOD Versus InSync
Intersection
TOD Plan Observed Delay
(Seconds Delay/Vehicle)
Delay Change Observed (Seconds
Delay/Vehicle)
Synchro Projected Delay Change (Seconds
Delay/Vehicle)
Normalized Delay Change (Seconds Delay/Vehicle)
Brookwood Parkway/Cornell Road 20 +4 -1 +5
Elam Young Parkway (West)/Cornell Road 6 +1 +1 0
Orenco Station Parkway/ Cornell Road 5 +2 0 +2
Corridor Travel Times
As shown in Figure 1, MAC readers reported travel time along Cornell Road between 48th Avenue and
Butler Street. The travel time was decreased with InSync by 12 seconds eastbound and 19 seconds
westbound (6-9 percent) during the morning peak period between 6 a.m. and 11 a.m., the period
when Coordination Plan 1 ran under TOD operations. This equates to an average savings of 1-2
seconds at each intersection along the InSync corridor.
Green Band Analysis
A review of the Synchro TOD Coordination Plan 1 (6 a.m. to 11 a.m.) 70th percentile traffic volume
band width diagrams (Figure 15) provide some insight into the progression improvements realized
under InSync operations. Band width diagrams illustrate the TOD implemented timing plans and
associated progression of vehicles along a corridor based on the phasing and offsets at the individual
intersections. The figure below shows that westbound vehicles would have a narrow window of 9
seconds where they could enter the corridor at Butler Street and progress through the entire corridor
without stopping, while eastbound vehicle progression provided a 30 second window. These
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illustrations represent how the system is designed to operate; however, individual driver behavior
and traffic variations will change the green windows occurring on the corridor.
The limited TOD westbound progression windows presented a potential for improved operations
(percent arriving on green) with the InSync system. Main street progression is a function of allocation
of green time at an individual intersection, and is also tied to how well the timing is coordinated
between signals to allow vehicles to arrive on green. Looking at the a.m. peak period TOD plans, the
three video study intersections at Brookwood Parkway, Elam Young Parkway (West), and Butler
Street were reasonably well situated in the eastbound progression, with vehicles arriving near or just
after the start of green on Cornell Road. Westbound, had relatively poor progression at Elam Young
and Brookwood Parkway (West). The progression diagram also shows that Cornell Road received a
majority of the green time under TOD operations at Elam Young (West) and Orenco Station, so if a
vehicle did not arrive on green, the delay for that vehicle awaiting the next green would be short.
Conversely, other intersections on the corridor had a large allocation of green time to the side street
(Butler Street, 231st Avenue, and Brookwood). Percent arrival on green eastbound (Figures 4, 5, and 6
in Appendix A) decreased significantly at Brookwood Parkway (likely due to the beginning of the
eastbound tunnel), and was largely unchanged at Elam Parkway (West) and Orenco Station Parkway.
Westbound TOD progression on the diagram is poor overall; however, percent arrival on green
observed in the video study only improved at Brookwood Parkway (likely due to holding eastbound
traffic for the eastbound tunnel) and was largely unchanged (slightly lower) at the other two
intersections.
WEEKDAY MIDDAY OFF-PEAK FINDINGS
Traffic volume levels at the video evaluation intersections (Brookwood Parkway, Elam Young
Parkway (West), Orenco Station Parkway) remained fairly consistent during the off-peak period,
changing less than 5 percent before and after implementation of the InSync adaptive signal system.
Before implementation of the InSync system, all traffic signals from Brookwood Parkway to Butler
Street were running on a coordinated system with a 110 second cycle length during the midday off-
peak hour. Upon implementation of the InSync system, the system no longer operated using the
traditional concept of cycle lengths and coordination as previously described.
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TOD Intersection Operations
As summarized in Figures 7 through 9 in Appendix A, the TOD video operations analysis shows that
the average vehicle (main and side street) at the Elam Young Parkway (West) and Orenco Station
Parkway intersections experienced 5-7 seconds of delay/vehicle, while vehicles at the Brookwood
Parkway intersection experienced 17 seconds of delay/vehicle. In terms of Highway Capacity Manual
standards for signalized intersections, this equates to level of service A at Elam Young Parkway and
Orenco Station Parkway and level of service B at Brookwood Parkway. Average delay for Cornell
Road through traffic at the three video study intersections was quite low at Brookwood Parkway (7-
10 seconds/vehicle) and even lower at Elam Young Parkway (3 seconds/vehicle) and Orenco Station
Parkway (2-4 seconds/vehicle). Average vehicle delay on side street approaches were generally
higher than main street approaches at all of the evaluation intersections and no lane groups
experienced more than 55 seconds of average delay/vehicle, which is the threshold between level of
service D and E operations according to the Highway Capacity Manual standards for signalized
intersections.
InSync Intersection Operations
A review of InSync operations shows only minor delay changes compared with TOD at the video
study intersections on both the main street and side street movements. As under TOD operations, no
movements experience greater than 55 seconds of delay per vehicle under InSync control. Phase
failures remained low at Orenco Station Parkway and Elam Young Parkway, however failures
increased from one under TOD operations to ten under InSync at the Brookwood Parkway
intersection, mostly on the eastbound and northbound approaches.
As shown in Table 5, the normalization for traffic volumes between the TOD and InSync conditions
results in average delay changes of 2 seconds or less for all vehicles entering the Elam Young
Parkway and Orenco Station Parkway intersections and 4 seconds at the Cornell Road/Brookwood
Parkway intersection. As under a.m. peak conditions, the small increase in delay at the Brookwood
Parkway intersection might be related to the creation of eastbound “green tunnels” as it is the
westernmost intersection along the InSync corridor. The eastbound through and left-turn movements
experience 10 seconds of additional delay per vehicle and six additional phase failures compared to
TOD operations during the midday off-peak hour, which could reflect the InSync system holding these
vehicles to enable better progression along the rest of the corridor.
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Table 5 Midday Off-Peak Overall Intersection Delay – TOD Versus InSync
Intersection
TOD Plan Observed Delay
(Seconds Delay/Vehicle)
Delay Change Observed (Seconds
Delay/Vehicle)
Synchro Projected Delay Change (Seconds
Delay/Vehicle)
Normalized Delay Change (Seconds Delay/Vehicle)
Brookwood Parkway/Cornell Road 17 +3 -1 +4
Elam Young Parkway (West)/Cornell Road 7 -2 -1 -1
Orenco Station Parkway/ Cornell Road 5 +2 0 +2
Corridor Travel Times
As shown in Figure 2, MAC readers reported travel time along Cornell Road between 48th Avenue and
Butler Street. The travel time was decreased with InSync by 22 seconds eastbound and 11 seconds
westbound (5-9 percent) during the midday off-peak period between 11 a.m. and 4 p.m., the period
when Coordination Plan 2 ran under TOD operations. Similar to the a.m. peak period, this equates to
an average savings of 1-2 seconds at each intersection along the InSync corridor.
Green Band Analysis
A review of the Synchro Coordination Plan 2 (11 a.m. to 4 p.m.) 70th percentile traffic volume band
width diagrams (Figure 16) provides some insight into the progression improvements realized under
InSync operations. Band width diagrams illustrate the designed progression of vehicles along a
corridor based on the phasing and offsets at the individual intersections. The figure below shows that
westbound vehicles would have essentially no progression (a window of 1 second) where they could
enter the corridor at Butler Street and progress through the entire corridor without stopping, while
eastbound vehicle progression provided a 23 second window. As previously mentioned, these
illustrations represent how the system is designed to operate; however, individual driver behavior
and traffic variations will change the green windows occurring on the corridor.
The non-existent TOD westbound progression presented a larger potential for improved operations
with the InSync system than during the a.m. period. Looking at the midday off-peak period TOD plans,
the three video study intersections at Brookwood Parkway, Elam Young Parkway (West) and Butler
Street were already well situated in the eastbound progression with vehicles arriving just after the
start of green on Cornell Road.
The diagram also shows that Cornell Road received a majority of the green time under TOD
operations at these locations, so even if a vehicle did not arrive on green, the delay for that vehicle
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awaiting the next green would be short. As shown in Figures 7, 8, and 9, Eastbound arrivals on green
are largely unchanged, except at Brookwood Parkway which is the beginning of the tunnel.
Westbound, percent arrivals on green increased slightly at Brookwood Parkway and Orenco Station
Parkway.
WEEKDAY AFTERNOON PEAK HOUR FINDINGS
Traffic volume levels at the video evaluation intersections remained fairly consistent during the p.m
peak period and changed by 3 percent or less at all locations before implementation of the InSync
adaptive signal system.
Before implementation of the InSync system, all traffic signals from Butler Street to Brookwood
Parkway were running on a coordinated system with a consistent 110 second cycle length. Upon
implementation of the InSync system, the system no longer operated using the traditional concept of
cycle lengths and coordination as previously described.
TOD Intersection Operations
As summarized in Figures 10 through 12 in Appendix A, the TOD video operations analysis shows that
the average vehicle (main and side street) at the Elam Young Parkway (West) and Orenco Station
Parkway intersections experienced 5-6 seconds of delay/vehicle, while vehicles at the Brookwood
Parkway intersection experienced 27 seconds of delay/vehicle. In terms of Highway Capacity Manual
standards for signalized intersections, this equates to level of service A at Elam Young Parkway and
Orenco Station Parkway and level of service C at Brookwood Parkway. Average delay for Cornell
Road through traffic at the three video study intersections was quite low at Brookwood Parkway (14-
17 seconds/vehicle) and even lower at Elam Young Parkway (1-2 seconds/vehicle) and Orenco
Station Parkway (4-5 seconds/vehicle). Average vehicle delay on side street approaches were
generally higher than main street approaches at all of the evaluation intersections and two lane
groups experienced more than 55 seconds of average delay/vehicle, which is the threshold between
level of service D and E operations according to the Highway Capacity Manual standards for
signalized intersections.
InSync Intersection Operations
A review of InSync operations shows only minor delay changes compared with TOD at the video
study intersections on both the main street and side street movements. Three movements experience
greater than 55 seconds of delay per vehicle under InSync control, compared to two under TOD
operations. Phase failures increased slightly at Orenco Station Parkway and Elam Young Parkway,
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however failures decreased from eleven under TOD operations to five under InSync at the
Brookwood Parkway intersection. Westbound left-turn movement phase failures decreased from five
under TOD operation to none under InSync operations. The reduced failures is likely a result of the
increased green time provided to this movement while the eastbound through movement was being
held before releasing vehicles in green tunnels through the corridor.
As shown in Table 6, the normalization for traffic volumes between the TOD and InSync conditions
results in average delay changes of 1 second or less for all vehicles entering the Brookwood Parkway
and Orenco Station Parkway intersections and 3 seconds at the Elam Young Parkway intersection.
Table 6 P.M. Peak Hour Overall Intersection Delay – TOD Versus InSync
Intersection
TOD Plan Observed Delay
(Seconds Delay/Vehicle)
Delay Change Observed (Seconds
Delay/Vehicle)
Synchro Projected Delay Change (Seconds
Delay/Vehicle)
Normalized Delay Change (Seconds Delay/Vehicle)
Brookwood Parkway/Cornell Road 27 0 +1 -1
Elam Young Parkway (West)/Cornell Road 5 +3 0 +3
Orenco Station Parkway/ Cornell Road 6 +3 +2 +1
Corridor Travel Times
The p.m. peak analysis period (3:15 p.m. to 4:15 p.m.) was chosen based on the traffic volume levels
under TOD and InSync operations. This period spans two TOD coordination plans, Coordination Plan
2 (11 a.m. to 4 p.m.) and Coordination Plan 3 (4:00 p.m. to 7:30 p.m.), with a majority of the video
analysis occurring during Coordination Plan 2. During the hours that Coordination Plan 2 operated
under the TOD scheme, the travel time was decreased with InSync by 22 seconds eastbound and 11
seconds (5-9 percent) westbound. As shown in Figure 3, during Coordination Plan 3, the travel time
was decreased with InSync by 49 seconds (21 percent) eastbound and 3 seconds (1 percent)
westbound. Accounting for the majority of the analysis period occurring during Coordination Plan 2,
this equates to an average savings of 2-3 seconds eastbound and 1-2 seconds westbound at each
intersection along the InSync corridor.
Green Band Analysis
The video analysis period (3:15 p.m. to 4:15 p.m.) spans two TOD coordination plans. A review of the
Synchro Coordination Plan 2 (11 a.m. to 4 p.m.) and Coordination Plan 3 (4:00 p.m. to 7:30 p.m.) 70th
percentile traffic volume band width diagrams (Figures 16 and 17) provides some insight into the
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progression improvements realized under InSync operations. Arterial bandwidth diagrams illustrate
the designed progression of vehicles along a corridor based on the phasing and offsets at the
individual intersections. The figures show that westbound vehicles would have essentially no
progression (a window of 0-1 second) where they could enter the corridor at Butler Street and
progress through the entire corridor without stopping, while eastbound vehicle progression provided
a 23-32 second window. As previously mentioned, these illustrations represent how the system is
designed to operate; however, individual driver behavior and traffic variations will change the green
windows occurring on the corridor.
The limited TOD westbound progression window present a large potential for improved operations
with the InSync system. Looking at the midday off- peak period TOD plans, the three video study
intersections at Brookwood Parkway, Elam Young Parkway (West), and Butler Street were
reasonably well situated in the eastbound progression with vehicles arriving after the start of green
on Cornell Road.
As in earlier time periods, eastbound percent arrival on green decreased at Brookwood (likely due to
beginning of tunnel). Eastbound percent arrival on green at Elam Parkway (West) was largely
unchanged and was improved at Orenco Station. Again, as in earlier time periods, westbound percent
arrival on green improved at Brookwood Parkway. However, westbound arrival on green decreased
significantly at Elam Parkway (West) and Orenco Station Parkway.
INTERSECTION CYCLE LENGTH EVALUATION
Cycle lengths under TOD operations were compared to the time between tunnels/green bands (time
for complete period until next tunnel) under InSync operations at Brookwood Parkway. While cycle
lengths for the TOD operation are documented here as reference, the purpose of this cycle time
evaluation is to study how InSync responds to volume fluctuations.
TOD Operation
The entire corridor between Brookwood Parkway and Butler Street was coordinated under TOD
operation. Table 7 summarizes the weekday cycle lengths used during the TOD operation.
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Table 7 Cornell Road Weekday Cycle Length Summary under TOD
Time Period (Weekdays Only) Cycle Length (sec) under TOD
12:00 AM - 6:00 AM Free
6:00 AM - 11:00 AM 100
11:00 AM - 4:00 PM 110
4:00 PM - 7:30 PM 120
7:30 PM - 11:59 PM Free
As shown, the corridor was running with fairly consistent cycle lengths throughout the day. The cycle
lengths range from 100 seconds to 120 seconds during weekday peak periods.
InSync Operation
As mentioned previously, InSync signals do not operate on a traditional order of phases. Instead,
InSync choses a “state”, a pair of non-conflicting phases, based on traffic demand. There is no set
rotation of these states. In place of offsets, the individual intersections communicate to create “green
tunnels” that progress vehicles from one end of the system to the other. Exhibit 1 summarizes the
time between green tunnels (period) under InSync operation on May 18. The periods reported below
were taken from the 15 minute averages reported by the Voyage logs provided by Washington
County. Tube counts on Cornell Road are also plotted on the same graphs to better illustrate the
period fluctuations with respect to traffic volume fluctuations.
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Exhibit 1 Cycle Time-Volume Plot for Cornell Road and Brookwood Parkway
Exhibit 1 shows that periods (time between green tunnels) under InSync operation generally did not
vary by more than 5 seconds within a configuration and followed the period setting for each
configuration, as identified below:
6 - 7:15 AM – AM Peak 1 (105 Second Period)
7:15 – 10 AM – AM Peak 2 (115 Second Period)
10:00 – 11:15 AM - MID (105 Second Period)
11:15 – 12:45 PM – MID Peak (115 Second period)
12:45 – 3:15 PM – MID (105 Second Period)
3:15 – 7:15 PM – PM (130 Second Period)
7:15 – 11:00 PM – Off Peak (105 Second Period)
11 PM – 6 AM – Tunnel-less (Adaptive Uncoordinated)
The periods ranged from approximately 100 seconds to 120 seconds during most of the morning and
early afternoon and increased up to the preset maximum of 130 seconds during the p.m. peak period.
The minor period length variation within a configuration appeared to generally react to variations in
traffic volumes smoothly with the prescribed constraints. The sharp increase in period time from 100
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seconds at 3 p.m. to approximately 125 seconds by 3:30 p.m is a result of the increase in traffic
volumes and the change in signal settings (period, global tunnel duration and offsets) from the “MID”
configuration to the “PM” configuration at 3:15 p.m. The gray shaded portions of the graph from 11
p.m, until 6 a.m. represent the “adaptive uncoordinated” configuration, during which the traffic
signals only optimize locally and do not attempt to create green bands.
INTERSECTION DATA COLLECTION
Before installation of the InSync adaptive system, traffic volume data was collected by induction
loops along Cornell Road and the side streets. After installation of InSync, traffic volumes were
recorded by the detection video cameras.
Traffic Volumes
As shown in Table 8, the absolute difference between the manual counts from the video recordings
and automatic counts (loop or video detection counts) range from 10 percent to 19 percent at most
intersections. At Orenco Station Parkway, the differences between manual counts and loop counts
were lower, in the range of 3 percent to 9 percent. In general, differences between loop counts and
manual counts were consistent, i.e. either positive or negative differences were observed across all
three time periods at each intersection. However, video detection counts may show a positive
difference from manual counts at one time period and negative difference at another time period at
the same intersection. Video detection counts and loop counts have similar degree of difference from
manual counts at Brookwood Parkway and Elam Young West. A more detailed breakdown of the
volume differences are provided in Appendix G. Not surprisingly, it is clear that the advanced loops
and video detection systems do not report traffic volumes uniformly, as they have different
configurations and methods by which they count traffic.
Table 8 Comparison of Intersection Total Entering Volumes between Manual and Loop Detection/Video Detection Counts
Intersection
TOD (2/10/2011) InSync (Video) (5/18/2011) InSync (Loop) (5/18/2011)
Manual Counts
Loop Counts
Difference |Loop -
Manual|* Percentage Difference
Manual Counts
Video Detection
Counts
Difference |Video -
Manual|* Percentage Difference
Manual Counts
Loop Counts
Difference |Loop -
Manual|* Percentage Difference
AM (7:45 - 8:45 AM)
Brookwood Parkway/
Cornell Road 3,187 3,266 485 15% 3,080 3,468 412 13% 3,080 2,762 442 14%
Elam Young West/ Cornell
Road 2,063 1,934 317 15% 2,183 2,245 408 19% 2,183 1,853 348 16%
Orenco Station/
Cornell Road 1,876 2,035 159 8% 1,855 2,105 250 13% 1,674** 1,577** 97 6%
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Intersection
TOD (2/10/2011) InSync (Video) (5/18/2011) InSync (Loop) (5/18/2011)
Manual Counts
Loop Counts
Difference |Loop -
Manual|* Percentage Difference
Manual Counts
Video Detection
Counts
Difference |Video -
Manual|* Percentage Difference
Manual Counts
Loop Counts
Difference |Loop -
Manual|* Percentage Difference
Off Peak (10:45 - 11:45 AM)
Brookwood Parkway/
Cornell Road 2,758 2,867 355 13% 2,730 2,629 419 15% 2,730 2,532 392 14%
Elam Young West/ Cornell
Road 2,130 1,948 312 15% 2,118 1,922 222 10% 2,118 1,900 218 10%
Orenco Station/
Cornell Road 2,084 2,154 70 3% 1,977 2,049 196 10% 1,836** 1,708** 128 7%
PM (3:15 - 4:15 PM)
Brookwood Parkway/
Cornell Road 3,520 3,574 376 11% 3,530 3,192 398 11% 3,530 2,798 842 24%
Elam Young West/ Cornell
Road 2,350 2,242 274 12% 2,415 2,166 435 18% 2,415 2,042 373 15%
Orenco Station/
Cornell Road 2,263 2,382 119 5% 2,259 2,479 220 10% 2,080** 1,900** 180 9%
* Values shown under "Total Entering Volumes" are sum of differences in absolute terms on each approach. For example, during the AM peak hour under TOD operations at Brookwood Parkway, the eastbound approach has a negative difference of 203 vehicle counts, while other approaches have a total positive difference of 282 vehicle counts; difference under "Total Entering Volumes" would be the sum of 203 and 282 which is 485 vehicle counts.
** At Orenco Station, traffic volumes from loops during InSync deployment periods do not include side street traffic due to missing data.
Percent Arrival on Green
Voyage logs recording the percentage of main street vehicles arriving on green were collected before
and after implementation of the InSync system at all 10 intersections along the corridor, except for
Brookwood Parkway, where the TOD plans were not able to be retrieved. Table 9 summarizes the log
data for the three video study periods (7:45-8:45 a.m., 10:45-11:45 a.m., 3:15-4:15 p.m.). The table
shows that percent arrival in green was generally unchanged in the westbound direction and shows
improvements of 2 to 4 percent eastbound. As mentioned previously, the manual percent arrival on
green counts consistently showed that the percent arrival on green eastbound at Brookwood
Boulevard decreased by approximately 15 to 25 percent due to metering of vehicles entering the
corridor from the west. Therefore, it is likely that if the Brookwood Parkway data were incorporated,
the eastbound percent arrival on green would be lower. A more detailed chart is included in Appendix
H showing the percent arrival on green at all 10 intersections in the eastbound and westbound
directions for the three study periods. This more detailed chart clearly illustrates the metering effect
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at the eastern end of the corridor (Butler Avenue), where westbound vehicles entering the corridor
experienced decreases in percent arrival on green of between 11 and 26 percent.
Table 9 Average Improvement of Percent Arrival with InSync
AM Midday PM
EB % Arrival on Green Change
+4% +2% +3%
WB % Arrival on Green Change
0% 0% 0%
Appendix H also includes a comparison of the manual counts and Voyage log percent arrival on green
calculations at the video study intersections. At Orenco Station Parkway and Elam Young Parkway
(West), the trends of decreases or increases in arrival on green percentage were the same in both
data sets, except for the midday westbound approach at the Elam Young Parkway intersection. The
change in percent arrival on green documented by the manual counts and Voyage logs were within
10 percent in all but two instances. Based on these findings, the percent arrival on green documented
by Voyage provides generally consistent results with the manual observations.
Stakeholder Interview
The project team conducted an interview with Stacy Shetler, the Traffic Engineering Manager for
Washington County, Oregon. Stacy oversaw the installation of the InSync system on Cornell Road and
currently monitors operations of the system. The interview regarding his experiences with the InSync
system is summarized in Appendix I. Some of the major findings from the interview are summarized
below:
The cost for installation of InSync was about $48,000 per intersection, including licensing, the
pedestrian module and cabinet changeouts.
Routine maintenance hours are similar to a traditional signal system once the system is
configured.
InSync can be configured to send system alerts via e-mail or text messages.
Technician maintenance is not very different than under TOD, as InSync still uses a 2070
controller with Voyage software.
Rhythm Engineering customer service can be reached 24-hours a day.
The success of the InSync system is highly related to the quality of detection on the corridor
and skill of the fine tuner.
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The system is preset to operate with different timing settings called operates “Configurations”
based on time of day.
Summary and Conclusions
A comparison of updated TOD plan operations and InSync adaptive signal system operations on
Cornell Road in Hillsboro, Oregon, reveals differences in performance between the two systems. The
InSync adaptive signal system provided travel time savings in both directions on Cornell Road of up
to 57 seconds from 48th Avenue to Butler Street (1.5 miles) during the higher volume time periods on
weekdays and weekends. Overall corridor travel times improved during all off-peak periods except
for the early morning (12 a.m. to 6 a.m.), where westbound increases outweighed the eastbound
decreases. Camera errors that occurred during the study period night-time hours that have since
been corrected were likely a contributing factor to the less efficient nighttime off-peak operations.
Average daily vehicular travel time for weekdays and weekends are all reduced with implementation
of InSync. The video analysis shows metering of vehicles entering the corridor from the west that was
not accounted for in the corridor travel time observations. For this reason, it is likely that actual
eastbound improvements were 5 to 10 seconds lower than those provided in the report. Changes to
the buffer index between TOD operations and the InSync adaptive system were mixed between
improvements and degradations and were generally less than 10 percent. Some buffer index
increases of 10 - 20 percent were recorded during off-peak periods. The improved travel times come
at the expense of a small increase in overall delay.
An evaluation of main street and side street weekday a.m. peak and p.m. peak operations at three
intersections along the corridor shows that the InSync cycle times between tunnels (periods) were
generally 10 to 20 seconds longer than the cycle lengths observed during TOD operations along the
corridor. Weekday midday TOD cycle lengths and InSync period lengths were similar. The length of
periods under InSync operation was strongly correlated to the configurations settings, but did vary
by about five seconds within configurations based on traffic demand.
The Brookwood Parkway intersection experienced between 17-27 seconds of delay per vehicle under
TOD operation, while the Orenco Station Parkway and Elam Young Parkway intersections
experienced less than 7 seconds of delay per vehicle. With implementation of the InSync system
overall delay per vehicle changed by less than 5 seconds (normalized for volume changes) per vehicle
at Brookwood Parkway and less than 3 seconds at Orenco Station and Elam Young Parkway in all
cases. Increases in delay at the Brookwood Parkway intersection appear to be tied to metering of
traffic on the eastbound approach while preparing green tunnels for the system.
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Based on the above findings, the InSync adaptive signal system had an overall positive effect on the
Cornell Road through traffic by improving through vehicle travel time on the corridor without large
increases to side street or main line left-turn movements.