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Leveraging Existing Traffic Signal Infrastructure to Produce Performance Measures for System Optimization and Construction Acceptance. Advisory Committee. Study Advisory Committee Indiana LTAP Neal Carboneau and John Habermann Local Highway Departments and Engineering Firms
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Leveraging Existing Traffic Signal Infrastructure toProduce Performance Measures for System Optimization and Construction Acceptance
Advisory Committee • Study Advisory Committee • Indiana LTAP • Neal Carboneau and John Habermann • Local Highway Departments and Engineering Firms • Lafayette: Fred Koning • Elkhart County: Jay Grossman • BFS Engineering: Steve Hardesty • BFS Engineering: Tom Vandenberg • Vendors • Traffic Control Corp: Chip Lang • Purdue University Researchers • Principal Investigator: Darcy Bullock • Research Assistants: Ross Haseman and Chris Day
Background What are Traffic Signal Performance Measures? • Using the new generation of signal controllers to monitor and record actual traffic data • Analyzing the data to get a sense of how well the signal is performing, and plan changes • Analyzing the data later to verify that changes worked as planned
Why Do We Care? National Traffic Signal Report Card
Why Do We Care? BENEFITS OF EXCELLENCE IN TRAFFIC SIGNAL OPERATIONS If the nation supported its signals at an A grade level, quality of life and protection of the environment would benefit significantly, including: Reductions in traffic delay ranging from 15–40 percent; reductions in travel time up to 25 percent; and reductions in stops ranging from 10–40 percent. Reductions in fuel consumption of up to 10 percent. Reductions in harmful emissions (carbon monoxide, nitrogen oxides and volatile organic compounds) up to 22 percent. According to the Surface Transportation Policy Project, motor vehicles are the largest source of urban air pollution. Source: 2007 National Traffic Signal Report Card
Traffic Signal Timing Process Performance Measures Performance Measures
Current Practice Observe and Adjust Collect Model Deploy
Current Vendor Provided Performance Measures Not Enough for Real Optimization/Analysis Vendors will respond to specifications, but we need to know what to ask for
Issues • Data Collected is Expensive and Sparse • 6 AM to 6 PM one work day every three years • Analysis of Implemented Changes can be Subjective • ‘Watch’ traffic for 20 minutes • Phone calls from public
Performance Measure Evolution 2003 2006 Procurement Specification 2010 2008
Indiana LTAP Research Project • Adapt previous research to local agency level • Try performance measures with a wider array of equipment installations • Develop base number of recommended performance measures • Train agencies to implement tools
CR17 at Missouri • Test of performance measures at isolated LPA intersection. • Use of video detection with performance measures.
Sample Use of Performance Measures Purdue Progression Diagrams as Changes Were Implemented at CR17/Missouri
PCD Before Change,Phase 6, 02/17/09 Start of Yellow Triple Cycle End of Cycle End of Cycle Double Cycle N We want to shift platoon earlier Φ2 Φ3 Φ4 Φ1 Start of Green Φ5 Φ6 Φ7 Φ8 T
Predicted PCDAfter Change, Phase 602/17/09 Calc Offset 35s+19s=54s N We want to shift platoon earlier Φ2 Φ3 Φ4 Φ1 Φ5 Φ6 Φ7 Φ8 T
PCD After Change,Phase 6, 02/24/09 Time Change Was Implemented N Φ2 Φ3 Φ4 Φ1 Φ5 Φ6 Φ7 Φ8
PCDPhase 6, 02/25/09 54s offset ok with 60s cycle Subsequently Fixed on 3/09/09 N Φ2 Φ3 Φ4 Φ1 Φ5 Φ6 Φ7 Φ8 54s offset fails with 50s cycle
PCDPhase 6, 03/07/09 Not set back to TOD after correction, fixed 3/09 N Φ2 Φ3 Φ4 Φ1 Φ5 Φ6 Φ7 Φ8
PCDPhase 6, 03/20/09 N Φ2 Φ3 Φ4 Φ1 Φ5 Φ6 Φ7 Φ8
Future Work: CR17 Corridor • Apply performance measures to an LPA corridor • Follow after similar study on Indiana SR37
2010-2011: CR17 Corridor • 14 Signals • Links I-80/90 Toll Road with US20 and US33 • Volumes from 12,000 – 30,000 vpd • Letting this spring for communications interconnect project • Downloading of event logs from individual intersections to central database • Tools for performance measures work on downloaded database files
CR350 – Lafayette, IN Performance Measures as a Construction Acceptance Tool
Multiscale: Intersection Details Where are my Opportunities for improvement
Role of Performance Measures OurFocus
How do we know if the signal system is functioning as intended when we turn it on after construction? 9th St. 18th St. Regal Valley Osborne Concord
Data Collection • About 150,000 events occur every day at each intersection • Current generation controllers can record these events to 0.1 second fidelity for analysis 9th St. 18th St. Regal Valley Osborne Concord
Abbreviated Performance Measure Based Checklist • Are the detectors detecting? • Are the counts reasonable? • Are all of the phases active? • Are the TOD plans working correctly? • Are our green time allocations reasonable? • Is our progression functioning?
1. Are the detectors detecting? NA NB NL EA EAc EL ELc SA SL Sac SLc WA WB WAcWBc WL WLc Detectors 1, 2, 3, 4, 5, and 7 (NA, NB, and NL) not reporting detections, as their conduit was crushed during construction. (9th St.) Detectors 1, 2, 3, 4, 5, and 7 (NA, NB, and NL) not reporting detections, as their conduit was crushed during construction. (9th St.)
1. Corridor Overview 3 Detectors Not Reporting Data 2 Detectors Not Reporting Data 0 Detectors Not Reporting Data 1 Detector Not Reporting Data 1 Detector Not Reporting Data 9th St. 18th St. Regal Valley Osborne Concord 39
2. Are the counts reasonable? NA NB NAc NBc NL EA NLc EAc EB EL EBc ELc SA SAc SL SLc WB WL WBc WLc SA and SL have far too many detections (chatter) (18th St.) Count Detector for EB counting far too few vehicles (18th St.)
2. Corridor Overview 0 Detectors Miscounting 3 Detectors Miscounting 3 Detectors Miscounting 0 Detectors Miscounting 0 Detector Miscounting 9th St. 18th St. Regal Valley Osborne Concord
3. Are all phases receiving reasonable green time? Are min times as expected? 1 EL 2 W 3 NL 4 S X WL Phase Not Active (Concord) 0:00 0:00 0:00 0:00 12:00 12:00 12:00 12:00 24:00 24:00 24:00 24:00 5 WL 6 E 7 SL 8 N
3. Corridor Overview 0 Phases Not Active 0 Phases Not Active 0 Phases Not Active 0 Phases Not Active 1 Phase Not Active 9th St. 18th St. Regal Valley Osborne Concord
4. Are the TOD plans working correctly? Coordinating 5 intersections is like trying to have 5 people record the same sequence of TV shows Only the 11:30 to 13:00 Timing Plan is Running, Intersection Free for the Rest of the Day (Concord)
4. Corridor Overview 1 TOD Plan Not Correct 0 TOD Plans Not Correct 0 TOD Plans Not Correct 1 TOD Plan Not Correct 4 TOD Plans Not Correct 9th St. 18th St. Regal Valley Osborne Concord
5. Are our green time allocations reasonable? Southbound Could Use Some More Green Time EL W NL S 100% 50% 0 Volume to Capacity Ratio 100% WL E SL N 50% 0 0:00 0:00 0:00 0:00 12:00 12:00 12:00 12:00 24:00 24:00 24:00 24:00 Time of Day
Methodology: Build From Measurable Quantities Uniform Delay g = green time (s) C = cycle length (s) X = volume to capacity ratio Measurable Quantities Volume to Capacity Ratio v = flow rate (veh/h) s = saturation flow rate (veh/h)
Eastbound V/C Ratios Morning TOD Plan Should Start Earlier
Eastbound V/C Ratios Morning TOD Plan Should Start Earlier
Is the Progression FunctioningUsing the PCD Before After 9th St. 18th St. Regal Valley Osborne Concord