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Assessment and Refinement of Real-Time Travel Time Algorithms for Use in Practice January 10, 2007
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Agenda Other States’ Efforts (15 minutes) Data Collection & Analysis Update (20 minutes) OTREC Proposal (10 minutes) INRIX Follow-Up (5 minutes) Deliverables (5 minutes) Next Steps (5 minutes)
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Best Practices – Other States..
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Travel Time Status Alaska Hawaii Puerto Rico D.C. = Provide Travel Times (25) = Plans to Provide Travel Times (17) September 15, 2006
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Methods… Two main approaches for generating travel times In house Loop Detectors Video Detectors RTMS Toll Tags Private providers Smartroute Systems Inrix Traffic.com
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What others are doing…. In house Milwaukee San Antonio Chicago Atlanta Nashville Houston Private Providers Boston Miami St. Louis North Carolina New Jersey
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Milwaukee, WI Detector Spacing 0.25 miles in urban areas 2 miles in rural areas Data from detectors transmitted to Traffic Operations Center Freeway Traffic Management System (FTMS) Server Travel Time = Known Distance/Average Speed Website updated every 3 minutes DMS signs updated every 1 minute No probe vehicle data; all detector derived travel times
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San Antonio, TX Travel Times calculated from/to major interchanges Detectors Loop Detectors Video Detectors Point travel speeds used to calculate times from detector to detector based on distance between detectors Travel times displayed on mainlane DMS from 6:00 a.m. to 10:00 p.m., seven days of the week Travel times posted on TransGuide website use the same algorithm
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Data Calculation Travel Time Calculation- - Segment travel speed is chosen as lower of upstream and downstream sensor speed - Point to point travel speed is summation of segment travel times Source: San Antonio TransGuide Travel Time Algorithm
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Chicago, IL IPASS Data Travel times from toll plaza to toll plaza Based on toll transponder data collected by ETC system > 1.5 million users on tollways Significant number of probe vehicles provide time stamp and location Travel times calculated using location and time stamp information High quality of data RTMS Data IDOT Loop detector data
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Travel Time Estimation Toll network Roadway segments Bounded by ramps and plazas IPASS & RTMS data Provide redundancy on certain segments Travel time software allows choice of data DMS Travel Times From all three sources (I-PASS, RTMS, Loops) GCM Webpage Only I-PASS travel times
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Houston, TX AVI Toll Transponders Approximately 2 million transponders Data collected at 232 reader stations and transmitted to Transtar TMC Reader stations 2-3 miles apart Automated Travel Time Processor Posts travel times to 81 DMS signs every 10 minutes (5:30 a.m. – 7:30 p.m.) Some signs updated more frequently than others
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Nashville, TN Technology RTMS detectors at 0.25 mile spacing Speeds Ensure data quality by regular calibration CCTV cameras Travel Time verification Data Collection & Processing Average speed from RTMS every 2 minutes Travel time calculation Average speed and distances between sensors Travel Times 2-3 minute ranges Segments < 5 miles
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Atlanta, GA Changeable Message Signs (CMS) All major freeways HOV CMS Information for express lane commuters Automatic message generation Travel Times between 6 a.m. – 9 p.m. Average speeds from Video Detection Cameras Incident Messages Incident location Number of lanes affected
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Technology VDS Cameras Monitoring and Video Detection Cameras Fixed black and white cameras Placed along all major freeways Provide volumes and speeds Source: http://www.georgia-navigator.com/about.shtml
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San Francisco - Bay Area, CA Existing Caltrans System Dual Loop Detectors Speeds New MTC System Antennas to read FasTrak Toll Tags Average Travel Times and speeds of all vehicles 511 System Combination of data from both sources to calculate travel times
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Seattle, WA Loop Detectors Speeds Travel Times Current Times Speed of two adjacent stations is averaged Distance/Average Speed = Travel Time Adjustment Average Travel Times for each route by time of departure Determination of future conditions based on historical data Conditions worsen – adjustment is made Conditions get better – no adjustment is made
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Data Collection Dates: Thursday Dec 21, 2006; Tuesday Jan 9, 2007 Times: 7-9 AM, 4-6 PM both days Route: Drivers drove loop on I-5 South of Downtown (Tualatin-Sherwood – I-405) Method: Data collected using Garmin iQues – record lat/lon and speed every 3 seconds One iQue may be malfunctioing Two new iQues ordered – should be here soon Have around 15 runs for each segment of the I- 5 corridor (south of downtown)
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Data Analysis Data storage and initial analysis procedures developed Fix issues we had with previous analysis Analysis must be automated Scripts written to extract data from csv files from iQues and insert data into the Portal database Database tables for storing information about Raw data files (names, times, who collected, etc.) Segments Mapping between segments and stations and station lengths Easy to manipulate station lengths Raw data Travel times – ground truth and estimates
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Two I-5 Segments I-5 NB Segment I-5 NB from VMS N of Tualatin-Sherwood to I-405 junction Milepost 290.9 to 299.8 I-5 SB Segment I-5 SB from VMS N of Terwilliger to Tualatin Sherwood exit Milepost 298 to 289.6 Also have start and ending points in lat/lon
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Next: Segment Details I-5 NB first Table of travel times Timeseries speed Plots of trajectories and speeds I-5 SB second Table of travel times Timeseries speed Plots of trajectories and speeds
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I-5 NB – VMS to I-405 – Travel Times RunDateTimeGround Truth Avg speed MidpointErrorError Pct 11-2-079:1816:1532.715:18-00:575.8% 21-3-079:1610:3649.2610:04-00:325.0% 31-4-078:4923:5421.8524:37 00:433.0% 412-21-067:1010:2749.3510:20-00:071.1% 512-21-067:4113:0040.4314:49 1:4914.0% 612-21-068:1011:0047.3311:40 00:40 6.1% 712-21-068:39 9:0657.65 9:45 00:39 7.1% 812-21-0616:3312:4540.9611:41-01:04 8.4% 912-21-0617:2123:0622.6222:37-00:29 2.1% Positive numbers indicate travel time was over-estimated (too high)
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I-5NB – December 21, 2006 Timeseries – Speed – Shows level of congestion on I-5 NB on Dec 21, 2006
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Run 5 – I-5 N – Trajectories Date: 12-21-06 Start: 7:41 Ground truth: 13:00 (780 sec) Midpoint3: 14:49 (889 sec)
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Run 5 – I-5 N – Speeds
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Speeds – Station 1014 – MP 297.33 Probe enters segmentProbe crosses detector
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Run 9 – I-5 N – Trajectories Date: 12-21-06 Time: 17:21 Ground truth: 23:06 (1386 sec) Midpoint3: 22:37 (1357 sec)
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Run 9 – I-5 N – Speeds
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I-5 SB – VMS to I-205 – Travel Times RunDateTimeGround Truth Avg speed Midpoin t ErrorErrorpct 1012-21-067:28 8:4855.5 9:40 00:529.8% 1112-21-067:59 8:3057.3 9:18 00:489.4% 1212-21-068:27 8:0660. 9:31 01:2517.5% 1312-21-068:53 8:1559. 9:23 01:0813.7% 1412-21-0616:1316.4229.313:25- 03:1719.7% 1512-21-0616:5819:3624.919:09- 00:27 2.3% 1612-21-0617:5212:2739.413:19 00:52 7.0%
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I-5SB – December 21, 2006
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Run 13 – I-5 S – Trajectories Date: 12-21-06 Time: 8:53 Ground truth: 8:15 (495 sec) Midpoint3: 9:23 (563 sec)
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Run 14 – I-5 S – Trajectories Date: 12-21-06 Time: 16:13 Ground truth: 13:00 (780 sec) Midpoint3: 14:49 (889 sec)
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Run 14 – I-5 S – Speeds
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Run 15 – I-5 S – Trajectories Date: 12-21-06 Time: 16:58 Ground truth: 19:36 Midpoint3: 19:09
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Run 15 – I-5 S – Speeds
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Data Collection – Next Steps Collect more data Corridor? I-205? (217 still under construction) Incorporate old data into new analysis system Complete analysis
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OTREC Proposal Issues Scope Extension Phasing/Budget
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OTREC Proposal - Scope Current Scope Assess and improve travel time algorithms Scope extension for OTREC Travel Time Prediction Use historical data to improve prediction of near-term travel times Should I leave work now or should I wait half an hour? Longer-term prediction will also be incorporated I’m going to the airport Friday at 4:30 – how long should I allow? Useful and difficult from a research perspective Comments: Current scope probably not sufficient for OTREC Think we need research component and student support to obtain OTREC funding
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OTREC Proposal - Budget Have ~$57,000 in match Current project ends June 30, 2006 OTREC year one ends Sept 30, 2007 Difficult to spend full $57,000 by then Propose: Phase 1 – OTREC Year 1 - $25,000 through Sept 30, 2007 Phase 2 – OTREC Year 2 - $32,000 through Jan 30, 2008 Budget breakdown similar to current budget $5,000 data collection ($10,000 total) Kristin 0.25 time Sirisha + 1 other student
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Deliverables Task 1 – ITS Data Fidelity – Submitted Task 2 – Ground Truth Data Collection – In Process Task 3 – Sensitivity Analysis – Submitted Task 4 – Algorithm Refinement Task 5 – Detailed Comparison of Algorithms Task 6 – Draft Final Report Task 7 – Final Report
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Next Steps Additional Ground Truth Collection Analysis of Ground Truth Data Follow-up with Inrix Comments??
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