![Page 1: ITE District 6 Annual Meeting July 13, 2005 Aaron Breakstone](https://reader036.vdocument.in/reader036/viewer/2022081419/56815959550346895dc696d2/html5/thumbnails/1.jpg)
July 13, 2005ITE District 6 Annual Meeting
Using Ground Truth Geospatial Data to Validate Advanced Traveler Information Systems Freeway Travel Time MessagesITE District 6 Annual MeetingJuly 13, 2005
Aaron Breakstone Master of Urban and Regional Planning CandidatePortland State [email protected]
Chris Monsere, Ph.D., P.E.Research Assistant Professor, Portland State University
Robert L. Bertini, Ph.D., P.E.Associate Professor, Portland State UniversityDirector, Center for Transportation Studies
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July 13, 2005ITE District 6 Annual Meeting
Outline
• Project Overview
• Summary of Test Area
• Experimental Design
• Data Collection
• Data Comparison
• Results
• Next Steps
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July 13, 2005ITE District 6 Annual Meeting
Project Overview
Goals
1. Evaluate Oregon Department of Transportation’s (ODOT) travel time estimating and reporting capabilities
2. Identify locations where additional detectors might improve estimates
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July 13, 2005ITE District 6 Annual Meeting
Project Overview
• ODOT Region 1 Traffic Management Operations Center (TMOC) – 485 inductive loop detectors – 19 variable message signs
(VMS), 3 currently displaying travel times
– Advanced Traveler Information Systems (ATIS): www.TripCheck.com
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July 13, 2005ITE District 6 Annual Meeting
Project Overview
• Funded by NSF• Direct fiber-optic
connection between ODOT and PSU
• 20-second loop detector data– Volume– Speed– Occupancy
• Customized travel time area
Portland Regional Transportation Archive Listing (PORTAL) http://portal.its.pdx.edu
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July 13, 2005ITE District 6 Annual Meeting
Summary of Test Area
• 18 original directional freeway links
• 3 links eliminated– Construction – Detectors not functional– Not pertinent to study
Downtown Portland
£¤26
217
§̈¦5
§̈¦5§̈¦205
§̈¦84
§̈¦5
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July 13, 2005ITE District 6 Annual Meeting
Experimental Design• Analysis of PORTAL
estimates to determine required number of runs
• Data collection plan– 5-10 runs required for
most links– 4 routes designed– Transitional periods
targeted– Groups with 5-7 minute
headways– Standard probe vehicle
instructions
217 Southbound: US26 Interchange to I-5 Interchange [Link 9]
0
10
20
30
40
50
60
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00
Time
Tra
ve
l T
ime
s
Cu
mu
lativ
e T
rav
el T
ime
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July 13, 2005ITE District 6 Annual Meeting
Data Collection• Hardware
– Palm handheld computers
– Magellan GPS devices
• Software– ITS-GPS
Free! Available at www.its.pdx.edu
• Individual runs and groups of probe vehicles
• Variety of traffic conditions
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July 13, 2005ITE District 6 Annual Meeting
Data Collection• 87 probe vehicle runs• 904 minutes (~15 hours) of collection time• 516 miles of data• 12 drivers• 7 days
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July 13, 2005ITE District 6 Annual Meeting
Data Comparison• Probe data
– Individual runs downloaded
– Runs plotted on freeway network map showing link endpoints
– Pertinent data segments extracted
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July 13, 2005ITE District 6 Annual Meeting
Data Comparison• Detector data
– Assignment of influence areas1. Midpoint method
2. ODOT modified midpoint method
– Aggregation1. Nearest 20-second interval
2. Average of nearest interval and 1 minute before
3. Average of nearest interval and 3 minutes before
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July 13, 2005ITE District 6 Annual Meeting
Results• ATMS estimates reasonably accurate
P- Value -Statistical Significance
Link Number Midpoint ODOTMidpt -1
minMidpt -3
minODOT -1
minODOT -3
minLINK 2 - I-5 NB 0.073 0.103 0.034 0.071 0.038 0.079LINK 3 - I-5 NB 0.272 0.012 0.214 0.202 0.010 0.035LINK 4 - I-5 NB 0.651 0.665 0.545 0.287 0.560 0.301LINK 5 - I-5 SB 0.470 0.470 0.503 0.256 0.503 0.256LINK 6 - I-5 SB 0.435 0.095 0.676 0.605 0.052 0.045LINK 7 - I-5 SB 0.009 0.009 0.021 0.016 0.021 0.016LINK 8 - OR-217 NB 0.016 0.011 0.012 0.024 0.009 0.011LINK 9 - OR-217 SB 0.381 0.040 0.199 0.159 0.146 0.205LINK 10 - I-205 NB 0.532 0.460 0.277 0.040 0.896 0.965LINK 12 - I-205 SB 0.537 0.020 0.478 0.731 0.003 0.003LINK 13 - I-84 EB 0.273 0.070 0.518 0.402 0.098 0.077LINK 14 - I-84 WB 0.736 0.736 0.754 0.530 0.754 0.530LINK 16 - US 26 EB 0.026 0.026 0.009 0.012 0.009 0.012LINK 17 - US 26 WB 0.013 0.013 0.014 0.012 0.013 0.011
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July 13, 2005ITE District 6 Annual Meeting
Results• ATMS estimates reasonably accurate
Run 1
303.5
304.0
304.5
305.0
305.5
306.0
306.5
307.0
307.5
308.0
8:03:00 8:05:00 8:07:00 8:09:00 8:11:00 8:13:00 8:15:00 8:17:00 8:19:00 8:21:00
Time
Mile
po
st
Run 9
0.3
0.8
1.3
1.8
2.3
2.8
3.3
16:30:00 16:32:00 16:34:00 16:36:00 16:38:00 16:40:00 16:42:00 16:44:00 16:46:00 16:48:00
Time
Mile
post
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July 13, 2005ITE District 6 Annual Meeting
Results• Detector density and location critical
Run 7
292.3
293.3
294.3
295.3
296.3
297.3
298.3
299.3
300.3
8:05:00 8:10:00 8:15:00 8:20:00 8:25:00 8:30:00
Time
Mile
post
Run 1
303.5
304.0
304.5
305.0
305.5
306.0
306.5
307.0
307.5
308.0
8:06:00 8:08:00 8:10:00 8:12:00 8:14:00 8:16:00
Time
Mile
post
Run 6
68.9
69.4
69.9
70.4
70.9
71.4
71.9
72.4
72.9
8:17:00 8:18:30 8:20:00 8:21:30 8:23:00 8:24:30 8:26:00 8:27:30
Time
Mile
post
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July 13, 2005ITE District 6 Annual Meeting
Results• Incidents difficult to capture
Run 1
69.7
70.2
70.7
71.2
71.7
72.2
72.7
73.2
73.7
16:26:00 16:28:00 16:30:00 16:32:00 16:34:00 16:36:00 16:38:00 16:40:00 16:42:00
Time
Mile
post
Run 3
0.3
1.1
1.9
2.7
3.5
4.3
5.1
5.9
6.7
8:18:00 8:23:00 8:28:00 8:33:00 8:38:00 8:43:00 8:48:00 8:53:00 8:58:00
Time
Mile
post
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July 13, 2005ITE District 6 Annual Meeting
Results• No uniform difference between methods• Aggregation improves accuracy
-65%
-55%
-45%
-35%
-25%
-15%
-5%
5%
15%
25%
35%
45%
55%
65%
1 2 3 4 5 6 7 8 9 12 13 14 16 17
Link
Per
cen
t E
rro
r
Midpoint
ODOT
Midpt -1 min
Midpt -3 min
ODOT -1 min
ODOT -3 min
Travel Time Observations (95% CI)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
Probe Midpoint ODOT Midpt -1
min
Midpt -3
min
ODOT -1
min
ODOT -3
min
Travel Time Differences
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
Midpoint ODOT Midpt -1
min
Midpt -3
min
ODOT -1
min
ODOT -3
min
AVG MIN MAX
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July 13, 2005ITE District 6 Annual Meeting
ResultsCandidate locations for increased detection
– Recurring congestion– Detector spacing > 1 mile
1. Hwy 217 NB at MP 3.22. US-26 EB at MP 703. US-26 WB at MP 694. US-26 WB at MP 705. I-5 NB at MP 298.56. I-5 SB at MP 306.57. I-84 EB at MP 2.0
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July 13, 2005ITE District 6 Annual Meeting
Next Steps
• More data– Incidents– Capture transitions
• Different algorithms
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July 13, 2005ITE District 6 Annual Meeting
Acknowledgements
• Oregon Department of Transportation– Stacy Shetler– Galen McGill– Dennis Mitchell– Jack Marchant
• Castle Rock
Consultants– Dean Deeter
• Volunteer drivers