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Using Ground Truth Geospatial Data to Validate Advanced Traveler Information Systems Freeway Travel Time Messages. ITE District 6 Annual Meeting July 13, 2005 Aaron Breakstone Master of Urban and Regional Planning Candidate Portland State University [email protected] - PowerPoint PPT Presentation
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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
July 13, 2005ITE District 6 Annual Meeting
Outline
• Project Overview
• Summary of Test Area
• Experimental Design
• Data Collection
• Data Comparison
• Results
• Next Steps
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
July 13, 2005ITE District 6 Annual Meeting
Next Steps
• More data– Incidents– Capture transitions
• Different algorithms
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
