Assessment and Refinement of Real-Time Travel Time Algorithms for Use in Practice September 6, 2007

Agenda Accomplisments  TRB paper submitted Effects of Additional Detection Correlations Data Quality

Additional Detection Simulation of additional of detectors on I-5 and OR 217 Additional detectors simulated using probe vehicle speeds Terms:  Instantaneous speeds – speeds measured by detectors at time when vehicle enters segment  Real-time speeds – speeds measured by detectors at time probe passed the detector

I-5 NB SoD - Additional Detector Locations MP Macadam (299.7) Terwilliger (297.33) Capital (295.18) Spring Garden (296.26) MP – 295.5

I-5 NB SoD Appears there is some improvement when adding detector in the curves Note improvement when using real-time speeds instead of instantaneous speeds Suspect we perhaps did not catch transition periods on this segment. Or else, surprisingly, detection is ok. Midpoint Error (%) (Instantaneous speeds) Real Time Error (%) (Real-time speeds) Real Time Error – Additional detector between Terwilliger and Macadam (%) Real Time Error – Additional detector between Capital and Spring Garden (%) MAPESDPESEMAPESDPESEMAPESDPESEMAPESDPESE

I-5 SB SoD Additional Detector Locations MP 292 MP Haines (293.1) Upper Boones (291.25) MP 292

Errors due to Large Detector Spacing I-5 SB (South of Downtown) Date: 4/16/2007 Start Time: 16:19 Error: -32.2% 2.11 mi.

I-5 SB SoD Appears there is some improvement when adding detector in the curves Note improvement when using real-time speeds instead of instantaneous speeds Suspect we perhaps did not catch transition periods on this segment. Or else, surprisingly, detection is ok. Midpoint Error (%) (Instantaneous speeds)1 Real Time Error (%) (Real-time speeds) Real Time Error (%) – Additional detector south of I-5/217 junction Real Time Error (%) – Additional detector north of I-5/217 junction MAPESDPESEMAPESDPESEMAPESDPESEMAPESDPESE

I-5 SB SoD Additional detection appears to improve more than influence area adjustments Midpoint Error (%) (Instantaneous speeds) Real Time Error (%) (Real-time speeds) Real Time Error (%) – Additional detector south of I-5/217 junction Midpoint Error (%) – influence area adjustments MAPESDPESEMAPESDPESEMAPESDPESEMAPESDPESE

I-5 NB NoD - Additional Detector Locations Morrison (301.09) MP – Macadam (299.7) MP – 300.8

I-5 NB NoD Significant improvements with both locations Errors are still borderline high Midpoint Error (%) (Instantaneous speeds) Real Time Error (%) (Real-time speeds) Real Time Error – Additional detector between Morrison and Macadam (S) (%) Real Time Error – Additional detector between Morrison and Macadam (N) (%) MAPESDPESEMAPESDPESEMAPESDPESEMAPESDPESE

I-5 SB NoD - Additional Detector Locations MP – Swift/Marine (307.35) Columbia (305.97) Hood (299.25) Wheeler (302.17) MP –

I-5 SB NoD Detector between Marine/Columbia appears useful Detector at I-84 junction less useful Need to investigate additional detector locations? Marquam Bridge? Error level is still borderline high Midpoint Error (%) (Instantaneous speeds) Real Time Error (%) (Real-time speeds) Real Time Error – Additional detector between Marine and Columbia (%) Real Time Error – Additional detector near I-84 junction (%) MAPESDPESEMAPESDPESEMAPESDPESEMAPESDPESE

Effects of Additional Detection Between Macadam/ Terwilliger South of I-5/217 junction

Locations of Additional Detection Segment Description Length of Segment (mi.) Average Detector Spacing (mi.) Additional Detector Location 1 (Milepost) Additional Detector Location 2 (Milepost) I-5 NB (SoD) Terwilliger/Macadam (298.0) Capital/Spring Garden (295.5) I-5 SB (SoD) South of I-5/217 junction (292.0) North of I-5/217 junction (292.48) I-5 NB (NoD) Morrison/Macadam (300.5)Morrison/Macadam (300.8) I-5 SB (NoD) Marine/Columbia (306.5)I-84 Junction (301.25) OR-217 NB Just N of junction with I-5 (6.9) Greenburg/Scholls (4.3) OR-217 SB Walker/B-H Hwy (1.00)Allen/Denny (3.00)

Effects on Errors SegmentMidpoint Error (%)Real Time Error (%)Real Time Error with Detector at Location 1 (%) Real Time Error with Detector at Location 2 (%) MAPESDPESEMAPESDPESEMAPESDPESEMAPESDPESE OR 217 NB OR 217 SB I-5 NB SoD I-5 SB SoD I-5 NB NoD I-5 SB NoD

Correlation Investigations All Runs I-5 NB SoD I-5 SB SoD I-5 NB NoD I-5 SB NoD 217 NB217 SB Average loop speed Average probe speed Stddev probe speed Estimated travel time Minimum loop speed

Minimum Speed vs. Error Correlation Coefficient

I-5 SB SoD Avg Probe Speed vs. Error

I-5 NB NoD Problem location was always between Morrison and Macadam

Going Forward Goals Identified Last Meeting  Estimate benefit of additional detection Simulated additional detectors for I-5 and 217  Try to answer question “under what conditions does algorithm accuracy degrade” Some correlation found when broken down by segment To do: correlate with rate of change of speed at detector station  Algorithm refinement based on those two questions Where do we go from here?

Overall Result Summary Segment Description Avg Detector Spacing (mi.) MAPESDPEMPESENum Runs Percent Estimates with Error < 20% Percent Estimates with Error < 30% I-5 NB SoD I-5 SB SoD I-5 NB NoD I-5 SB NoD OR 217 NB OR 217 SB I-84 EB I-84 WB I-205 NB I-205 SB I-405 NB I-405 SB US 26 EB US 26 WB

Data Quality Trying to understand and improve data quality Visit from UW-researchers in September to investigate potential calibration issues Hoping to create data quality reports useful to ODOT Following slides demonstrate types of detector issues currently observed

I-5 NB Denver Ave – Speed & Occupancy I-5 NB at Denver Ave Milepost: Number of Lanes: 3 Plots show all lanes; These speeds appear somewhat suspect; in previous observations, speeds appeared less suspect. Speed vs. TimeOccupancy vs. Time

I-5 NB Terwilliger Blvd – Speed & Occupancy I-5 NB at Terwilliger Blvd Milepost: Number of Lanes: 3 Plots show all lanes. Speed vs. TimeOccupancy vs. Time

I-205 NB at Johnson Creek Low nighttime speeds are a serious problem at this detector. Daytime speeds look reasonable. Lane 3 shows similar issues, lane 1 shows fewer issues with low nighttime speeds. Plots for one day only; however, issues are consistent across multiple days. I-205 NB at Johnson Creek Milepost: 16.2 Number of Lanes: 3 Note: station does show congestion on Aug 31, second speeds for Lane 2; midnight to 5am, Aug 15, second speeds for Lane 2; entire day of Aug 15, 2007.

Lane 3, Occupancy vs. TimeLane 3, Speed vs. Time I-84 WB – Sandy – Lane 3 Lane 3 exhibits high number of occupancy readings > 95%. I-84 WB at Sandy Blvd Milepost: 2.4 Number of Lanes: 3

I-84 WB – Sandy – Lanes 1 and 2 Lane 1, Speed vs. Time Lane 1 and Lane 2 exhibit a 20mph difference in free flow speeds. Lane 1 and Lane 2 also exhibit - low maximum occupancies. Lane 2, Speed vs. Time I-84 WB at Sandy Blvd Milepost: 2.4 Number of Lanes: 3

I-5 NB – Spring Garden St Lane 2 – Flow vs. Occupancy Lane 3 Flow vs. Occupancy Lane 3 exhibits an unusually flow/occupancy ratio. I-5 NB at Spring Garden Milepost : Number of Lanes: 3 Plots from August 3, 2007

I-205 SB – ORE 224/82 nd Ave Spd > 100 Lane 1 exhibits a high number of readings with speed > 100. Lane 1 speeds differ significantly from lane 2 speeds. I-205 SB at ORE 224/82 nd Ave Milepost: Number of Lanes: 3 Lane 1, Speed vs. TimeLane 2, Speed vs. Time

I-84 EB – 16th Lane 3 exhibits high number of readings with occupancy > 95%; lane 1 exhibits high number of readings with volume > 17, Lanes 1 and 3 exhibit high number of readings with speed = 0 and volume > 0. This detector generally appears problematic – perhaps this detector is degrading? I-84 EB at 16th Milepost: 1.3 Number of Lanes: 3 Lane 1, Volume vs. TimeLane 2, Volume vs. Time

I-5 NB - Multnomah Lanes 1 and 3 exhibit a high number of readings with occupancy > 95%. Lanes 1 and 3 behave very differently from lane 2. I-5 NB at Multnomah Milepost: 1.3 Number of Lanes: 3 Lane 2, Speed vs. TimeLane 3, Speed vs. Time

I-5 NB - Multnomah Lanes 1 and 3 exhibit a high number of readings with occupancy > 95%. Lanes 1 and 3 behave very differently from lane 2. I-5 NB at Multnomah Milepost: 1.3 Number of Lanes: 3 Lane 2, Occupancy vs. TimeLane 3, Occupancy vs. Time

I-5 NB - Multnomah 20-second occupancies, July 9, 2007 I-5 NB at Multnomah Milepost: 1.3 Number of Lanes: 3 Lane 3, Occupancy vs. Time, 7-8AMLane 3, Occupancy vs. Time

OR 217 SB – Walker Rd Lane 2 speeds from July 9, 2007 – Aug 3, 2007 Lane 2 exhibits an unusually high flow occupancy ratio. Lane 1 and Lane 3 also exhibit similar behavior. OR 217 SB at Walker Rd Milepost: 0.76 Number of Lanes: 3

I-205 NB at Glisan Lane 1 20-sec speeds Aug 15, 2007 Lanes 1 and 2 exhibit an unusually high flow occupancy ratio. I-205 NB at Glisan Milepost: Number of Lanes: 3

Selected Stations HighwayLocationMilepostLane Number* Reason SelectedStationid (Detectorids) I-5 NBDenver Ave306.51AllObserved anomalies1022 (1204, 1205, 1206) I-5 NBTerwilliger Blvd297.33AllObserved anomalies1013 (1129, 1130, 1131) I-84 WBSandy Blvd2.43 (also 1 & 2) High number of readings with occupancy > 95% 1061 (1474) I-5 NBSpring Garden Unusually high flow/occupancy ratio1011 (1115) I-205 SBORE 224/82 nd Ave High number of readings with speed > (1938) I-84 EB16 th EB1.331,3Several issues – see detailed slide1056 (1432, 1434) I-5 NBMultnomah296.61,3High number of readings with occupancy > 95% 1012 (1121, 1123) OR 217 SBWalker Rd0.762Unusually high flow/occupancy ratio1080 (1552) I-205 NBGlisan21.121,2Unusually high flow/occupancy ratio1142 (1949, 1950) I-205 NBJohnson Creek16.2Observed low nighttime speeds.1046 * I-5 NBORE 217/Kruse Way ,3Observed low nighttime speeds.1007 (1074, 1075) I-5 NBUpper Boones Overnight low speeds are less of a problem1006 (1058) I-5 NBCapitol Hwy Observed low nighttime speeds1010 (1106) *Lane 1 is the left-most lane

I-5 NB SoD MP MP – Macadam (299.7) Terwilliger (297.33) Capital (295.18)

I-5 SB SoD MP 292 MP Haines (293.1) Upper Boones (291.25)

OR 217 NB MP 6.9 MP 4.3 Scholls (3.85) Greenburg (4.65)

OR 217 SB B-H Hwy (1.92) MP 1.00 MP 3.00 Walker (0.76) Allen (2.55) Denny (3.12)

Overview - Recap

Potential Solutions Errors due to changes in conditions  Short Term Trending  Historical Data Errors due to non-functioning detectors  Low cost portable detectors  Historical Data Errors due to large detector spacing  Additional Detection

Sources of Estimation Errors Detailed analysis of high error runs on  I-5 ( Sections both north and south of downtown)  OR – 217 (NB & SB) Three main sources of errors  Errors due to changes in conditions  Errors due to non-functioning detectors  Errors due to large detector spacing

Errors due to Changes in Conditions I-5 NB North of Downtown Date: 4/24/2007 Start Time: 17:47 Error: 27.13%

Errors due to Non-Functioning Detectors OR-217 NB Date: 4/16/2007 Start Time: 16:16 Error: % Missing Detectors

Errors due to Large Detector Spacing I-5 SB (South of Downtown) Date: 4/16/2007 Start Time: 16:19 Error: -32.2% 2.11 mi.

Probe Travel Time vs. Error

Midpoint Travel Time vs. Error

Average Speed vs. Error

Speed Differential vs. Error (I-5 High Error Runs Only)

Speed Differential vs. Error (I-5 High Speed Differential Runs Only)