1. June 2006 ITE District 6 Annual Meeting June 26 2006 1 Evaluation of Single-Loop Detector Vehicle-Classification Algorithms using an Archived Data User Service System Benjamin Auffray, Kristin A. Tufte, Zachary Horowitz, Spicer Matthews, Robert L. Bertini Portland State University June 2006, ITE District 6 Annual Meeting

2. June 2006 ITE District 6 Annual Meeting June 26 2006 2 Presentation outline Introduction Project Background Data Collection Results Conclusions Next Steps Acknowledgements

3. June 2006 ITE District 6 Annual Meeting June 26 2006 3 Why collect freight data? Economic importance Lack of knowledge of freight transportation system operation Safety and security Positive affects on overall transportation system

4. June 2006 ITE District 6 Annual Meeting June 26 2006 4 Project background Basic idea: Record freeway traffic in order to compare truck counting methods 3 methods: 1) Manual 2) Autoscope “speed” and “count” detectors 3) Nihan-Wang algorithm (UW)

5. June 2006 ITE District 6 Annual Meeting June 26 2006 5 Data sources PORTAL Portland area traffic data archive Collects volume & occupancy data at 20 second intervals ODOT surveillance CCTV network About 80 cameras on local highways Recorded to DVD Used for both manual counts and Autoscope Autoscope Recorded video data processed using RackVision and accompanying software

6. June 2006 ITE District 6 Annual Meeting June 26 2006 6 Site selection 4 locations in Portland, OR I-5 SB at Marine Dr. I-84 WB at Sandy Blvd/37 th I-5 NB at Lower Boones Fy. OR-217 at SW Hall Blvd 10 days over 4 weeks Traffic recorded primarily From noon to 5 pm

7. June 2006 ITE District 6 Annual Meeting June 26 2006 7 Data organization and processing Manual count data sorted by: Lane Vehicle type (short / long / combined) Cumulative and oblique plots Histogram of Autoscope speed detector data used for length determination in some cases

8. June 2006 ITE District 6 Annual Meeting June 26 2006 8 Graphical plots Cumulative count of all vehicles Oblique graph of all vehicles plotted using a scaling factor Oblique graph of short vehicles using a scaling factor

9. June 2006 ITE District 6 Annual Meeting June 26 2006 9 Comparison data Comparison of total count mechanisms to ground truth Truck count percent difference

10. June 2006 ITE District 6 Annual Meeting June 26 2006 10 Comparison data Measured average speed relation to all count error Comparison by site

11. June 2006 ITE District 6 Annual Meeting June 26 2006 11 Conclusions Nihan-Wang estimations Unusually large error for some speeds and counts Detector issues such as loop sensitivities Incorrect or missing data Autoscope Difficulties in calibration and data processing Returned some favorable results compared to ground truth ODOT surveillance camera system not ideal for Autoscope Manual counts still produce best data

12. June 2006 ITE District 6 Annual Meeting June 26 2006 12 Next steps Additional data collection Detector fidelity is key Different sites may produce better data Vehicle classification by type Further statistical testing PORTAL data calibration will improve Nihan-Wang algorithm implementation results Travel time estimation for freight vehicles Permanent, automated freight vehicle counting Ramp meter speed trap installations

13. June 2006 ITE District 6 Annual Meeting June 26 2006 13 Acknowledgements ODOT TMOC Staff Dr. Robert Bertini PORTAL Team: Dr. Kristin Tufte Spicer Matthews Zachary Horowitz

14. June 2006 ITE District 6 Annual Meeting June 26 2006 14 References [1] Y. Wang and N. Nihan. Dynamic estimation of freeway large truck volume based on single-loop measurements. CD-Rom for the 80th Annual Meeting of TRB, paper 01-2853, TRB, National Research Council, Washington D.C., 2001. [2] Kwon, Jaimyoung. Joint Estimation of the Traffic Speed and Mean Vehicle Length From Single-Loop Detector Data. CD- Rom for the 82nd Annual Meeting of TRB, National Research Council, Washington, D.C. 2003. [3] Kwon, Jaimyoung; Varaiya, P. P.; Skabardonis, Alexander. ESTIMATION OF TRUCK TRAFFIC VOLUME FROM SINGLE LOOP DETECTOR USING LANE-TO-LANE SPEED CORRELATION. CD-Rom for the 82nd Annual Meeting of TRB, National Research Council, Washington, D.C. 2003. [4] Nihan, NL; Wang, Y; Zhang, XP. EVALUATION OF DUAL-LOOP DATA ACCURACY USING VIDEO GROUND TRUTH DATA. TransNow, Transportation Northwest, Washington Univ, Civil Engineering Dept, 2002. [5] Y. Wang and N. Nihan. Can Single-Loop Detectors Do the Work of Dual-Loop Detectors? ASCE Journal of Transportation Engineering, 129(2), 169-176, 2003 [6] National ITS ADUS Addendum [7] S. Turner. Guidelines for Developing ITS Data Archiving Systems. Report 2127-3. FHWA, U.S. Department of Transportation, Texas Department of Transportation and Texas Transportation Institute, 2001. [8] Y. Wang and N. Nihan. A Robust Method of Filtering Single-Loop Data for Improved Speed Estimation. CD-Rom for the 81st Annual Meeting of TRB, paper 02-3843, TRB, National Research Council, Washington, D.C. 2002. [9] P. Athol. Interdependence of Certain Operation Characteristics within a Moving Traffic Stream. Highway Research Record 72, 58-87.

15. June 2006 ITE District 6 Annual Meeting June 26 2006 15 Questions and Comments