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Evaluation of Travel Information and Prediction System (TIPS) for Work Zone Operations

Evaluation of Travel Information and Prediction System (TIPS) for Work Zone Operations. University of Maryland, College Park. TIPS overview. The messages displayed on these three PCMS are the range of travel time from each spot to Spot 5 (I-695 Gore) (e.g., “12 TO 16 MIN TO I-695”).

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Evaluation of Travel Information and Prediction System (TIPS) for Work Zone Operations

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  1. Evaluation of Travel Information and Prediction System (TIPS) for Work Zone Operations University of Maryland, College Park

  2. TIPS overview • The messages displayed on these three PCMS are the range of travel time from each spot to Spot 5 (I-695 Gore) (e.g., “12 TO 16 MIN TO I-695”). • Traffic Information and Prediction System

  3. Criteria of TIPS Evaluation • Data collection for evaluation: Testing vehicle method • TIPS Accuracy : comparing the actual measured travel times to those displayed from each PCMS. • TIPS Reliability : consistency between the travel time information reported on the website and those displayed on each PCMS. • System Accuracy and Reliability

  4. PCMS #1 PCMS #2 PCMS #3 UB UB UB LB LB LB 2400 vph 4250 vph 2650 vph 1750 vph 2200 vph 1650 vph # of incorrect 9* 8 7 # of correct 6* 27 27 System accuracy (%) 40.00 77.14 79.41 System Accuracy Evaluation on 11/14 • System Accuracy Volume difference from Sensor data (Note: “No message” data on PCMS #1 were excluded from the sample size) • The accuracy drops as PCMS #1 is far away from I-695.

  5. Deviation of predicted travel time error (sec) Frequency PCMS #1 PCMS #2 PCMS #3 PCMS #1 PCMS #2 PCMS #3 Average (seconds) 149.11 38.75 206.29 <= -480 0 1 0 Standard deviation 415.05 308.11 181.70 <= -240 2 0 0 <= 0 2 2 1 <= 240 1 2 3 <= 480 1 3 3 > 480 3 0 0 Total 9 8 7 System Accuracy Evaluation on 11/14 • Frequency distribution of predicted travel time errors • System Accuracy • Statistical analysis of predicted travel time errors

  6. PCMS #1 PCMS #2 PCMS #3 UB UB UB LB LB LB 5000 vph 4100 vph 2400 vph 1900 vph 2100 vph 1100 vph # of incorrect 8 5 4 # of correct 11 14 15 System accuracy (%) 57.89 73.68 78.95 System Accuracy Evaluation on 11/19 • System Accuracy Volume difference from Sensor data • The volume difference from the sensor data at PCMS #1 is greater than those at PCMS #2 and #3 • The accuracy drops as PCMS #1 is far away from I-695 and the volume difference increases.

  7. Deviation of predicted travel time error (sec) Frequency PCMS #1 PCMS #2 PCMS #3 PCMS #1 PCMS #2 PCMS #3 Average (seconds) -21.00 85.40 87.25 <= -480 0 0 1 Standard deviation 315.37 268.95 401.38 <= -240 1 0 0 <= 0 4 2 0 <= 240 1 2 2 <= 480 1 1 1 > 480 1 0 0 Total 8 5 4 System Accuracy Evaluation on 11/19 • Frequency distribution of predicted travel time errors • System Accuracy • Statistical analysis of predicted travel time errors

  8. PCMS #1 PCMS #2 PCMS #3 UB UB UB LB LB LB 2450 vph 2400 vph 2300 vph 1550 vph 1200 vph 1000 vph # of incorrect 0 0 2 # of correct 21 21 19 System accuracy (%) 100.00 100.00 90.48 System Accuracy Evaluation on 11/24 • System Accuracy Volume difference from Sensor data • The LB and UB of volumes are low and their differences are small, which mean that traffic conditions are uncongested and stable. • The system can achieve a high accuracy under the stable traffic flow patterns.

  9. Deviation of predicted travel time error (sec) Frequency PCMS #1 PCMS #2 PCMS #3 PCMS #1 PCMS #2 PCMS #3 Average (seconds) N/A N/A 148.00 <= -480 0 0 0 Standard deviation N/A N/A 16.97 <= -240 0 0 0 <= 0 0 0 0 <= 240 0 0 2 <= 480 0 0 0 > 480 0 0 0 Total 0 0 2 System Accuracy Evaluation on 11/24 • Frequency distribution of predicted travel time errors • System Accuracy • Statistical analysis of predicted travel time errors

  10. PCMS #1 PCMS #2 PCMS #3 UB UB UB LB LB LB 3750 vph 4300 vph 2750 vph 600 vph 1000 vph 1500 vph # of incorrect 29 12 6 # of correct 2 19 25 System accuracy (%) 6.45 61.29 80.65 System Accuracy Evaluation on 11/25 • System Accuracy Volume difference from Sensor data • The performance of such a system clearly varies with the range of flow rate variation. • PCMS #1 experiences the largest range of flow variation, and yields the poorest results.

  11. Deviation of predicted travel time error (sec) Frequency PCMS #1 PCMS #2 PCMS #3 PCMS #1 PCMS #2 PCMS #3 Average (seconds) -185.52 103.92 157.50 <= -480 12 0 0 Standard deviation 792.84 224.49 168.95 <= -240 4 0 0 <= 0 1 4 1 <= 240 1 5 4 <= 480 1 2 1 > 480 10 1 0 Total 29 12 6 System Accuracy Evaluation on 11/25 • Frequency distribution of predicted travel time errors • System Accuracy • Statistical analysis of predicted travel time errors

  12. UB PCMS #1 PCMS #2 PCMS #3 4400 vph UB UB UB LB LB LB 3000 vph 4400 vph 2700 vph 1200 vph 1100 vph 1500 vph # of incorrect 3 0 1 # of correct 10 13 12 System accuracy (%) 76.92 100.00 92.31 System Accuracy Evaluation on 12/04 • System Accuracy Volume difference from Sensor data • The accuracy drops as PCMS #1 is far away from I-695 and the volume difference increases.

  13. Deviation of predicted travel time error (sec) Frequency PCMS #1 PCMS #2 PCMS #3 PCMS #1 PCMS #2 PCMS #3 Average (seconds) -70.00 N/A 151.00 <= -480 0 0 0 Standard deviation 190.13 N/A N/A <= -240 0 0 0 <= 0 1 0 0 <= 240 1 0 1 <= 480 0 0 0 > 480 0 0 0 Total 2 0 1 System Accuracy Evaluation on 12/04 • Frequency distribution of predicted travel time errors • System Accuracy • Statistical analysis of predicted travel time errors

  14. System Accuracy Evaluation • The accuracy is often dropped for those PCMS far away from Spot 5 (I-695 Gore), or experiencing a wide range of the flow rate variation. • The system doesn’t provide reliable travel time information during congested peak hours, especially for a short peak or a transition period between off-peak and peak hours. • Conclusions

  15. PCMS #1 PCMS #1 PCMS #2 PCMS #2 PCMS #3 PCMS #3 # of Inconsistence # of Inconsistence 0 4 0 1 1 1 # of Consistence # of Consistence 9 19 19 33 18 30 System reliability (%) System reliability (%) 100.00 69.23 97.06 100.00 96.77 94.74 System Reliability Evaluation on 11/14 and 11/19 • 11/14 (Note: “No message” from the PCMS is excluded from the sample size.) • 11/19

  16. PCMS #1 PCMS #1 PCMS #2 PCMS #2 PCMS #3 PCMS #3 # of Inconsistence # of Inconsistence 24 0 1 0 1 0 # of Consistence # of Consistence 21 9 33 21 30 21 System reliability (%) System reliability (%) 100.00 27.27 97.06 100.00 100.00 96.77 System Reliability Evaluation on 11/24 and 11/25 • 11/24 • 11/25 (Note: “Blank” from the website is included from the sample size.)

  17. PCMS #1 PCMS #2 PCMS #3 # of Inconsistence 7 0 0 # of Consistence 6 13 13 System reliability (%) 46.15 100.00 100.00 System Reliability Evaluation on 12/04 • 12/04 (Note: “Blank” from the website is included from the sample size.)

  18. System Reliability Evaluation • The system reliability also show patterns similar to the system accuracy. • That is, the reliability of a PCMS decreases with its distance to Spot 5 (I-695 Gore). • Conclusions

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