GTIS Travel Time Report #2
Statistics for Agency:IL-IDOTD8 Route:I-255

   Year        Month
Year: 2023 Month: January
Direction Segment Start Segment End
Total Length (mi)
  • Total length of all segments for the route listed (may include overlapping segments)
Total Travel Time, GTIS (min)
  • Average total travel time for all segments as reported by the Gateway Traveler Information System (GTIS)
Total Travel Time, NPMRDS (min)
  • Average total travel time for all segments as reported by the National Performance Management Research Data Set (NPMRDS)
Similarity 1 (%)
  • Based on Normalized Root Mean Square Error (NRMSE)
  • Shows how similar the values are / error in measurements
Similarity 2 (%)
  • Based on Mean Absolute Percentage Error (MAPE)
  • Shows how similar the values are / error in measurements
  • Deviation between data points in terms of percentage, effected largely by overforecasts
Abnormality (%)
  • Based on data lying outside of three standard deviations from the mean versus what would normally be expected
  • Affected by GTIS and NPMRDS evenly
Association (%)
  • Based on correlation coefficient between datasets
  • Can you predict one value based on the other
Inequality (%)
  • Based on Theil statistics for the data
  • Suite of four statistics commonly used to compare travel time data
  • Measuring covariance, variance, and bias
Bias (%)
  • Based on Theil bias statistic only
Omission (%)
  • Based on data availability
  • Large amounts of unavailable data results in lower score
Overall (%)
  • Weighted average of the seven intermediate statistics
Change From Last Month(%)
  • Percent change in overall score from previous month
NBI-64I-554.583.964.0993.9196.5695.5772.1475.7973.98100.0089.360.88
NBI-55I-2706.155.185.3794.1195.9385.9572.7178.0164.6599.7487.62-0.50
NBMississippi RiverI-6416.3214.1114.7594.8795.7092.4383.4673.5029.44100.0085.531.30
NBMississippi RiverIL-3N6.205.405.5795.6996.7186.0079.3580.2651.56100.0087.82-2.82
NBIL-3NI-6410.108.719.1993.5394.8489.2179.0572.4535.28100.0084.69-0.70
NBOverall43.3637.3738.9794.4295.9589.8377.3476.0050.9899.9587.00-1.20
SBI-270I-556.155.215.5690.2493.5692.2666.8466.9358.9098.6184.30-2.67
SBI-55I-270N/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/A
SBI-55I-644.563.904.1492.1594.2184.1476.5871.2845.51100.0084.34-0.51
SBI-64Mississippi River16.2014.0014.7294.1395.1293.6478.2073.1731.17100.0084.93-1.59
SBIL-3NMississippi River6.205.385.6192.9595.5791.2168.1875.9866.31100.0087.30-1.88
SBI-64IL-3N9.998.629.1093.7394.7082.1476.7772.9728.80100.0083.18-3.48
SBOverall43.1037.1139.1392.6494.6388.6873.3172.0646.1499.7284.81-1.20
Overall86.4674.4878.0993.5395.2989.2575.3374.0348.5699.8485.91-1.20
Cells are highlighted red when they decrease by more than -5.7 percentage points which represents the 5th percentile of monthly changes at this aggregation from 2017-2025.
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