Travel Time Reliability Reference Manual/Example Data
Below are graphs and data for an 6-lane urban freeway (I-43/I-894 near Milwaukee) and 4-lane inter-regional (I-94 west of Eau Claire). All data comes from the NPMRDS data set in January 2012.
6-lane urban freeway (4.35 miles) Free flow travel time is based on the 70th percentile travel time
Reliability Index | Value |
---|---|
TTI | 1.01 |
BI | 0.26 |
OPT | 94.90 |
PTI | 1.27 |
TTI80 | 1.02 |
MI | 1.40 |
Travel Time in minutes | |
---|---|
Mean | 4.58 |
Free Flow | 4.55 |
95th % | 5.76 |
80th % | 4.65 |
97.5th % | 6.47 |
4-lane interregional freeway (20.18 miles) Free flow travel time is based on speed limit of 65mph
Reliability Index | Value |
---|---|
TTI | 1.03 |
BI | 0.06 |
OPT | 98.40 |
PTI | 1.09 |
TTI80 | 1.038 |
MI | 1.150 |
Travel Time in minutes | |
---|---|
Mean | 19.26 |
Free Flow | 18.63 |
95th % | 20.38 |
80th % | 19.33 |
97.5th % | 21.42 |
The 3-D graphs below show travel times by day and by hour for each corridor. Visually, one can see the better reliability of the inter-regional corridor over the urban. Blank areas represent points where real-time data did not exist along the entire corridor.
Travel Times for 6-lane Urban Freeway in January 2012
Travel Times for 4-lane Inter-regional Freeway in January 2012