The final rule for system performance was published on January 18, 2017 and became effective on May 20, 2017. The target for System Performance concerning the level of congestion on the NHS, Travel Time Reliability (TTR), is the percent of person-miles traveled on both the Interstate and Non-Interstate on the NHS. State DOTs adopted TTR targets on October 1, 2018. The TPB adopted their own TTR metropolitan planning area targets on July 18, 2018.
A report detailing the methodologies and the TPB adopted targets can be found here.
TPB staff will continue to coordinate with State DOTs for both the requirements and data needs for this performance measure.