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 freight, Truck Travel Time Reliability (TTTR), is the ratio of the Interstate System mileage providing for reliable truck travel times. TTTR targets for the State DOTs were adopted on October 1, 2018. The TPB adopted their own TTTR metropolitan planning area targets on July 18, 2018.
A detailed report containing the methodologies and the TPB adopted targets can be found here.