1. (a) The performance measures are applicable to those portions of the mainline highways on the NHS as provided in paragraphs (a)(1) and (2) of this section (and in more detail in § 490.507):

   1. (1) The Travel Time Reliability measures in § 490.507(a) are applicable to all directional mainline highways on the Interstate System and non-Interstate NHS.
   2. (2) [Reserved]
2. (b) [Reserved]

[82 FR 6031, Jan. 18, 2017, as amended at 83 FR 24936, May 31, 2018; 88 FR 85392, Dec. 7, 2023; 90 FR 16466, Apr. 18, 2025]