(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) 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) [Reserved]
(b) [Reserved]
[82 FR 6031, Jan. 18, 2017, as amended at 83 FR 24936, May 31, 2018]