Section 490.503 - Applicability(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) The Greenhouse Gas (GHG) measure in § 490.507(b) is applicable to all mainline highways on the Interstate and non-Interstate NHS. 82 FR 6031 , Jan. 18, 2017, as amended at 83 FR 24936 , May 31, 2018 83 FR 24936, 5/31/2018; 88 FR 85392, 1/8/2024