This rulemaking would seek additional comment on one of the measures established in the Transportation Performance Management regulations to assess the performance of the NHS under the NHPP, is Percent Change in Tailpipe CO₂ Emissions on the NHS from the Calendar Year 2017 (also referred to as the GHG measure). This measure is calculated using data on fuel use and VMT. This rulemaking provides additional opportunity for comment. Additional information will aid FHWA in determining whether the measure should be retained, revised, or repealed.