§ 490.513 Calculation of National Highway System performance measures. ( a ) The NHS Performance measures in § 490.507 shall be calculated in accordance with this section by State DOTs and MPOs to carry out the Interstate System and non-Interstate NHS performance-related requirements of this part, and by FHWA to make the significant progress determinations specified in § 490.109 and to report on system performance.
( b ) The Interstate Travel Time Reliability measure specified in § 490.507(a)(1) shall be computed to the nearest tenth of a percent as follows: Where: R = total number of Interstate System reporting segments that are exhibiting an LOTTR below 1.50 during all of the time periods identified in § 490.511(b)(1)(i) through (iv); I = Interstate System reporting segment “i”; SLi = length, to the nearest thousandth of a mile, of Interstate System reporting segment “i”; AVi = total annual traffic volume to the nearest single vehicle, of the Interstate System reporting segment “i”; J = geographic area in which the reporting segment “i” is located where a unique occupancy factor has been determined; OFi = occupancy factor for vehicles on the NHS within a specified geographic area within the State/Metropolitan planning area; and T = total number of Interstate System reporting segments.
( c ) The Non-Interstate Travel Time Reliability measure specified in § 490.507(a)(2) shall be computed to the nearest tenth of a percent as follows: Where: R = total number of non-Interstate NHS reporting segments that are exhibiting an LOTTR below 1.50 during all of the time periods identified in § 490.511(b)(1)(i) through (iv); i = non-Interstate NHS reporting segment “i”; SLi = length, to the nearest thousandth of a mile, of non-Interstate NHS reporting segment “i”; AVi = total annual traffic volume to the nearest 1 vehicle, of the Interstate System reporting segment “i”; j = geographic area in which the reporting segment “i” is located where a unique occupancy factor has been determined; OFj = occupancy factor for vehicles on the NHS within a specified geographic area within the State/Metropolitan planning area; and T = total number of non-Interstate NHS reporting segments.
( d ) The GHG measure specified in § 490.507(b) shall be computed to the nearest tenth of a percent as follows: Where: (Tailpipe CO2 Emissions on NHS)CY = total tailpipe CO2 emissions on the NHS in a calendar year (expressed in million metric tons (mmt), and rounded to the nearest hund
redth); and (Tailpipe CO2 Emissions on NHS)reference year = total tailpipe CO2 emissions on the NHS in calendar year 2022 (expressed in million metric tons (mmt), and rounded to the nearest hundredth).
( d ) The GHG measure specified in § 490.507(b) shall be computed to the nearest tenth of a percent as follows:
Where: (Tailpipe CO2 Emissions on NHS)CY = total tailpipe CO2 emissions on the NHS in a calendar year (expressed in million metric tons (mmt), and rounded to the nearest hund
redth); and (Tailpipe CO2 Emissions on NHS)reference year = total tailpipe CO2 emissions on the NHS in calendar year 2022 (expressed in million metric tons (mmt), and rounded to the nearest hundredth).
[82 FR 6031, Jan. 18, 2017, as amended at 83 FR 24936, May 31, 2018; 88 FR 85393, Dec. 7, 2023]