(a) Travel time data needed to calculate the Travel Time Reliability measures in §490.507(a) shall come from the travel time data set, as specified in §490.103(e).

(1) State DOTs, in coordination with MPOs, shall define reporting segments in accordance with §490.103(f). Reporting segments must be contiguous so that they cover the full extent of the mainline highways of the NHS in the State.

(2) [Reserved]

(b) State DOTs shall not replace missing travel times when data are not available in the travel time data set (data not reported, or reported as “0” or null) as specified in §490.511(b)(1)(v).

(c) AADT needed to calculate the Travel Time Reliability measures will be used, as reported to HPMS in June of the reporting year, to assign an annual volume to each reporting segment. Annual volume will be calculated as:

Annual Volume = AADT × 365 days

(d) The average occupancy factors for the State and/or metropolitan area (as applicable) needed to calculate Travel Time Reliability measures shall come from the most recently available data tables published by FHWA unless using other allowed data source(s).

(e) If an NHS roadway is closed, the State DOT is not required to include those time periods for those segments of road in the calculations required for the Level of Travel Time Reliability (LOTTR) metric (see §490.511(a)(1)).

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