FHWA System Reliability Metrics

Reliability is reported to FHWA in terms of Level of Travel Time Reliability (LOTTR), which is a ratio of person-miles traveled that are reliable to total person-miles traveled.  LOTTR is calculated using four times (including holidays):
  • Weekday 6-10am; 10am-4pm; 4-8 pm
  • Weekends 6am -8pm
More information regarding methodology is available by the FHWA

% Reliable Person-Miles  (Interstate)

% Reliable Person-Miles  (non-Interstate NHS) 

Interstate Person-Miles

Non-Interstate NHS Person-Miles