The US Federal Railroad Administration (FRA) sponsored the first commercial version of FAST, which was created to estimate the sleep pattern of employees to assess fatigue consequences of a schedule without collecting sleep records. The FRA validated the sleep estimator for a wide range of railroad work groups and sponsored another set of studies to see if the model could predict railroad accident risk and related costs. Those studies showed that employees predicted to be the most fatigued were about 70% more likely to have an accident. In addition, accidents that were associated with low levels of predicted performance were, on average, four times more expensive than accidents by rested employees.

The implications of this study provided the science foundation for the Railroad Safety Improvement Action of 2008 and led to new passenger hours-of-service regulation that incorporates bio-mathematical modeling as a fatigue risk mitigation safeguard. FAST is one of only two validated and approved models and the one used by the FRA itself. SAFTE-FAST has rail and transit specific features, like recognition of interim release and split duties, rail specific sleep patterns, and automated calculation of the FRA established fatigue risk criterion - percent duty time below effectiveness of 70.

The District of Columbia's Washington Metro transit system (WMATA) has adopted the SAFTE-FAST system, which WMATA uses to continuously assess rail and bus operator fatigue. SAFTE-FAST findings are incorporated into an automated Fatigue Dashboard that facilitates hours-of-service implementation and regular fatigue audits, and supports fatigue risk management oversight.