[MICRO] = ((525,600-(T_outage-T_excluded))/525,600) * 100
where:
[MICRO] = port uptime percentage,
T_outage = total minutes of outage in previous year, and
T_excluded = total minutes of outage in previous year caused by the following reasons outside the charging station operator's control, provided that the charging station operator can demonstrate that the charging port would otherwise be operational: electric utility service interruptions, failure to charge or meet the EV charging customer's expectation for power delivery due to the fault of the vehicle, scheduled maintenance, vandalism, or natural disasters. Also excluded are hours outside of the identified hours of operation of the charging station.
23 C.F.R. §680.116