This restriction does not apply in any of the following circumstances:

(a) Buses manufactured outside the United States, Australia, Canada, New Zealand, or the United Kingdom are needed for temporary use because buses manufactured in the United States, Australia, Canada, New Zealand, or the United Kingdom are not available to satisfy requirements that cannot be postponed. Such use may not, however, exceed the lead time required for acquisition and delivery of buses manufactured in the United States, Australia, Canada, New Zealand, or the United Kingdom.

(b) The requirement for buses is temporary in nature. For example, to meet a special, nonrecurring requirement or a sporadic and infrequent recurring requirement, buses manufactured outside the United States, Australia, Canada, or the United Kingdom may be used for temporary periods of time. Such use may not, however, exceed the period of time needed to meet the special requirement.

(c) Buses manufactured outside the United States, Australia, Canada, or the United Kingdom are available at no cost to the U.S. Government.

(d) The acquisition is for an amount at or below the simplified acquisition threshold.