In plain English
FAR 52.246-14, Inspection of Transportation, is a contract clause prescribed at FAR 46.314, most recently dated Apr 1984. The complete official text is reproduced below, verbatim, from GSA's published FAR source files.
Its text contains no sentence requiring insertion into subcontracts; see the flowdown section below for what that does and does not mean.
Does it flow down to subcontracts?
No flowdown mandate found in the clause text
We scanned the full clause text and found no sentence directing the contractor to insert this clause into subcontracts. That is a statement about the text, not legal advice: a prime contractor may still flow terms down contractually, an agency supplement (DFARS, VAAR, …) may add requirements, and clauses listed below (if any) may order this clause into subcontracts from the outside.
Where it's prescribed
As prescribed in 46.314 , insert the following clause in solicitations and contracts for freight transportation services (including local drayage) by rail, motor (including bus), domestic freight forwarder, and domestic water carriers (including inland, coastwise, and intercoastal). The contracting officer shall not use the clause for the acquisition of transportation services by domestic or international air carriers or by international ocean carriers, or to freight services provided under bills of lading or to those negotiated for reduced rates under 49 U.S.C.10721 or 1 3712 . (See part 47 , Transportation.)
Prescribing reference: FAR 46.314.
The official text, verbatim
As prescribed in 46.314 , insert the following clause in solicitations and contracts for freight transportation services (including local drayage) by rail, motor (including bus), domestic freight forwarder, and domestic water carriers (including inland, coastwise, and intercoastal). The contracting officer shall not use the clause for the acquisition of transportation services by domestic or international air carriers or by international ocean carriers, or to freight services provided under bills of lading or to those negotiated for reduced rates under 49 U.S.C.10721 or 1 3712 . (See part 47 , Transportation.)
Inspection of Transportation (Apr 1984)
The Government has the right to inspect and test the Contractor’s services, facilities, and equipment at all reasonable times. The Contractor shall furnish Government representatives with the free access and reasonable facilities and assistance required to accomplish their inspections and tests.
(End of clause)