NIP - Company Car Driver

Biggus_Dickus

born_again said:

Op needs to tell them, either they say who was driving or they will both be on a disciplinary. With the possibility of the sack for failing to provide the information required.

The OP has intimated it’s entirely plausible that the two employees, who work together and share driving duties, can’t be certain who the offending driver actually was. 

The drivers may be swinging the lead,...equally, they may be relating the facts truthfully.

By all means speak to the drivers individually and explain the potentially serious consequences that the OP faces but at this juncture threatening the two employees with disciplinary action/dismissal would be unwise, imho.