Bid Protest
A formal challenge by a vendor to how a solicitation was written, run or awarded. The mechanism that makes the rest of public procurement enforceable.
A protest is a losing or excluded vendor formally objecting: that the specification was written to favor a competitor, that a bid was wrongly judged responsive or non-responsive, that the evaluation departed from its published criteria, or that a sole-source justification does not hold.
Protests are why the earlier rules bind. Every requirement in this module is enforceable because a vendor can challenge it, and the possibility of that challenge is what keeps a specification defensible and an evaluation honest.
The cost to a fleet is usually delay rather than reversal. A protest can suspend an award for weeks or months, which matters enormously when a vehicle order is tied to a fiscal year or a manufacturer order bank. That timing exposure is the main practical reason to get the specification right rather than to rely on being able to defend it.
The strongest protection is documentation written at the time: why each requirement exists, how the evaluation was conducted, what was found. Reconstructing the reasoning afterwards is far weaker, and it reads that way.