Hours of service (HOS)

Definition

Federal limits on how long a commercial driver may drive and work.

Why It Matters

Hours of service is the ceiling on a trucking company's capacity, and it is why revenue growth at a carrier has to be read against headcount. A fleet already running its drivers to the weekly limit cannot grow by asking for more; it grows by hiring, which is a cost the seller's trailing numbers may not carry. Electronic logs make the record auditable, so this is one of the few operating claims in diligence a buyer can check instead of believe, and a pattern of edits or unassigned driving time is what to look for.

In numbers: A fleet already at the 60-hour weekly limit cannot absorb another run without hiring, so a seller showing 15% revenue growth on the same drivers is claiming something the logs should support.