Detention & Demurrage Management

Detention and demurrage are fees charged when equipment — a trailer, chassis, or container — is held beyond an agreed free time, and they represent one of the most direct, invoice-visible costs of yard inefficiency. A YMS gives operations teams the timestamped data needed to avoid these charges in the first place, and to dispute them accurately when they occur anyway.

The two terms are often used loosely but describe different situations. Detention typically refers to charges a shipper or receiver pays a trucking carrier for holding the carrier's tractor or trailer beyond the free loading/unloading time allotted at a facility. Demurrage typically refers to charges a shipping line or rail carrier assesses for holding a container beyond its free time at a port, rail ramp, or terminal — before it even reaches the yard, or after it needs to be returned. Both are essentially rent charged on equipment that isn't moving.

• Detention — trucking carrier's equipment held too long at a facility
• Demurrage — ocean/rail carrier's container held too long at port/terminal
• Per diem — a related term, often used for container/chassis daily use fees once removed from the terminal

Most carrier and terminal contracts define a free time window — commonly 1-4 hours for trucking detention, and 2-5 days for ocean demurrage — before charges start accruing, typically on an hourly or daily basis after that. The clock generally starts at gate-in or at unloading of the vessel/rail car, and stops at gate-out or empty return. Because these clocks run continuously regardless of business hours, a trailer that arrives Friday evening and isn't touched until Monday morning can accumulate a significant charge purely from a scheduling gap.

The most effective way to manage detention cost is to never incur it — which means keeping dwell time inside the free window through better scheduling and prioritization. A YMS supports this by surfacing a live countdown or alert as a trailer approaches its free-time limit, letting supervisors reprioritize labor to unload or reload it before charges begin. Some systems integrate this alerting directly into the dock scheduling and task management modules, automatically escalating a trailer's move priority as its clock runs down.

When charges do occur, carriers and terminals send invoices based on their own records, which don't always match the facility's actual experience — a carrier might claim a trailer arrived at 8:00 AM when the gate log shows 10:30 AM. Because a YMS records precise, timestamped gate-in and gate-out events independently of the carrier's system, it becomes the primary evidence for disputing incorrect or inflated detention and demurrage invoices. Facilities without this record are effectively negotiating blind and often pay charges they could have contested.

Beyond individual disputes, aggregated detention data reveals patterns — certain carriers or lanes consistently generate more detention than others, which is valuable leverage in rate negotiations or carrier scorecard reviews. A facility that can show a specific carrier "your drivers account for 60% of our detention hours despite being only 20% of our volume" has a much stronger negotiating position than one relying on anecdote.