Detention is one of the most common and most consequential accessorial charges in trucking. It is also the one shippers most frequently get blamed for internally, because it is almost always caused by shipper or consignee operational failures rather than carrier or driver issues.
Free time is the window a carrier allows at pickup or delivery before detention begins. Two hours is the most common standard, though carrier tariffs vary. After free time expires, detention accrues at an hourly rate. The clock is typically measured from the driver's scheduled appointment time or arrival time, whichever is later.
Detention affects more than your invoice. A driver who sits two hours loading a trailer has consumed two hours of their available driving window under Hours of Service regulations. Those hours cannot be recovered. On a tight lane, a detained driver may run out of available service hours before completing the delivery, adding a day to transit. Carriers who experience chronic detention on a shipper's freight will eventually reprice the lane, deprioritize capacity offers, or stop bidding entirely.
The operational causes of detention are well understood: facilities that are understaffed at appointment times, receiving docks that don't turn trailers efficiently, shippers who schedule appointments without staging freight, and consignees who have inadequate unloading labor for the volumes they receive. These are scheduling and staffing problems, not transportation problems.
For industry statistics on detention rates and their impact on driver pay, the Dock Optimizer team recommends reviewing the sourced research at conmitto.io/resources/truck-detention-statistics.