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Exits get lost when the gate is left open, security is busy with something else or the driver follows another vehicle out. A dwell time report built on such a register is useless, which is why the fix starts on the exit side, and the report comes afterwards.
Why measure vehicle dwell time
The first reason is settling up with the carrier. Waiting time charges and free time are set by the contract, and the data from the gate is a reference point for both sides. Dwell time also shows bottlenecks: if the average visit is getting longer, something is happening at the docks or in the queue, and you see it before it shows up in complaints.
Then there is security. A vehicle that has been standing on site for twelve hours for no reason needs checking straight away, before it becomes a line in a table that someone notices on Friday. And there is record-keeping: the question of who was on site and for how long usually comes up after an incident, when the record can no longer be filled in.
Dwell time threshold, alert and automatic visit closure
The time threshold defines how many hours still count as a normal visit. Thresholds need to differ by entry type, because a delivery with unloading takes a different amount of time from a visit by service engineers who work on site all day.
Exceeding the threshold can trigger a signal on the dashboard, an alert for security or an email to the dispatcher. The most common mistake is an alert set for everything: after a week nobody looks at it any more, so it should cover the exceptions only.
Then there is automatic visit closure. Without it, the register fills up with open visits from weeks ago and stops meaning anything. In TraxSystem you set it as a threshold in minutes, and a value of 0 switches the mechanism off. The entry and exit log, dwell time included, is part of the base system and needs no additional module; base prices for one, two and five gates are on the pricing page.
What automatic visit closure means
The automatic mechanism closes visits that have exceeded the threshold, because the vehicle most probably left long ago without its exit being registered. Without it, the ‘on site’ list would grow indefinitely.
The automatic closure does not record that the vehicle left at a particular time; it closes a record that nobody closed. It tidies the register rather than measuring anything, so only visits with a real exit event are fit for settling up with carriers. The two kinds of visit have to be kept apart in the report: visits closed by an event are data, while visits closed automatically are information about a gap in exit registration.
How to reduce unregistered exits
An ANPR camera on the exit side closes the visit with nobody involved: recognising the number plate is all it needs, so you do not have to rely on anyone’s discipline. The camera is hardware and is priced separately, outside the licence. A separate exit lane instead of one gate used in both directions also helps, because the direction then follows from the point the vehicle passes through. If vehicles receive a card on entry, returning the card on exit works well too.
The direction of passage should follow from the type of point, not from interpreting the event. The quality of every dwell time report depends on that distinction.
What dwell time control does not cover
TraxSystem will not detect an exit that was not registered. If a vehicle left through an open gate with no camera and nobody on duty, the system will not find out and will close the visit automatically once the threshold has passed. Dwell time control does not locate the vehicle on site either: it knows that the vehicle came in and has not left, but not which dock it is standing at.
Exceeding the threshold triggers a signal and does not block the exit. Nor is the visit register a billing tool in the legal sense: the data from the gate is a record of events, and how waiting time is charged is set by the contract with the carrier.
Questions and answers
Can dwell time be measured without cameras?
Yes, with manual registration at the gate. The quality of the data then depends on how consistently exits are registered, which is usually the weak point.
Where can we see vehicle dwell time data?
In the reports, filtered by period and scope. Reports are limited by what each user is allowed to see, so two people may see different figures, and that is intentional.
What about vehicles that stay overnight?
You set a higher threshold for them or a separate entry type, so that a planned overnight stay does not trigger an alert meant for exceptions.
See also: How many people are on site right now · Truck queues at the gate: where they come from and how to clear them · Random vehicle checks: how they work and what they are for · What is ANPR: number plate recognition explained