All field notes
Drawing a polygon around a customer site is easy and nearly useless on its own. The value is in what the crossing triggers, who it tells, and whether the system can tell an arrival from a lorry taking the roundabout outside your gate.
Entry, exit, and dwell are three different events
Entry answers "has it arrived". Exit answers "has it left". Dwell — how long it stayed — is the one that answers the question dispatchers actually ask, which is whether the delivery is running late or whether the driver is still queueing at the gate.
- Entry without dwell tells you a vehicle touched a boundary, which a passing lorry also does.
- Exit without entry tells you nothing at all, and usually means the fence was drawn after the vehicle was already inside it.
- Dwell over a threshold is the event worth waking somebody for.
Off-limits areas are a safety control, not a report
A restricted zone that produces a line in a monthly report is documentation of an incident. The same zone wired to an immediate alert — and, where the fleet policy allows it, a remote ignition cut-off once the vehicle is stationary — is a control.
FMS will not cut ignition on a moving vehicle. The command is queued and applied at the next confirmed stop; a fleet console that can stall a lorry on the Al Ring Road has been designed by somebody who has not driven one.
Draw fewer, better
The fleets that get value from geofencing run a dozen of them. The ones that get noise run two hundred, drawn once during onboarding and never revisited, half of them around sites the company no longer serves.
Every fence is a promise that somebody will act when it fires. Draw as many as you can keep.