Reefer Trailer Monitoring Guide: Temperature, GPS & Alerts

What is reefer trailer monitoring?

Reefer trailer monitoring (also called reefer telematics) is the continuous tracking of conditions inside a refrigerated trailer — temperature, humidity, door events and GPS location — so dispatch can protect cold chain cargo while it moves.

Unlike checking a thermometer at pickup or delivery, a monitoring system reports conditions throughout the trip and alerts the team when something drifts out of range.

Why fleets invest in reefer monitoring

One rejected load often costs more than years of monitoring. Common failure modes:

• Temperature excursions after a reefer unit fails or setpoints drift
• Doors left open during loading, stops or driver error
• No proof of temperature history when a shipper disputes the load
• Late discovery — problems found only at the receiver dock

Live cold chain visibility lets owners and dispatchers act while the trailer is still on the road, not after the cargo is already spoiled.

Signals that matter on a refrigerated trailer

A useful reefer monitoring stack usually covers:

• Temperature — cargo-area readings and excursion alerts
• Humidity — important for produce and sensitive freight
• Door / light — open-door events that warm the box
• Reefer health — engine status and battery voltage where available
• GPS location — where the trailer was when conditions changed

How a modern reefer monitoring workflow looks

1. Install a telematics unit and wireless cargo sensors on the trailer
2. Define alarm rules for temperature bands, door-open time and device health
3. Route alerts to dispatch (and optionally drivers) by email, SMS or call
4. Keep trip history, maps and temperature logs for claims and audits

That workflow is exactly what Prokobi RTS is built for: signup online, install with a simple 2-wire connection, then monitor from phone or desktop.

What to look for when choosing a system

• Clear live view for dispatch — not a lab dashboard
• Fast alerts on temperature and door events
• Exportable temperature records for shippers and claims
• Install path that owner-operators and small fleets can complete
• Transparent pricing without forcing an enterprise platform bundle

Enterprise telematics suites can be powerful, but many refrigerated fleets mainly need reliable cold chain visibility at a predictable monthly cost.

Getting started with Prokobi RTS

RTS starter hardware is $185, then $25/month with SIM data included. Create an account at rts.prokobi.com, order the kit, connect the VL802 terminal and place the wireless multisensor inside the trailer.

For documentation after the load, see our companion guide on cold chain compliance and temperature records.