General information for carriers. This article is not legal, tax, accounting, or regulatory advice.
A reroute is a business decision, not a reflex to a radar image. Weather, a closure, or a chain restriction changes the miles, the hours, the fuel, and sometimes the appointment you can still make. Sitting is also a decision, with its own cost. Make the call early enough that you still have options, and write down why you chose it. A note from the morning is worth more than a reconstruction after a missed delivery, when everyone is looking for someone to blame. The truck can only be in one place. Pick it on purpose.
Use a small set of sources and a cutoff time. A forecast, a state department of transportation closure page, and a chain-law or mountain-pass report if the lane has one. Check them before the driver is in the weather, not after. Set a decision time: if the route is still ugly at that hour, you reroute, you delay the pickup, or you sit. Endless refreshing is not caution. It is how you lose the window to tell the broker while they can still work the receiver. One check at the cutoff beats five anxious looks that never become a decision.
Compare the cost of the detour with the cost of the delay in numbers you can say out loud. Extra miles, extra fuel, and whether the new ETA still makes the appointment. Against that, the cost of sitting: a missed door, a layover, a relay, or a day the truck does not earn. If the detour is forty miles and saves the appointment, take it and tell the broker the new miles only if you expect to be paid for them. If the detour is half a day and still misses the door, sit or reschedule. Do not spend fuel to arrive late anyway.
Notify the people who can act. The broker needs the new ETA and the reason before their customer hears it from a tracking ping. The driver needs a clear instruction: which road, where to stop if the road closes, and what not to attempt. If you are the driver and the office, write it down anyway. Fatigue and weather are a bad time to trust memory. If a shipper must move a pickup, ask early. A closure you saw at dawn is not an emergency at noon. It became an emergency because the call waited.
Write the reason in the load note the same day. Storm, closure, chain restriction, or a detour you chose to protect the appointment. Include the time you decided and who you told. That note does three jobs. It helps billing if someone later disputes a late fee. It helps the next dispatcher when the same lane does the same thing every winter. And it keeps you honest about whether you decided or drifted. A reroute without a reason is just extra miles. A reroute with a reason is a record you can defend.
Mountain passes, ice, high wind, and flood closures each have a practical limit that should be decided before the driver is at the bottom of the grade. If the lane requires chains and the truck is not set up, that is a no, not a hope that the sign will change. If wind restrictions hit your trailer type, do not park on the shoulder and negotiate with a gust. Stop at the last sensible lot and call. High wind and a light trailer is a known way to spend a deductible. The appointment is not worth that. Reschedule from a parked truck, with the restriction in the message.
After the load delivers, keep the weather note with the file. If a late fee shows up, you already have the time, the source, and who was told. If the same corridor closes every season, the note becomes a planning rule: do not book that pass on a tight window in that month without a layover built in. Weather will happen again. The only waste is paying for the same surprise twice because nobody wrote down the first one.