Why Google Maps isn't a truck route planner

Google Maps will give you the fastest way from A to B, and if you add stops, it will even reorder them for you. For a single driver running a handful of errands, that's plenty. It falls apart the moment you're planning for a fleet, because Maps has no concept of what's in the truck.

A truck route planner has to know each stop's demand and weigh it against remaining capacity, decide which of several trucks should take which stop, respect delivery time windows that conflict with each other, and route every truck back to the depot at the end, not just to its last stop. None of that is a routing problem in the turn-by-turn-directions sense. It's an assignment problem wrapped around a routing problem, and consumer mapping tools were never built to solve the assignment half.

This is also why manually splitting a delivery list across a few Google Maps links doesn't scale past the first few trucks: someone still has to decide by hand which orders go on which truck, and that decision is exactly where capacity gets miscounted and time windows get missed. Logistics route optimization software exists specifically to make that assignment decision algorithmically, before anyone opens a map.