A subcontractor might be delayed. It could rain. So you might pay for a load of cement you can't use, or pay an idle crew while you wait for the truck to arrive. Cemex solved the problem by relying on the brains of its workers. It takes orders only one hour ahead of time.
Cement trucks cruise like cabs, covering the parts of town in which they're likely to be needed.
When a call comes in, the dispatcher assigns it to the closest truck, then the driver decides whether or not he can make the deadline. If he can't, he uses his own experience to identify on the onboard screen which of the other trucks can make the delivery in time. Management stays out of it. Cemex is now the third-largest cement company in the world. At a tactical level, chaos rules - and delivers on time.