UPS' ORION (On-Road Integrated Optimization and Navigation) platform uses advanced algorithms, artificial intelligence and machine learning. It includes detailed turn-by-turn directions to guide drivers, not just to addresses, but to specific package drop-off and pickup locations like loading docks that are not visible from the street.
It saves UPS about 100 million miles and 10 million gallons of fuel per year. The latest generation also recalculates individual package delivery routes throughout the day as traffic conditions, pickup commitments and delivery orders change.
My guess is that it is very efficient.