Routing and route optimisation

A routing engine treats roads as a graph with speeds, turn rules and, from some providers, live traffic, and finds the quickest path for driving, cycling or walking. A distance matrix returns travel times between many starting points and destinations at once, which is how an app finds the nearest driver or store. An isochrone shows everywhere reachable within a set time, such as 20 minutes.

Route optimisation is a harder problem: given 40 deliveries, 3 vans, time windows and vehicle capacities, find the order and split that minimises driving. It is known as the vehicle routing problem, a relative of the travelling salesman problem. Google's Route Optimization API and Mapbox's Optimization API solve it as a service billed by usage, while OSRM, GraphHopper, Valhalla and VROOM are open-source engines that run on OpenStreetMap data on your own servers.