Road type network
The higher the road type, the more important it is to connect them within a network. Waze should be able to route from primary to primary (or higher type), from minor to minor (or higher), from Major to Major (or higher), and from Freeway to Freeway. Another way of explaining this, is that you should be able to continuously drive on the same or higher type of segments for the routing engine to use that road type in the calculations. This means we sometimes need to make small roads a higher road type than they are in real, to create a good network of Waze road type segments.