NAVIGATION SYSTEM AND SERVER APPARATUS

A navigation system includes a server apparatus connected to vehicles via a network and a navigation apparatus connected to the server apparatus via the network. The server apparatus receives, from a first vehicle, traffic-related information related to snow on a road on which the first vehicle has traveled or slipperiness of the road, and location information of the road; generates difficulty information for the road related to a travel difficulty caused by the snow or the slipperiness; and transmits the difficulty information and the location information to the navigation apparatus movable together with a second vehicle identical to or different from the first vehicle. The navigation apparatus receives the difficulty information and the location information; sets a traffic regulation for passage of the second vehicle through the road; and sets, for the second vehicle, a travel route based on the traffic regulation.