A navigation system includes primary and secondary navigation device, and a server. The secondary navigation device transmits geolocation data to the server. The primary navigation device receives user input indicating a destination. The primary navigation device also determines a current route to the destination based on a current location of the primary navigation device, and transmits the current route to the server. The primary navigation device also receives and displays a difficulty index from the server in response to transmitting the current route. The server determines historical routes reflecting historical commutes based on the geolocation data. The server also determines the difficulty index based on the one or more historical routes and the current route, and transmits the difficulty index to the primary navigation device in response to receiving the current route.