The calculation of routes is affected by various factors: 
Actuality of maps, traffic rules, traffic conditions, vehicle type, route type (fast, short and others), route options (highways, ferries and others), personal driving style of the driver, the day of the week and time of day. 

If you have set a route profile 'Best route', up to three alternative routes for the selected route profile are offered after the route calculation. 

The colors of the 3 routes don't mean "scenic", "fast", or "normal" route. The routes are only alternative routes.