I tried the different route option settings today. Shortest and fastest gave me distinctly different routes. But I am not sure about 3, it gave me the same route as fastest, when the traffic on the route was red.

I also experimented with adding this route option to AppSettingsModel and exposed it to setting menu. But unsurprisingly, only pre-defined variables (in settingManager) are allowed so I couldn't use the set method to store the route option. I then added it as a property to AppSettingsModel, but like the comments in the code suggested, property in this QtObject is not reliable and I couldn't change the property either.