For an upcoming holiday, I wanted to know the best route from Lausanne to Carcassonne. There's an interesting part of the route, where I could decide wich way to go. So, to the INTERNETS....

The interesting part is a diamond of motorways, in the area of Chambéry, Voiron and Grenoble, the A 41, A43, A 48 and A49

I narrowed the problem down by using starting- and end-points near auto-route-exists.
Start: "Allee des cortis, annecy" or "Impasse des Crêts, Cran-Gevrier, Haute-Savoie, Rhône-Alpes, 74960, France", depending on which map knows which point
End: Avenue de Marseille, Valence, France (Sometimes with house-number 1)

Google-Maps: Gives you three options. Two go off the motorway, one stays on it.
Going of the motorway in the Alps isn't a good idea. I will take you longer, nearly every time. So, choosing the one route, where you stay on the motorway, Google take the southern route, through downtown Grenoble. 201km, 2h 18m

Bing-Maps: Takes the northern approach, 212km, 1h 57m

Navteq (via Map24): Same route as Bing, 212km, 2h 13m

OSRM: Southern route, 203km, 1h 52m

Openrouteservice: Same as Google-Maps default route, going of the motorway. 186km, 1h 52m
By manually telling it to avoid the region inside the diamond, the southern approach was used.202km, 1h 53m

Yours: Didn't want to go on the motorway first. After that, same route as Openrouteservice, 188km , no time given

Open.MapQuest.co.uk: MapQuest didn't like me. I had a terrible hard time setting start and end positions. It always ignored the city in my searches and gave me two possibilities, where I had to choose from.
"Allee de Chaffit, Valence, Rhône-Alpes 26000" as endpoint finally worked, giving me 3 options to choose from. First one, the Google-Maps/Openrouteservice-variant, second one using event less motorway, third one completely without motorway.

MapQuest.de: Northern route, 215km, 2h 2m (Again, MapQuest didn't like the addresses. It started in Annecy centre instead.)

Falk: Northern route, 212km, 1h 56m

Via Michelin: Northern route, 214km, 2h (Started in Annecy center instead)

Conclusion:
I'm taking the northern route, using the motorway should be faster, than going off it, even though we would save some kilometres.