The source I can see is the VD geoportal [1], but it concerns only the cantonal roads...

Best regards,

Rémi

[1] http://www.geo.vd.ch/theme/mobilite_thm?map_x=534790&map_y=154560&map_zoom=7&tree_group_layers_mob_donnees_routieres_grp=dgmr_rc_classif&tree_groups=mob_donnees_routieres_grp&featuregrid-container_collapsed=true