The general provisions for the final exportation of road vehicles are to be found in fact sheet 15.51, export of road vehicles and trailers from the customs area (PDF, 42 kB, 19.12.2014)
Export: cf. fact sheet 15.51 section 1.
Special cases: cf. fact sheet 15.51 section 2.
Registration documents, number plates: cf. fact sheet 15.51 section 3.
Travellers domiciled in Switzerland can export vehicles from Switzerland for their own personal use without declaring them.