Complex sentence: The support vehicle serves two purposes: to haul the luggage of the tour participants and spare bikes, as well as water and snacks; and to provide shelter for passengers or riders who have fallen ill during the trip.
Split into simpler sentences: The support vehicle serves two purposes, to haul the luggage of the tour participants, the spare bikes as well as water and snacks. The secondary purpose is to provide shelter for passengers or riders who have fallen ill during the trip.