Trunk Mounted Bicycle Carriers are most commonly offered in 2 and 3 bike capacities. This style of rack is more economical compared to the more expensize hitch mounted racks. Loading bicycles on a rear mounted rack is much easier that lifting them onto your car roof rack. Plus, when you're finished using the rack simply loosen the straps, remove the rack and stow it away for the next ride. Strap on bike racks are ideal for the occasional user. However, if you plan to transport your bike often we may reccomend spending some extra cash on a hitch mounted rack if that is an option on your vehicle. Trunk mounted racks in most scenarios prevent access to the trunk while the rack is mounted to the vehicle which if you use it often will interfere with accessing the available cargo space in your vehicle.