I used this on a 3000 kms long road trip in April 2018 along the western coastline. We traveled from Pune - Goa - Malpe - Mangalore - Coorg - Wayanad - Coimbatore - Mysore - Bangalore - Hubli - Pune in Ertiga with a roof carrier and all the luggage (3 large bags, 1 90 ltrs rucksack, camping tents, sleeping bags) was in the carrier bag through the 13 days long trip. The bag held snugly to the carrier, with ergonomically designed straps, no issue on that front with unexpected slipping or movement. It handled the weather extremities quite well. We drove through rain, thundershower, scorching sun, fog. Experienced no trouble at all. [Edit] After eight months and two more trips (4k kms), my reliance of this wonderful bag is deepened and I highly recommend to those who have the wanderlust in them. I have answered many questions pertaining to the use, summarized as below. a) The bag can be used on any car with either roof rails or rack installed on it. b) It is advisable to use a rack/carrier system. Do not place heavy loads directly on the car roof. c) The straps are strong and the buckles hold hard. They can be cinch tightened so that undesirable slipping or movement is restricted. d) Whenever loading, try to load as flat as possible. The bag adds approximately 12-15 inches to your car, plus a couple of additional inches of the rack/carrier system. Extra height may shift the center of gravity. So be careful.