Used this car top carrier for a cross country trip of over 2000 miles. We went through every kind of weather including high swirling winds coming at us from every direction as the mountain highway twisted and turned, along with heavy rain, some snow and ice, and traveling at speeds in excess of 75 mph for long stretches of highway. This JEGS car top carrier handled it all with no problem, and at our destination, it was still exactly where it was at the beginning -- no shifting in any direction on the cargo rails -- no tie-downs required at all. The only tie-downs I used were to strap a step ladder to the vehicle - as shown, which had nothing to do with the carrier. I used a dense insulation foam (1 inch x 1 inch in size) on the inside on the mounting brackets. I pierced slit-holes in the foam to fit the spacing of the mounting brackets and slid it down over the bracket poles between the inside of the floor of the carrier and the lock-down plate and then tightened down the thumb screws until they were tight and that stopped any leakage into the interior of the carrier from the mounting bracket holes. At the end of the trip, the carrier was perfectly dry inside. We didn't access the interior of the carrier during the trip and the locking mechanisms worked perfectly - held the top secured tightly and showed no signs of shifting at high speeds during the trip (checked it each time we stopped for gas and to stay at a motel) and they were perfectly in place and tight all during the trip and at the end of the trip. --- I can't see how the locking mechanisms could fail unless they were not installed properly or were somehow defective (which would be obvious) from the start - as others have reported losing the top of the carrier at highway speeds. - Quite literally - I don't see how that's possible unless it wasn't locked down properly before taking to the road. -- Also: The locking mechanisms each have a hole to insert a padlock to prevent anyone breaking into the carrier. We used a padlock on each locking mechanism, but even without the padlock, there should be no way for the locking mechanism to come undone. The only flaw I noticed was the bars for holding the carrier open were very difficult to get put in place and did not sufficiently hold the top up far enough from the bottom for easy loading and unloading, and should be made like the brace of a fold-out ladder with a hinge in the middle of two bars that expand out to hold the top of the carrier up high enough for easy access of the interior. Those bars could be made to be easily installed by the user if properly designed and manufactured so the carrier could still be shipped with the top and bottom nestled together. So - if you're going to take a trip and need extra room for your stuff, this car top carrier would be an excellent choice. It's about half the price of the "top name" brands, but every bit as good at the job as those expensive ones -- and holds a lot more stuff than most of the expensive ones. Overall: I highly recommend the 18 cubic foot JEGS Rooftop Cargo Carrier. It's well worth the investment.