Just make sure its completely shut and locked. I've had mine at 75/79mph on the open road on the back of my truck with no problems and that's up high in the direct air stream. One item of my concern for me wasn't the windshield, but the front of the roof as the windshield does direct air up and under the forward edge and lifting the roof hard against the two front roof mounts will be..well drastically increased. I have bar clamps inside with bolts that go through for my light bar and some larger stainless steel washers on the mount points plus the "widows peak" is cut off, but you might want to think about that if you travel long distances at or above 70mph.