If the trailer brakes work and the pickup manufacturer's limits aren't being exceeded I don't see an issue.
No, it’s not safe. First of all he is videoing while driving, and then speeds back up to continue videoing after being passed. Totally unsafe.
A grain trail manufacturer used to deliver ther trailers like that had air break set up for the ton truck was real slick
If there is an air brake system set up, and it was an empty trailer (or almost empty) it really isn't terrible.
