Often on the road I see pickup trucks and small trailers being used to haul unsecured items. Please take the time to secure whatever you are carrying with some bungee cords. I know people think that their items are too heavy to blow in the wind. I hope this story will change your mind.
My dad owns a business and needs to haul items ranging from a few ounces to a few hundred pounds all the time. He's owned his business for over 20 years, so you can imagine how much he has transported in that time. A few years back he needed to move a large, heavy recliner from one house to another. It must have weighed fifty pounds. He put it in the bed of his truck. He didn't bother to secure it because he figured that even if it did move, it would just slide around a bit against the walls of the truck. I'm sure you can see where the story is going. He hit 55 on the highway, the wind caught the recliner, and it went flying out of the truck like a ball tossed by a little kid. Fortunately, he lives in a rural area and the highways never have heavy traffic. There could have been a tragedy that day. Instead the recliner landed on the side of the road and busted all to pieces.
I have a second story to show how dangerous even a small item flying from a car or truck can be. When I still lived at home, my mom and I ran rescue squad. I was an EMT-Basic and she eventually made it to EMT-Cardiac Tech. The rescue squads in our area are volunteer organizations and it's common for people to drive their personal vehicles to calls that need extra help. There was a tragic car wreck one day that took the time and effort of many EMTs and firefighters. My mom was there that day doing her part.
While there she and a lot of other people noticed a truck parked on the side of the road several yards down from the crash. No one paid much attention; everyone there just assumed it belonged to someone on scene. After all the injured people were packaged and sent away in ambulances someone noticed that the truck was still sitting in place. That's when a group finally decided to investigate the truck, only to find a very sad sight. The windshield had been shattered by a piece that had flown off during the wreck, and the driver had been impaled through the chest. Amazingly, he didn't die instantly. He was able to steer his truck to the edge of the road, park, and turn it off. There's no way to know if he might have lived if anyone had known to check his truck. The point is valid either way, projectiles from moving vehicles can be very deadly. So please, secure your load when you're on the road.