Some people pull anything without one, as was stated above. I have only been able to pull trailers for the last 40 years or so. When I started, we pulled with a car. It had a much lower center of gravity, a much wider stance and was heavy. We pulled along US highways, probably 50-60 mph. Only remember the occasional sway. Then came Interstates and pickup trucks. Now we tow faster with a longer trailer. I use two friction bars on mine. Not only is it a better tow when everything is calm, but who hasn't been passed by an 80mph truck or bus? The occasional surprise side wind? The little thunder storm that seems to come from nowhere packing 40mph gusts? Even when you have to make an emergency dodge the debris on the highway move, the trailer will behave much better. I don't tow without them.