I don't use a trailer, but have three kids on the back of my longtail Mundo. I tend to stick to residential streets or roads with bike lanes in them. I'm still a bit skittish riding with the kids on roads with a bike lane where cars are traveling 40 or so, I can't imagine doing so on a road w/o bike lanes. And that's with them physically being on a bike that I can lay down on the curb if I see someone in my rear view mirror coming too close; I imagine I would be even more apprehensive with a trailer.