My informal tests have shown that I'm about 1.5mph slower on my Burley Canto than I am on my road bike. That's a typical difference over the course of a complete ride, in flat-to-rolling terrain. On my TerraTrike I'm actually 3.5 to 4mph slower. As another poster mentioned though, I can definitely ride further in comfort on either of these, so I'm willing to accept the tendency to slip into "tourist" mode.