I have checked my average speeds on my Phillip's folder in urban riding conditions and it actually performs better than many of my full sized bikes... it only has a top speed of 45kmh and cruises very nicely in the high 20's and have been averaging nearly 20kmh over some extended riding.

It is a heavier bike (touring set up) but the drop bars offer better aerodynamics and those small wheels spin up very fast... have thought of trying a fairing and we have one at our shop I could test.