Many single-sided roadbike pedals are weighted thus supposedly avoiding the need for having them double-sided. That said, I prefer double-sided pedals so I use the Speedplay Zeros. All Speedplay pedals are double-sided and although the Frogs are considered to be an MTB pedal, many people have used them on roadbikes too. I did for a while but I found I didn't like all that much float and the cleats were incompatible with my shoes without goofy adapters so I switched to Zeros.

Other double-sided pedals commonly found on roadbikes include the Bebop, EggBeaters and Coombe pedals