Avg speed on road -vs- trainer?

This can be tricky depending on where you ride outdoors. It might be common to have a fatser average when on a trainer but remember that you NEVER have to slow down for corners, turn-arounds, traffic, intersections, ect. I'd guess that if you were able to subtract the effect of all those things most people would probably average a faster outdoors. You might want to compare a short-term average on each. For example, take your average speed on a nice long section of road without any obstructions...maybe 3-5 miles if you can find something like that. Then compare that to a 5-10 min average on the trainer at a decent workout pace (no hills or sprinting unless that is also what you had on the road section). I'd bet that the constant resistance on the trainer will probably result in a slower average. I sure know that 90min on my trainer is a tougher workout then 90min outside on my bike.

There is no doubt that my average speed on a stationary bike is much higher (30 mph+) than on the road (15mph). Although, I must point out that there are three stationaries at the gym and they give me different averages, ranging between 20mph and 30'some mph. The reason my average is lower on the road is because I am commuting most of the time and there are traffic lights, stop signs, hills, debris, wind, rain and potholes that all conspire to slow me down. There are no dogs to chase me, not children darting in front of me, no little furry animals scurrying across my path. There are also no motor vehicles, no cyclists, no roller-blader, no skate-boarder and no pedestrians cutting me off. But still ... I prefer riding on the road!