Brian Gootee, Gray Goat Sports explains the difference between a road bike and a triathlon bike.
A triathlon bike has a shorter top bar and a shallower seat angle. These difference make the rider feel like he or she is sitting a bit lower and further back on the bike. The front section of the frame is longer, which gives the rider more room to stretch out to the aero bars.
A road bike has a longer top bar and more sharply angled seat, which gives the rider more room to move his or her legs freely. The shorter front section of a roadbike allows a rider to support his or her body weight without having to lean into the handlebars.