With a road bike its best to learn how to pop up the front and rear wheels separately. That way when you come up to a curb you first pop the front wheel up (primarily done by pulling up on the bars and giving it a good kick on one pedal). Then when the back wheel is a few inches from hitting the curb, lean forwards on the bars and use the clipless pedals to "bunny hop" the back wheel over the curb. Make sure that you don't lean to far forwards, especially in deep grass. If I had a dollar or every face plant from this move I've seen going into the grassy areas around crit courses (not people who were racing, but people who already did race or were waiting to race). If you get good at this you should be able to do the back and front wheel at the same time, enabling you to hop over RR tracks at full speed. Make sure they aren't double tracks though, its a LOT farther and you risk landing a wheel on the rails which could either get you hurt badly or at the least you wheel.