It's something that automatically controls the rpm of the engine, like a software program that you program into a ECU to keep the rpms within a certaing range allowing you to concentrate on just steering and braking. Every modern car has a rev limiter that's programmed into the ECU. You could modify the program to change it to a higher or lower rpm. For example you could limit the rpm to say 5000 and just keep your gas foot floored throught the whole process preventing the need to change gears. So basically all you need to do is floor the gas pedal and use your left foot to brake while keeping your right foot floored.
I miss that kind of attitiude SOOOO much here in Germany. Here, you could think that someone let sedatives rain during the rush hour (you know, all those a#*holes driving 80 kmh in the left lane and producing stalls etc.)