When the engine is cold, the Intake Air Bypass Control Thermal Valve sends air to the injectors. (Bypassing the throttle.) It's regulated by engine coolant temperature. Once it's hot enough, it closes.
Because of the added air, the engine will require more fuel AND the idle will be higher. How much higher varies. Honda doesn't spec cold idle speed (only hot idle speed) as far as I can tell.
What RPM is your cold idle when you are in neutral? I don't have an R18, so if several of you report that, than you'll know what "typical" is. If you are outside of "typical" (or even high typical) consider having a mechanic take a quick look. (It means dropping your car off the night before so they can see your cold idle behavior.)
But if you *are* in the typical range, DO NOT "warm up" your car in the driveway. During cold idle you're burning well over a liter of fuel an hour for no good reason. (You get ZERO MPG!) Just drive, that's the best, most fuel efficient method of warming up your engine. The only exception is safety related - on some humid days you want just enough coolant temperature to be able to operate the defroster efficiently. But otherwise you are just burning over a liter of fuel an hour for no good reason.
(OK, the other exception is extreme cold, but a block heater and a grille block is the far better solution there.)
OH, the guy down in texas whose car smells like a gas station? That's not normal. The engine only operates open loop for a *VERY* short amount of time (seconds, not minutes). Closed loop is an efficient burn. It'll take a while for the cat to get up to efficient operating temperature, but on the R18 that happens very quickly as well. The cat will be working well long before the IABCTV closes.
-mr. bill