None of these speeds are read off a gauge and reacted to in the moment. All three are calculated on the ground, before brake release, for that specific takeoff — and by the time the aircraft is rolling, the decision they encode has already been made.
Every takeoff in a transport-category aircraft is bracketed by three calculated speeds — V1, VR, and V2 — and the whole point of calculating them in advance is to remove judgment from a part of the flight where there usually isn't time for any. Each one answers a different question about what the aircraft can safely do at that instant, assuming the worst plausible failure (typically an engine failure) happens right then. Mixing them up, or treating V1 as something a pilot simply "feels" in the moment, is one of the more persistent misunderstandings about how takeoff safety actually works. This explainer covers the sequence of speeds that governs the go/no-go decision itself — a related but distinct question from the airspeed-instrument topic covered in Indicated vs. True Airspeed.