Purely quantum phenomena such as dynamical localization (DL) can be observed in a molecular rotor subjected to a periodic train of short and intense laser pulses in the gas phase. Using requantized Classical Molecular Dynamics Simulations, we investigate the impact of collisional effects for O2 molecules. We consider different trains of kicks for which the system exhibits quantum resonance, DL, or Bloch oscillations under collision-free conditions. Within achievable experimental conditions, we demonstrate that, as the gas pressure increases, all the dynamics become progressively similar, leading to a quantum-to-classical transition. We study how decoherence induced by intermolecular collisions reduces the quantum interferences through loss of memory. These findings pave the way for future experimental investigations and further theoretical studies on the influence of dissipation on quantum effects in rotational dynamics.