Disclosed are techniques for vehicle feature assumption evaluation. In an aspect, an assumption associated a vehicle feature defines (i) at least one response by an attentive driver to at least one in-vehicle human-machine communications interface stimulus, (ii) timing information associated with at least one in-vehicle driver action, or (iii) a combination thereof. Behavior of attentive driver(s) is monitored, and used to calculate a confidence level associated with the assumption being valid based on the monitoring.