Yeah, the maximum momentum of an ant is less than the speed at which suddenly stopping (i.e. impact with any other object) causes damage. An ant probably doesn'

Yeah, the maximum momentum of an ant is less than the speed at which suddenly stopping (i.e. impact with any other object) causes damage. An ant probably doesn't even have minor injuries in its normal operation, including any impacts with other ants or objects. Also, pedestrians and cyclists and motorcyclists aren't ants. Some other metaphor would apply to them, and they can be damaged by the "ant" (a car) a lot easier. But I think the most important difference is ants are cooperative rather than competitive; ants don't get pissed, whereas primates seem to require becoming irate occasionally even for no good reason.