I think MXM is mistaken that speed is an emergent property of a vehicle. That's like saying that rolling is an emergent property of wheels. Not at all---it's the highly predictable outcome of applying energy to the system in some way. To regard these things as "emergent" means that almost nothing is not emergent. The essence of emergence is that the mechanisms involved, when acting en masse, exhibit properties that would be difficult or impossible to predict by examining the mechanisms themselves. Very often you see apparently complex behaviors emerging from very simple rules or principles. Murmuration of starlings is a classic. Synchronized motions of fish in a school. There are no global communications involved in these phenomena--the 'emerge' from the almost trivial rules that govern interactions among neighbors. One of the most spectacular examples is Conway's "Game of Life" in which arbitrarily complex behaviors emerge from rules you could write on a 3x5 card with a magic marker.