All colonists move much, much faster than any regular ship, army, oxcart or balloon, because the colonists are so anxious to get out of the Mother Country before the authorities catch up to them...
I'm speaking only of my own family history, of course, but this theory was also the basis for Herr Doktor Professor Werchtensnitzelbaum's famous thesis that America Was Settled Entirely By Riff-Raff, now taught extensively in universities all over the civilized world and in Canada.