With no armor, no horns, and much shorter legs than their tyrannosaur predators, hadrosaurs would seem to have been sitting ducks. But I think the secret to the group’s survival may have been their adaptations for endurance. Duckbill vs. tyrannosaur at the dino derby! Place your bets.
Persons WS IV, Currie PJ. 2014. Duckbills on the run: the cursorial abilities of giant Late Cretaceous ornithopods and implications for tyrannosaurs avoidance strategies. In: HADROSAURS (eds. Eberth DA and Evans DC). Indiana University Press, Indianapolis, IN. 449-458.