I've herd its the other way around. Cars that are driven short trips where the motor isn't allowed to heat up to operating temp causes a condition where contaminants and water (condensation) isn't burned off...leading to engine wear from a buildup of impurities in the oil. Engineering stand point: There is minimal metal to metal contact (bearings/ring-wall clearence) at high speed ( 60-90mph)...as compared to heavy stop and go traffic.l Isn't that what Castrol states represents a "Drive Hard" condition---stop and go traffic...not cruizing at high speeds. The oils film strenght is supposed to coat engine parts during this damaging stop and go traffic--thus prolonging engine life. In theory anyways.

 

They claim that engine oil should be changed every 3000 miles. Change it earlier under extreme driving conditions. Stop and go driving is extreme driving conditions. Short trips that don't allow the engine to heat up is just as bad for an engine and oil.