Almost every car used to qualify for severe duty. ie mostly city driving, sustained high speed, high or low temps used to qualify as severe duty. Seems only cars driven between 50-80F at 55mph on the Highway used to qualify for the regular interval. My 2004 Focus Owners Manual has the folowing definition of Severe Duty: Towing Heavy Commercial Use Operating in Dusty Conditions Off Road Operations Seems the vast majority of passenger vehicles now qualify for the Regular Service Interval. I assume most Trucks, UVs (Full Size) , and SUVs (Compacts) that are actually used as intended will still be Severe Duty. Of course most SUV owners use them as glorified station wagons and car based SUVs are a different animal entirely. Is this a Ford only change related to the adoption of 5W-20? I would assume meeting WSS-M2C-153H (Group II/III Blend or at least II+ with a robust additive package) would reduce shearing and increase the longevity of th oil over a low-end SL 5W-30. Any thoughts on this?