1935 — Motor Carrier Act , ch. 498, 49 Stat. 546 (renamed part II of the Interstate Commerce Act ) August 14 , 1935 — Social Security Act , including Aid to Dependent Children , Old Age Pension Act, Pub.L. 74-271, ch. 531, 49 Stat. 620, 42 U.S.C. § 301 et seq. August