Face it most drunk driving arrests (DUI) are made between midnight and 4:00 A.M. Los Angeles DUI lawyer Lawrence Taylor  posted about the effects of the your circadian rhythm  and the field sobriety tests .  Your circadian rhythm is basically your body clock. It stands to reason that if your are doing a agility test  late at night , your body might not perform as well . it is common knowledge that west coast or east coast football teams don’t play as well when they travel to the opposite coast.

British physicians and psychiatrists reported that "the same blood alcohol level is associated with a significantly greater impairment of different aspects of psychological functioning when achieved in the morning." "Circadian Variation in Effects of Ethanol in Man", 18 (Supp. 1) Pharmacology, Biochemistry and Behavior 555.



It stands to reason that there are more factors that impact the field sobriety tests than just a beer or two.