. m . ▁or ▁ 1 2 ▁p . m . ▁Trad itionally , ▁the ▁track ▁clos es ▁at ▁ 6 : 0 0   p . m . ▁ ▁Happy ▁H our : ▁The ▁final ▁hour ▁of ▁practice ▁and ▁qual ifying ▁each ▁day ▁is ▁referred ▁to ▁as ▁" H appy ▁H our ". ▁Due ▁to ▁the ▁large ▁double - deck ▁grand stand s ▁on ▁the ▁front st retch , ▁large ▁sh adows ▁are ▁cast ▁over ▁a ▁good ▁portion ▁of ▁the ▁track , ▁cool ing ▁the ▁as ph alt ▁surface . ▁A ▁lower ▁ambient ▁air ▁temperature , ▁along ▁with ▁a ▁lower ▁track ▁surface ▁temperature , ▁usually ▁transl ates ▁into ▁faster ▁spe eds . ▁Since ▁Indiana ▁began ▁obser ving ▁Day light ▁S aving ▁Time ▁in ▁ 2 0 0 6 , ▁this ▁phenomen on ▁has ▁been ▁somewhat ▁dimin ished . ▁ ▁Fast ▁Friday : ▁The ▁final ▁practice ▁session ▁before ▁pole ▁day ▁qual ifying ▁is ▁nick named ▁" F ast ▁Friday ". ▁The ▁fast est ▁spe eds ▁of ▁the ▁month ▁are ▁commonly ▁observed ▁on ▁Fast ▁Friday , ▁as ▁teams ▁and ▁drivers ▁make ▁their ▁final ▁prepar ations ▁and ▁look ▁for ▁final ▁" b rag ging ▁rights " ▁before ▁the ▁run ▁for ▁the ▁pole ▁position . ▁Since ▁the ▁current ▁engine ▁formula ▁was ▁adopted ▁in ▁ 2 0 1 2 , ▁elev ated ▁tur bo char ger ▁" boost " ▁levels ▁have ▁been ▁permitted ▁on ▁Fast ▁Friday , ▁reflect ing ▁the ▁increased ▁level ▁allowed ▁during ▁time ▁tri als . ▁D ri vers ▁who ▁have ▁been ▁" s and