▁trans bra ke ▁ ▁forces ▁the ▁race ▁car ▁to ▁remain ▁station ary ▁at ▁the ▁starting ▁line , ▁in ▁g ear , ▁regardless ▁of ▁how ▁much ▁engine ▁power ▁is ▁applied . ▁When ▁the ▁visual ▁signal ▁is ▁given ▁to ▁start ▁the ▁race , ▁the ▁driver ▁triggers ▁the ▁delay ▁box ▁to ▁begin ▁timing ▁( pre cis ely ▁counting ▁down ). ▁If ▁the ▁driver ▁does ▁not ▁interrupt ▁this ▁timing ▁device , ▁the ▁car ▁is ▁launched ▁down ▁the ▁race ▁track ▁at ▁the ▁instant ▁the ▁timer ▁exp ires ▁( count s ▁to ▁zero ). ▁Del ay ▁box ▁use ▁was ▁very ▁controvers ial ▁in ▁the ▁ 1 9 8 0 s ▁and ▁ 1 9 9 0 s , ▁as ▁it ▁removed ▁a ▁portion ▁of ▁the ▁advantages ▁more ▁experienced ▁rac ers ▁had . ▁There ▁was ▁a ▁period ▁where ▁techn olog ists ▁added ▁and ▁conce aled ▁hom em ade ▁circuit ry ▁inside ▁a ▁delay ▁box ▁that ▁viol ated ▁some ▁racing ▁associations ▁rules . ▁Racing ▁associations ▁have ▁im posed ▁strict ▁limits ▁on ▁delay ▁boxes ▁today , ▁with ▁manufact ur ers ▁having ▁to ▁submit ▁to ▁an ▁appro val ▁process , ▁which ▁has ▁dr ast ically ▁reduced ▁the ▁number ▁of ▁mak ers ▁of ▁these ▁devices . ▁ ▁Mechan ism ▁The ▁delay ▁box ▁acts ▁as ▁an ▁on - board ▁timer ▁for ▁the ▁transmission ▁bra ke ▁( comm only ▁referred ▁to ▁as ▁a ▁" trans - bra ke "). ▁A ▁trans bra ke ▁is ▁a ▁part ▁of ▁a ▁racing ▁automatic ▁transmission ▁used ▁in ▁drag ▁racing , ▁and ▁are ▁not ▁found ▁in ▁manual ▁transm issions . ▁The