▁Iowa - Ill inois ▁Memorial ▁Bridge , ▁and ▁often ▁called ▁The ▁T win ▁Br id ges , ▁or ▁the ▁I - 7 4 ▁Bridge , ▁is ▁a ▁pair ▁of ▁susp ension ▁brid ges ▁that ▁carry ▁Inter state ▁ 7 4 ▁across ▁the ▁Mississippi ▁River ▁and ▁connect ▁B ett endorf , ▁Iowa ▁and ▁Mol ine , ▁Illinois . ▁It ▁is ▁located ▁near ▁the ▁ge ographic ▁center ▁of ▁the ▁Qu ad ▁C ities . ▁ ▁The ▁bridge ▁was ▁designed ▁by ▁engineer ▁Ralph ▁Mod jes ki . ▁ ▁The ▁first ▁span ▁opened ▁in ▁ 1 9 3 5 ▁as ▁a ▁to ll ▁bridge . ▁ ▁In ▁ 1 9 6 1 , ▁an ▁identical ▁tw in ▁span , ▁built ▁from ▁the ▁same ▁blue print , ▁opened ▁to ▁facil itate ▁increased ▁traffic ▁dem ands . ▁ ▁T oll s ▁were ▁dis cont in ued ▁in ▁ 1 9 7 0 . ▁The ▁tw in ▁sp ans ▁were ▁merged ▁with ▁Inter state ▁ 7 4 ▁in ▁ 1 9 7 5 . ▁ ▁Bu ilt ▁for ▁a ▁daily ▁crossing ▁of ▁ 4 8 , 0 0 0 ▁vehicles , ▁the ▁daily ▁average ▁is ▁ 8 0 , 0 0 0 , ▁making ▁it ▁by ▁far ▁the ▁most ▁tra ve led ▁bridge ▁in ▁the ▁Qu ad ▁C ities . ▁Both ▁the ▁Inter state ▁ 8 0 ▁and ▁ 2 8 0 ▁brid ges ▁are ▁up ▁to ▁Inter state ▁standards , ▁while ▁the ▁Inter state ▁ 7 4 ▁Bridge ▁is ▁function ally ▁ob sole te ▁and ▁was ▁not ▁built ▁to