▁Id aho ▁Spr ings ▁to ▁the ▁j unction ▁where ▁US   6 ▁currently ▁separ ates ▁from ▁I - 7 0 ▁west ▁of ▁the ▁city . ▁The ▁majority ▁of ▁the ▁alignment ▁through ▁Den ver ▁was ▁completed ▁by ▁ 1 9 6 4 . ▁The ▁M ous et rap ▁re used ▁some ▁structures ▁that ▁were ▁built ▁in ▁ 1 9 5 1 , ▁before ▁the ▁formation ▁of ▁the ▁Inter state ▁Highway ▁system . ▁The ▁last ▁piece ▁east ▁of ▁Den ver ▁opened ▁to ▁traffic ▁in ▁ 1 9 7 7 . ▁ ▁Eisen h ower ▁T unnel ▁ ▁Pl anning ▁on ▁how ▁to ▁route ▁the ▁fre ew ay ▁over ▁the ▁Rock y ▁Mountains ▁began ▁in ▁the ▁early ▁ 1 9 6 0 s . ▁The ▁US   6 ▁cor rid or ▁cross es ▁two ▁passes : ▁Lov eland ▁Pass , ▁at ▁an ▁elev ation ▁of ▁ ▁and ▁V ail ▁Pass , ▁at ▁. ▁Engine ers ▁recommended ▁t unn eling ▁under ▁Lov eland ▁Pass ▁to ▁by pass ▁the ▁ste ep ▁gr ades ▁and ▁hair pin ▁curves ▁required ▁to ▁navigate ▁US   6 . ▁The ▁project ▁was ▁originally ▁called ▁the ▁Stra ight ▁Creek ▁T unnel , ▁after ▁the ▁water way ▁that ▁runs ▁along ▁the ▁western ▁approach . ▁The ▁tunnel ▁was ▁later ▁renamed ▁the ▁Eisen h ower – John son ▁Memorial ▁T unnel , ▁after ▁U . S . ▁President ▁D w ight ▁D . ▁Eisen h ower ▁and ▁Colorado ▁Governor ▁Ed win ▁C . ▁Johnson . ▁ ▁Const ruction ▁on ▁the ▁first ▁bore ▁of ▁the ▁tunnel ▁was ▁started