 Construction of a 5 @.@ 4 @-@ mile ( 8 @.@ 7 km ) long section of Route 4 from what is now exit 6 in East Greenwich to I @-@ 95 in Warwick began in 1967 and was completed in 1972 . That year , the 3 @-@ mile ( 4 @.@ 8 km ) arterial south of the modern exit 5 was also designated as part of Route 4 . The divided highway remains largely intact to this date as the stretch of Route 4 from US 1 to Routes 2 and 102 at exit 5 ; the only piece of the arterial that has been significantly altered is the construction of a bridge over Amtrak 's Northeast Corridor line . By the early 1970s , Route 4 was complete north of exit 6 and south of what would become exit 5 , but there was a still a missing piece in the highway between the two exits . In the 1970s , the state of Rhode Island faced several budget problems and environmental concerns , both of which delayed the construction of the missing link for nearly eleven years . Environmental studies on the missing link began in 1977 , and the state estimated that the 1 @.@ 5 @-@ mile ( 2 @.@ 4 km ) long section of freeway would cost $ 15 – 21 million ( equivalent to $ 59 – 82 million in 2016 ) to construct . 
