During the mid-1960s, small sections of the route between Plymouth and Exeter were upgraded to dual carriageway, such as those at Dean Prior and Heathfield. This was followed by the construction of Plympton bypass in 1970–71, with the majority of realignment, such as the Ivybridge and Buckfastleigh bypasses, being completed during 1973–74. The route, now known as the Devon Expressway, was largely complete by 1975, with the final section between Kennford and the M5 opening in 1977, coinciding with the completion of the M5 during the same year. Whilst many of the sections were newly constructed realignments, some sections such as the Ashburton and Kennford bypasses were upgraded from the original 1930s single carriageway bypasses. The Parkway, the section of dual carriageway through the suburbs of Plymouth between the Tamar Bridge and Marsh Mills, was constructed in 1983–84, along a route which had been reserved for this road since 1943. This was followed by the construction of a flyover over Marsh Mills roundabout in 1992, providing a non-stop route between the Plympton bypass and the Parkway.