Switch Island is a major road junction near Aintree in Merseyside, England, in the Metropolitan Borough of Sefton. The junction is at the western terminus of both the M57 and M58 motorways, which converge on the A59 trunk road, the north-south route from Liverpool. The junction is also the terminus of the A5036, a road which serves the Port of Liverpool, and the A5758 which serves as a bypass for the village of Thornton. For the period between the 1930s and mid 1970s, the island was a simple roundabout formation until the arrival of the motorways. The junction was significantly expanded in 1980 and was initially planned to be an interim layout, however subsequent additions and amendments throughout the years, separate to the original intentions, has transformed it from the original roundabout design and then-envisaged grade separated junction. The junction carries up to 100,000 vehicles a day with continued improvements being a priority for Highways England. The through route of the dual carriageway is not the A59 south to the A59 north, but from the A5036 south to the A59 north, effectively resulting in two motorways and the port road feeding onto the A59 through route. Switch Island has been described as one of England’s busiest motorway junctions and is prone to traffic collisions due to its extensive utilisation and inadequate layout. History Original formation The junction originates from the construction of Dunnings Bridge Road during the 1930s, linking what is now known as the A59 to the A5036 (then known as the A567 road). A simple roundabout was constructed sometime during the 1930s - 1940s and remained in this unchanged configuration until construction of the M57 motorway reached the island in 1974. The original island remained virtually unchanged for almost 40 years, until the new motorway joined the road and the original island fell out of use as the layout around it changed to accommodate roads for the motorway junction. A road map from 1975 shows the original island alongside new roads to the east connecting the motorway, despite suggesting it was not functional in its original roundabout configuration. Motorway junctions During phase 2 of the M57 construction in the mid 1970s, the motorway was routed to terminate at the junction, which involved constructing a new link road for the entry and exit sliproads, with the original roundabout becoming largely redundant. The new road connecting the M57 motorway would