The Port Roundabout in St Helier doesn't seem to have an official name of any sort, but this is one of the more common names used for it. It is unique in the channel islands in that it is a full Grade Separated Junction on a dual carriageway. The dualled A1 free-flows underneath the roundabout, in an excavated trench, the base of which could well be below high tide level. Whilst the underpass is a functional concrete lined channel, the two overbridges carrying the roundabout are much wider than the circulatory lanes require, allowing room for pavements and large floral displays.
The A1 runs east west along the old shore line at this point, with the B92 heading north into St Helier on Castle Street. To the south, the road into the port area is another dual carriageway, albeit lined as a D1 with wide cycle lanes, either side of a tree lined central reservation. This route carries the number X1, indicating that it is not part of the roads department network, and instead maintained by another department of the States.