Apart from the connection to Davey and Macquarie Streets, the major intersection with streets in the CBD is the three-lane roundabout at the north-east end of Liverpool Street. Because it was built in close proximity to the main railway station at the time, the roundabout was, and continues to be, called the "Railway Roundabout". The sunken garden in the centre of the roundabout functions as a pedestrian thoroughfare, with under-road tunnels connecting to the two sides of Liverpool Street, the original site of the railway station to the north-east, and to the Domain and the suburb of The Glebe to the north-west. The roundabout was originally just an un-controlled intersection, but with the gradual increase in traffic, particularly from the eastern shore of the Derwent, it was often in grid-lock at peak travel times. Traffic lights were introduced and alleviated the situation, and later construction of the direct links from the Tasman Bridge to Davey and Macquarie Streets further relieved the pressure. Other streets from the CBD provide access to the highway, but for much of its length to the city boundary at Risdon Road it is limited access road.