The road network around the Basin Reserve currently accommodates significant local and strategic movements; both north-south and south-north traffic flows between the Wellington CBD and Wellington’s southern suburbs, and traffic flows of State Highway One (SH1). Between the Terrace and Mount Victoria Tunnels, SH1 eastbound and westbound traffic flows follow different street systems to the routes known as the Wellington Inner City Bypass.
Eastbound traffic exits the Terrace Tunnel and follows Vivian Street and Kent Terrace, approaching the Basin Reserve from the north, before travelling along Paterson Street to the Mount Victoria tunnel. Westbound traffic exits Mount Victoria Tunnel and approaches the Basin Reserve from the east, before travelling along Buckle Street to the Terrace Tunnel.
The street system around the Basin Reserve functions like a very large roundabout with traffic signals. Traffic moves clockwise, with major entry and exit points distributed around the periphery. Daily, about 26,000 vehicles enter from Kent Terrace, with 18,000 vehicles exiting towards the Mount Victoria Tunnel, heading east. These flows are replenished by another 18,000 vehicles which come onto the roundabout from the Mount Victoria Tunnel heading west. Therefore, an undiminished flow of 26,000 vehicles moves around the southeast and south of the Basin. Of these vehicles, 8,000 exit the Basin heading south on Adelaide Road; 14,000 vehicles join the flow from that same road. The largest traffic flows, comprising 32,000 vehicles, travel around the southwest and western sides of the Basin Reserve (Sussex Street). Of these, 22,000 exit onto Buckle Street on the northwest corner and 10,000 travel to the northern exit at Cambridge Terrace.
Congestion and varying travel times can make time-critical journeys to work or school difficult, and the movement of freight can also be affected. While there are a number of projects in the works to address some of the issues individually, it is important to get this entire stretch of road working well.
Without intervention, congestion and journey times along the route are predicted to increase by up to 75% by 2021. That means that if we don’t take the right steps to sort this out now, then by 2021 it will take about 16 minutes to from Cobham Drive to Taranaki Street. With the T2T improvements in place, the same trip will only take 10 minutes.
The T2T brings together three key pieces of work: the Basin Bridge, the Improvements to the existing Inner-city Bypass and the National War Memorial Park and Underpass. By integrating the three separate T2T projects into one, the NZTA can ensure that the highest level of benefit is gained from the significant investment being made.