11 Mar 2015
Gateway WA constructing a WA first in interchange design
As construction of the Leach Highway / Abernethy Road and Tonkin Highway / Horrie Miller Drive / Kewdale Road interchanges advances at a rapid pace, road users will soon be using the first single point urban interchanges in Western Australia when they are opened later this year.
The length of right turn lanes needed to accommodate future traffic flows at these interchanges using the traditional diamond layout design were hindered by physical constraints. This led the design team to exploring other options for the design of the interchanges and as a result the single point urban interchange (SPUI) design was chosen.
The SPUI design enables a single set of traffic signals to safely control each pair of opposing right turn movements at the same time. This allows the efficient movement of large traffic volumes which are experienced at both of these interchanges on a daily basis.
It significantly improves efficiency compared to the traditional split diamond interchange and reduces traffic signal phasing typically from four phases to three, which improves traffic flow.
With an increased radius for road users turning right at the interchange, the design also facilitates easier movement for large and oversize vehicles.
As further traffic restrictions and temporary movements come into play at these intersections over the coming weeks, road users are asked to factor extra time into their journeys as the interchanges progressively move towards their final design.