The New Zealand Transport Agency's rationale for opting for a flyover rather than a tunnel at Wellington's Basin Reserve has come under fire by independent transport experts.
In a peer review ordered by the Environmental Protection Authority, consultant company Abley says the agency has been inconsistent in the way it has assessed the five different proposals for the Basin.
Initially the Transport Agency was looking at two flyover options, two roading options and a tunnel to ease congestion at the Basin Reserve.
Abley's concern is that the agency used cost to justify not going ahead with a tunnel, but ignored that as factor when dismissing the two cheaper roading options.
The agency says cost was not the only factor, as topography and ground conditions also went against the tunnel.
It is also concerned Abley did not contact it when the first report was written in November last year and never visited the site.
The flyover proposal goes before a resource consent hearing in February.