As many of us will have experienced when driving, walking, or cycling, in New Zealand, some of our older highway bridges do not provide facilities to safely accommodate people crossing by foot, cycle or micro-mobility vehicles.

Resolve Group’s Jamie MacDuff was involved in a recent NZTA project which sought to provide safer shared paths on three older state highway bridges in Waikanae and Ōtaki. “The safety improvements for pedestrians and cyclists offered by projects like this are compelling,” says Jamie.

Part of a wider programme to improve the old SH1 route through Kāpiti, the project provided three new walking and cycling clip-ons for three old state highway bridges using an innovative, cost-effective, lightweight design employing composite materials instead of the more conventional steel build. “The use of fibre reinforced plastic as a structural material for bridges and walkways isn’t common in New Zealand,” says Jamie, “but we are seeing increasing use overseas. It promises low maintenance, a long asset life and low mass compared to steel and timber and has cost advantages for some projects.”

Despite challenges, including a one-way detour at Waikanae, which created short term pain for locals, Jamie says, “when compared with other installation methodologies and scaffold options, these structures can be installed with less impact on the local community.” And indeed, the public response to the finished clip-on has been only positive. “As an industry, we should always be on the lookout for opportunities to innovate and improve,” says Jamie.

Along with promoting this innovative design solution, Jamie provided project management and delivery support to NZTA. He led options investigations, procured suppliers, managed regular progress reviews and facilitated the resolution of services clash issues with designers, and installation challenges with contractors, over an extended delivery period. The Waikanae bridge clip-on was completed in April 2024. The installation of clip-on shared paths to the Waitohu Stream and Ōtaki River bridges further north has now begun.

New Zealand’s infrastructure spend is giving us lower value for money than almost every other country in the OECD according to Ross Copland, former Chief Executive of the NZ Infrastructure Commission Te Waihanga(Copland, 2024), and this needs to change.

NZ Transport Agency Waka Kotahi (NZTA), recognising that it had a gap in the monitoring and evaluation of its investment costs, recently commissioned Resolve Group to examine whether the variability of costs for common transport investments could be quantified, and what might be done to mitigate any differences.

Assessing a sample of 21 similar intersection improvement projects (typically highway roundabouts or local road intersection improvements) delivered across New Zealand from 2016, the research, led by Dr Carron Blom and Jamie MacDuff, found that despite the physical similarities in many of these projects, there was a very high level of variability in the indexed costs of these projects on a unit area basis, even when outliers were excluded. The research could not find any correlation between out-turn cost per sealed area and the nett effect of key project cost factors (such as pavement type, level of traffic management etc.) or other factors that could be influenced by the NZTA.

Our experience at Resolve Group is that a ‘whole-of-system’ approach is necessary for New Zealand to collectively meet its current and future infrastructure needs and indeed, the research revealed the need for system-level mitigations to be able to effectively monitor and evaluate actual investment costs.

To enable NZTA to establish a benchmark for cost variability, and to support changes within its operating practices (such as the recently developed standard methods of measurement (SMoM) and improved definitions for cost elements ), Resolve Group has proposed a range of interventions that aim to reduce variability in cost measurement and reporting that are embedded and/or created within organisational policies and procedures, and to enable infrastructure costs to be more comprehensively recorded, understood, and used to help manage, monitor and  forecast future investment costs, and so improve value-for-money infrastructure delivery.