The Effects and Efficacy of Large-Scale Motorway Development: A Case Study of Wellington, New Zealand

Abstract

Large-scale motorway development is a common response to traffic issues such as congestion and inconsistent trip times. It is a tool used to alleviate these pressures, which are commonly caused by increasing urban populations and changing urban form. Although best practice motorway development should occur pre-emptively to address these issues, it often occurs instead as a reaction to these effects. Poor motorway planning can have a wide range of adverse effects such as congestion, changes in land use, and an impact on people's wellbeing.

This research addressed large-scale motorway development in the case study of Wellington, New Zealand. A number of key drivers of motorway development, such as congestion and growth, are present in the Wellington Region. The Wellington Smart Motorway and Kapiti Expressway have also recently opened, and Transmission Gully is still in the construction phase. To determine the value of large-scale motorway development the research addressed three research objectives: to investigate current international approaches; to establish and identify the main effects of large-scale motorway development; and to evaluate the efficacy of large-scale motorway development.

The research found that large-scale motorway development can be used to address the effects and impacts of increased vehicle usage. A range of positive impacts were identified, including improved safety, increased road capacity, minimised congestion and improved free-flow speed. Conversely, negative impacts of large-scale motorway development in New Zealand included impacts on urban form, adverse effects for the receiving environment, and impacts on the road user.

It was concluded that large-scale motorway development is an effective tool for managing the effects and impacts of increased vehicle usage. Further, the research is valuable for the NZTA, MoT, GWRC, WCC, PCC and KCDC due to their role as key stakeholders. The research will assist them in making better decisions in the future regarding large-scale motorway development.