This report outlines the development of a methodology to calculate neighbourhood accessibility in New Zealand by considering land use activity and transport mode opportunities for different demographic groups.
At the commencement of this report the question was posed, ‘What is access and mobility?’ This report has demonstrated that accessibility is more than simply achieving access because access by itself doesn’t describe the quality of choice or ease of being able to reach a destination. Additionally, although mobility is a component of accessibility, simply improving mobility may not actually achieve improved accessibility. Accessibility then needs to be considered as its own area of study. Consequently traditional transport modelling tools are not appropriate means to measure accessibility and hence the development of the accessibility analysis methodology presented in this report.
The methodology included in this report includes a series of negative exponential equations developed for the four transportation modes of walking, cycling, public transport and private vehicle through an analysis of the NZHTS. The need to refine these values based on journey purpose has been identified but a larger sample size is required before these can be further progressed.
A fundamental difference between services one consumes which provide homogenous levels of service and a heterogeneous activity, ie places of employment, was identified. A harmonic series was selected to model the saturation of opportunity of consumed activities and the overall accessibility to supplied activities and places of employment within a city were summed together.
The accessibility methodology was tested in a case study for Christchurch city. This showed the spatial scalability of the methodology, as it can be run at both meshblock and individual parcel level without modification. The ability of the methodology to identify the impact on accessibility of both land use and transportation network changes was demonstrated by modelling the impact of a new hospital in Halswell, and a scenario where a bridge was located across the mouth of the Avon – Heathcote estuary.
Overall the authors consider the methodology developed and presented in this report is a step-wise improvement for the consideration of integrating land use and transport rather than only considering traditional three or four step mobility modelling. The more detailed and transparent treatment of a critical variable determining people’s attitudes and behaviour – accessibility – means that capabilities, opportunities and mobility can be considered explicitly, rather than incorporated in travel demand assumptions as is common in the four-stage models.
During the development of the accessibility calculation methodology outlined in this report, a number of potential areas for refinement and further research were identified. These are discussed in the following chapter.