7. Summary of Findings and Possible Applications
7.1 General Findings
The analysis of the position in Auckland, and in particular for Auckland City, suggests that there are positive linkages between:
- Accessibility and density.
- Density and productivity/average incomes.
Within Auckland City, the central area combines high densities and high incomes. Other areas within the city, particularly Ellerslie South, experience similar conditions. For these areas, the relationships are particularly strong and relatively robust, while the observed elasticities are in line with the results noted in the overseas literature.
In the other cities in the region, higher employment densities are again typically associated with higher levels of productivity (although areas in these cities exhibit lower densities relative to Auckland City). The relationships are less sensitive and less statistically robust, but there is still evidence of a positive relationship between density and productivity, implying that agglomeration impacts do exist.
Looking at the relationship between accessibility and employment density a similar pattern emerges, with a reasonably strong relationship in Auckland City and a weaker but still positive relationship elsewhere.
It should be noted, however, that while positive relationships appear to exist, the results presented here should be regarded as preliminary only and are potentially subject to revision with further investigation in this area.
7.2 Developing a Forecasting Model and Application in Scheme Appraisal
The identification and quantification of the relationships provides a means of assessing the potential effects of changes in accessibility on the potential employment densities, and on the consequent levels of productivity and output. This potential impact is likely to be particularly substantial where the accessibility to existing major centres is improved. The process is set out diagrammatically in Figure 7.1.
Figure 7.1: Forecasting Model
Using the quantified relationships, the potential effects of changes in accessibility on employment density can be assessed, with improved accessibility giving rise to forecast changes in the numbers of jobs likely to be achievable in specific areas. This increased employment will generate the increased output from the additional workers and by raising employment densities will also contribute to an increase in productivity and output for the existing workforce. Both these factors will contribute to an overall increase in economic output for the affected areas.
The increase in total output estimated using this approach is not captured by existing conventional appraisal methods, particularly as is typically the case when fixed land uses are assumed. In principle, therefore these benefits represent an addition to the total economic benefits of a project as conventionally calculated.
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