Once the network analysis phase of the methodology (figure 15.1, steps 1–4) and the 32 datasets for the aggregated accessibility score(s) (one result for each of the eight core+ activities using each of the four transportation modes) is completed, these results are combined into a composite indicator titled an age group multi-modal accessibility score.
The first step of this data collation phase involves combining the four mode aggregated accessibility scores into a single multi-modal score for each of the eight core+ activities.
The relative importance of each transportation mode varies with the age of the individual and the purpose/activity of the trip. To model this, a weighting matrix was developed to describe the relative mode weightings for travel to each activity type by each age group. The development of the weighting matrix is described in section 15.2.5 and the weighting matrix is provided in appendix E.
The chosen age groups loosely relate to the following stages of life: pre-school, primary school, secondary school, further education/starting work, working and post-work. These age groups have been adjusted slightly to align with the five-year age groups of the Statistics New Zealand census data to facilitate later demographic analysis.
The six age groups used were:
· 0–4 years – pre-school
· 5–9 years – primary school
· 10–19 years – secondary school
· 20–24 years – further education/starting work
· 25–64 years – work
· 65 years and older – post-work.
The following equation describes how each aggregated accessibility score (S) was multiplied by its relative mode weighting (between 0.00 and 1.00) and then summed for all four transportation modes.
The resulting value MAge Group is the age group adjusted multi-modal accessibility score and is separated into two parts. One part is the employment age group adjusted multi-modal accessibility score, and the other is the consumed age group adjusted multi-modal accessibility score.