## Step 5 – age group adjusted multi-modal accessibility score

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.

This equation was applied once for each
of the six age groups, combining the four mode results into a single multi-modal
result for each activity type. This resulted in 48 datasets (six age groups * eight
activities * one multi-modal dataset).

The resulting value M_{Age 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.