Different streets in Māngere were treated differently. The streets with the most traffic were called arterial streets, and streets with medium amounts of traffic were called collector streets. Both these types of streets got new or improved facilities for walking and cycling, such as crossings and bike lanes. The streets with the least traffic, which were mostly residential, were called local streets. These streets had changes to slow traffic speeds and discourage through traffic.
We used tubes laid on the road to measure the speed and number of vehicles. Councils often measure traffic in this way.
We did these tube measurements in two neighbourhoods. Māngere Central was the ‘intervention area’, where the street changes were made. Māngere East was the ‘control area’, where our project made no changes. We did the tube measurements before the street changes, in 2014, and also after the street changes, in 2017.
Once we had the measurements, we looked to see if they had changed between 2014 and 2017 in each area. We also checked whether the change in the intervention area was different from the change in the control area – this was how we worked out the effect of the street changes.