Auckland Transport released new patronage data, and FigureNZ tidied it up to make it easily computer-readable, so I thought I’d look at some of it. What I’m going to show is a decomposition of the data into overall trends, seasonal variation, and random stuff just happening. As usual, click to embiggen the pictures.
First, the trends: rides are up.
It’s hard to see the trend in ferry use, so here’s a version on a log scale — meaning that the same proportional trend would look the same for all three modes of transport
Train use is increasing (relatively) faster than bus or ferry use. There’s also an interesting bump in the middle that we’ll get back to.
Now, the seasonal patterns. Again, these are on a logarithmic scale, so they show relative variation
The clearest signal is that ferry use peaks in summer, when the other modes are at their minimum. Also, the Christmas minimum is a bit lower for trains: to see this, we can combine the two graphs:
It’s not surprising that train use falls by more: they turn the trains off for a lot of the holiday period.
Finally, what’s left when you subtract the seasonal and trend components:
The highest extra variation in both train and ferry rides was in September and October 2011: the Rugby World Cup.