How to fix congestion

Earlier this week the Auckland Regional Council released their “State of the Environment Report”  The whole report makes for quite interesting reading, analysing the pressures faced by Auckland, what steps have been taken to protect the environment from the pressures, and what further steps probably need to be taken. It is an incredibly comprehensive and necessary report, and once again reinforces what a loss to Auckland it will be when the ARC is wound-up into a single Auckland Council. The environmental oversight that they provide is absolutely precious, and I worry tremendously about who, if anyone, is going to replace that role.

Anyway, in terms of transport, the report makes a number of interesting findings. These key findings are outlined below:

• Nationally, vehicle ownership increased from 641 vehicles per 1000 people in 2001 to 698 vehicles per 1000 people in 2007. The Auckland region is likely to have experienced the same or a similar trend.
• Congestion in Auckland shows considerable variability. Travel times in the evening peak have declined for the past three years, however it is too early to tell if this is a longterm trend.
• Between 2004 and 2008, the amount of Vehicle Kilometres Travelled (VKT) in the Auckland region is estimated to have increased by about one billion (nine per cent).
• Nationally, there was steady growth in the engine size of vehicles between 2001 and 2007. However, this rate of growth declined for both New Zealand-new and used imports in 2006 and 2007.

Looking at congestion, there have been some really interesting statistics over the past few years, and many of the fluctuations – particularly between 2007 and 2009 – can tell us a lot about what causes congestion and what is may help ease it.

First, the data:

If we look at the averages for motorways, state highways and arterials, it is quite revealing to note the fluctuations between 2007, 2008 and 2009. On the motorways we’ve seen a continued decline in congestion – which may be the result of a number of factors such as the completion of the CMJ improvements at the end of 2006, an increased use of public transport for longer-distance trips (particularly on the Northern Motorway when the busway become operational) or other reasons – which become a bit more obvious when you look at the stats for state highways and arterials.

The statistics for state highways (the ones which aren’t motorways) show a dramatic decrease in congestion between 2007 and 2008, but about half of that improvement being lost again between 2008 and 2009. For regional arterials, we see a small decrease in congestion between 2007 and 2008, but a large increase between 2008 and 2009 (particularly in the morning peak and interpeak). In short, 2008 was clearly the least congested year on Auckland’s roads.

To try to explain this phenomenon I think it’s worthwhile to see what petrol prices were in these various years. The data referred to above was collected in March 2007, March 2008 and March 2009 so we have a good opportunity to try to see if there appears to be any relationship between congestion and petrol prices. The AA “Petrolwatch” provides the following archive information on petrol prices (recorded at the end of each month):

March 2007: $1.56 per litre for 91 octane
March 2008: $1.78 per litre for 91 octane
March 2009: $1.59 per litre for 91 octane

It would seem as though the level of congestion somewhat mirrors the petrol price. This is not surprising, as petrol prices get higher people will want to drive less, and will consider alternatives such as walking, cycling and using public transport more.

While this is hardly earth-shattering news, it is very interesting to see just how clearly congestion is affected by petrol price. To me, this information shows that if we really want to reduce congestion in Auckland there is only one way to go about it – and that is to get people off the roads, and that one of the most effective ways of doing this is by making driving more expensive.

I suppose that one could argue that congestion has continued to decline on motorways between 2008 and 2009 “on average”, even though petrol prices reduced. However, if you look at the data closely, the time when the motorway is most congested (ie. the morning peak) actually worsened between 2008 and 2009. Considering the amount of money that has been thrown at building motorways in the past three years (and continues to be thrown at this task) it must surely be a disappointment for NZTA that the morning peak times on the motorway continue to become more and more congested – no matter how much money seems to be spent.

Of course there were many disadvantages of having high petrol prices in 2008, and I think that internationally the high oil prices certainly contributed to the economic meltdown later that year. However, it’s worthwhile noting that high petrol prices really do seem to reduce congestion – arguably more effectively than anything else.

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