There’s an interesting report, written by the Manager of Transport Strategy Kevin Wright, in the agenda for Wednesday’s transport committee meeting that looks at congestion in Auckland. In terms of the headline issue, congestion, the report notes that congestion levels are around the same as they were in 2004 (despite how much we have spent on widening and extending motorways). Compared to most Australian cities, congestion in Auckland is relatively low – but at the same time travel time reliability is much poorer than our counterparts across the ditch.
Congestion measures are often flawed though, as for example a road completely free of congestion at all hours of the day probably means we were stupid and spent way too much money in it. It’s helpful to see the report note the limitations of measuring congestion and suggest some ways that assessing the impact of congestion could be done better:
Traffic congestion cannot be represented by a single indicator. To get a broader understanding of congestion, consideration needs to be given to:
- the needs of the user at different times of the day, and by location;
- the performance of the system in terms of the throughput of people and goods;
- the role of the transport system in the economic and social well-being of Auckland (including productivity, access and the costs of travel);
- the extent, intensity, variability (including reliability and predictability) and duration of congestion; and
- the extent to which transport options which can avoid congestion (rail, bus priority lanes, ferries etc.) are utilised.
To accurately assess the ‘impact’ of congestion, a combination of the level of congestion with the proportion of trips experiencing congestion needs to be assessed. For example, while Fanshawe Street in Auckland’s city centre is congested at peak times, approximately 80% of people travelling along Fanshawe Street in the peak are utilising the bus lanes and therefore able to avoid experiencing the delay and trip unreliability caused by congestion. This situation significantly lessens the impact of congestion along Fanshawe Street, even though congestion still exists for general traffic.
This idea of measuring the impact of congestion, rather than just reduced travel speeds for general vehicles compared to what they might be able to do in a theoretical “free-flow” scenario, which once again is nigh on impossible and financially reckless anyway, seems like a really positive step forward. If hardly anyone has to put up with congestion, then the extent to which it is something we need to worry about reduces.
Even more positively than this, the report also picks up on something we’ve talked about a lot on this blog in recent months – the slowing of traffic growth over the past few years. A table in the report highlights that since 2005 the growth of vehicle kilometres travelled on the state highway network in Auckland has slowed considerably (from 3.4% compound growth between 1998 and 2005 to around 1% compound growth since 2005): The report also includes the graph on state highway traffic volumes across New Zealand that we’ve often discussed – which shows a decline in volumes between 2005 and 2011: There’s some interesting discussion around whether this flat-lining is caused by long-term issues or short-term issues, which obviously has huge implications looking into the future. No call is made on whether traffic growth will simply return once the economy picks up again (although from memory the economy was doing OK between 2005 and 2007 yet the growth in traffic had already slowed by then) but possible long term shifts such as cultural change, whether we’ve reached a saturation level of travel, ageing populations and a renaissance of inner city living are all discussed, along with rising fuel prices, as reasons for the flat-lining. There’s also a graph that highlights New Zealand is not alone in experiencing this phenomenon:
The scary implications of all this is highlighted right at the end of the report.
Modelling of future land use and transport scenarios for Auckland forecasts approximately 46% increase in motor vehicle use between 2011 and 2041 assuming full implementation of the transport programme and a high population growth forecast. Modelling takes into account expected population growth, increases in economic activity, increases in fuel prices and traditional travel preferences.
Distinguishing between the ‘short-term’ and ‘long-term’ causes of these recent trends is necessary to determine whether, once the global economy recovers, historical traffic growth trends will return or not. If longer term causes of the recent trends are significant, then future forecasts of vehicle demand may need to be revisited.
If we’re basing the spending of billions upon billions of dollars of money on transport projects over the next 30 years on projections which ignore possible longer term shifts in preferences away from travelling by car, then that seems like a pretty obvious thing to be looking into.
While NZTA and the Ministry of Transport remain in blissful ignorance of all this, it’s somewhat heartening to see that the Council recognises this as a key issue that could fundamentally change how we make future predictions and therefore how we prioritise future transport projects.