The NZ Herald is running a story today based on a study of Auckland’s most congested areas. According to the study, the worst congestion in Auckland is for those trying to make the trip between the city centre and Takapuna:
Morning traffic queues back from the Northern Motorway’s Esmonde Rd interchange mean Takapuna commuters face a harder slog to work for the distance travelled than other Aucklanders.
Navigation equipment supplier Tom Tom has found that it takes an average of 18 minutes longer to drive from Takapuna to Auckland in the morning travel peak than in free-flowing traffic, when the trip takes just over 10 minutes.
That puts Takapuna ahead of all other surveyed Auckland suburbs in terms of delays in proportion to trip distances, according to statistics gleaned from users of its GPS-based equipment.
But the return journey in the evening peak takes just 17 minutes, making it the fifth easiest of the 24 suburbs surveyed to get home to.
I must say this result took me a little by surprise. Takapuna seems to have pretty good transport options and while at peak times it may take longer to travel than at off-peak times, the trip is still fairly short.
What this story highlights is what I think is a weakness in measuring congestion in the way the study did – a point that the Human Transit blog elaborated upon quite well in this recent post. The criticism is probably best explained by the simple diagram below:
I suppose this highlights why I have concerns about using ‘congestion’ as the main measure of how good a city’s transport system is. Under the methodology used, if a city was gridlocked 24/7 then it would actually get a really fantastically low congestion score – because there would be no difference between travel times during the peak and outside the peak.
Other measurements, like ‘trip time reliability’ or ‘average speed’ would seem more obvious measurements of ‘mobility’, while ‘percentage of city within an “x” minute trip” would seem the best way to measure accessibility. One does wonder whether many of the poor transport decisions we make are the result of obsessing over ‘congestion’ rather than the more fundamental transport issues of mobility and accessibility. Takapuna certainly seems to me as a part of the city with pretty good mobility and accessibility, even if its roads get clogged up for a couple of hours each day.
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As an semi-frequent visitor to this part of Auckland (from Dunedin), what strikes me most is the number of additional lanes and bits of road that have been added in around there, simply to accommodate long lines of traffic for perhaps an hour each day. And really, it does have fantastic transport connections.
In medical circles, these types of measurements are referred to as ‘relative risk’ and ‘absolute risk’. As in this example, the ‘relative’ calculation makes the situation in Takapuna seem much more dire, whereas in ‘absolute’ terms, it’s still a good commute. Actually, the medical analogy works well. The new treatment ($50m of roads, stat) will produce a 50% decrease in travel time [but is only 30s].
Chris Darby is wrong. Opening up the bus lane to high occupancy vehicles will be a disaster. The vehicles will still have to merge to get onto the motorway onramp and then merge again at the end of the onramp. The only way that this could possibly work would be if the HOVs were able to drive on the section of busway between Esmonde and the bridge. Then why not open up the whole busway network? Oh wait… that is the plan.
As a frequent traveller around the Devonport peninsula, the traffic on Lake Rd is slow almost all the time. Accordingly I try to travel by ferry as much as I can, I personally think you’d be crazy to drive to work in the CBD from Devonport during peak times when it would take close to an hour when you could ferry for just 12 minutes. Off peak I think there is a case to improve ferry frequencies (and 813 bus frequencies) to every 15 minutes (currently half hourly) and Bayswater to every half hour (currently hourly and only a couples of times a day during weekends)
The congestions was measured using GPS data, that I assume was in private vehicles. Therefore its only relative to congestion for car commuters. Anyone on a bus from takapuna or a train from Ellerslie would not be in this survey.