A new report out of the USA supports a hypothesis that we’ve been talking about for quite a while on this blog: that traffic growth is stagnating across the world for a variety of reasons – and this has a compelling long term impact on our transport policies.

Some of the key findings from the report are outlined below:

From World War II until just a few years ago, the number of miles driven annually on America’s roads steadily increased. Then, at the turn of the century, something changed: Americans began driving less. By 2011, the average American was driving 6 percent fewer miles per year than in 2004.

The trend away from driving has been led by young people. From 2001 to 2009, the average annual number of vehicle miles traveled by young people (16 to 34-year-olds) decreased from 10,300 miles to 7,900 miles per capita—a drop of 23 percent. The trend away from steady growth in driving is likely to be long-lasting—even once the economy recovers.

Young people are driving less for a host of reasons—higher gas prices, new licensing laws, improvements in technology that support alternative transportation, and changes in Generation Y’s values and preferences—all factors that are likely to have an impact for years to come.

Federal and local governments have historically made massive investments in new highway capacity on the assumption that driving will continue to increase at a rapid and steady pace. The changing transportation preferences of young people—and Americans overall—throw those assumptions into doubt. The time has come for transportation policy to reflect the needs and desires of today’s Americans—not the worn-out conventional wisdom from days gone by.

Some of the statistics are pretty amazing: a 23% fall in the average vehicle miles travelled by young people in only eight years! Per capita travel peaked in 2004, well before the economic difficulties of the past few years:

usa-vmtThere are other supporting statistics which make for interesting reading too:

  • In 2009, 16 to 34-year-olds as a whole took 24 percent more bike trips than they took in 2001, despite the age group actually shrinking in size by 2 percent.
  •  In 2009, 16 to 34-year-olds walked to destinations 16 percent more frequently than did 16 to 34-yearolds living in 2001.
  • From 2001 to 2009, the number of passenger-miles traveled by 16 to 34-year-olds on public transit increased by 40 percent.
  • According to Federal Highway Administration, from 2000 to 2010, the share of 14 to 34-year-olds without a driver’s license increased from 21 percent to 26 percent.

What the report helpfully does is then delve into some of the reasons behind the pretty dramatic changes: looking at things like higher fuel prices, the toughening up of licensing, improvements in technology, a changing culture and so on.

As always, the critical question is whether these statistics are just a ‘blip’ caused by the recession and slow economic recovery, or whether they are likely to indicate a long-term change. This is a really important question because it determines the extent to which we really do need to change our longer-term transport policies. Of course the only proper answer is to say that “we just don’t know for sure”, but there are some interesting suggestions in the report that the trends are here to stay:

The recession has played a role in reducing the miles driven in America, especially by young people. People who are unemployed or underemployed have difficulty affording cars, commute to work less frequently if at all, and have less disposable income to spend on traveling for vacation and other entertainment. The trend toward reduced driving, however, has occurred even among young people who are employed and/or are doing well financially.

  • The average young person (age 16-34) with a job drove 10,700 miles in 2009, compared with 12,800 miles in 2001.
  • From 2001 to 2009, young people (16 to 34-years-old) who lived in households with annual incomes of over $70,000 increased their use of public transit by 100 percent, biking by 122 percent, and walking by 37 percent.

For Auckland, what will be interesting is to see whether reductions in per capita driving are swamped by the massive population growth anticipated over the next 30 years or not. If not, then pretty much every new roading project planned for over the next 30 or so years may not actually be necessary.

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  1. These trends are fascinating – especially the breakdown of trends between young people who are well-off and those who are not. The most commonly heard retort to claims of stagnant traffic growth from the highway addicts (such as NZCID) is that the flat-line in travel demands is related to the slow economy. This kind of data is showing that it’s not – it’s actually a function of changes in personal preferences.

    I write this from Brisbane and the same trends seem to be emerging here. Although in Brisbane the divergence between travel demands and roads-focused policy/investment has been quite catastrophic: A number of highway/tunnel PPPs have gone belly up – primarily (it seems) because of over-egged demand forecasts.

    The risks to NZ from the RoNs seems quite stark: This Government is rushing headlong into our largest ever highway building programme (RoNS) despite flat-lining traffic demands for the last 5-10 years. Construction most of these projects should be delayed as much as possible …

  2. This follows on from earlier posts (see the Myths section “Traffic volumes are growing” – accessible via the “Myths” link at the top of the page or via this link: http://greaterakl.wpengine.com/2012/03/29/unprecedented-change-kiwis-driving-less-and-loving-it/ ).

    Firstly – I think even NZTA are starting to get the message finally – their traffic counting page at http://nzta.govt.nz/network/operating/counting-traffic/index.html no longer says “Traffic volumes are growing see how much” as the title for green box that gives the link to the detailed traffic stats – it now says “View the latest State Highway traffic volumes monthly reports”.

    So maybe, just maybe NZTA realise that they aren’t actually growing any more (or maybe the NZTA PR department reads this very blog)?

    Secondly (bit of a shaggy dog story this, so bear with me here or skip to the next persons comment …)

    While looking at the latest stats (at this link http://nzta.govt.nz/resources/state-highway-traffic-growth/docs/shtg-201211-appendix.xls) which I did a week or so back and check the stats for the Harbour bridge (as its the latest report available).
    Two things stand out. I assume the numbers are Average Vehicles Per Daily numbers (“VPD”) for that month as for the bridge 160,000 vehicles a day is about normal daily traffic as I recall.

    1. The Excel sheet has two sheets in it – on named “All Data” the other named “HV Data”
    – the HV data has no measurements for any (I assume “HV”) traffic on the Harbour bridge – so presumably NZTA can’t separate out HV traffic from normal traffic on the bridge but can everywhere else – what gives?

    2. The “All Data” sheet has 3 entries for the Harbour bridge “Centre Span”, “Left Clip-on” and “Right Clip-on”, but annoyingly enough it doesn’t say which direction the “Left” and “Right” clip-ons are considered from (and why call them Left and Right Clip On to make it ambiguous – why not say “NB Clip-on” and “SB clip-on” and make it perfectly clear like you do for other counters like “Bombay SB” and “Bombay NB” NZTA guys and gals? (but I digress).

    The point of interest here is that the stats we have there only go back to Nov 2011 and give monthly numbers up to Nov 2012, but if you look at the monthly totals for the left and right clip ons you will note that most of the year the volumes of these left and right clipon VPD totals are pretty much the same as you’d expect both clip ons have the same number of lanes (2) and therefore the NB and SB traffic volumes would over time (month/day etc) match up. But they don’t quite, some months of the year the difference is around 500VPD in the favour of the right clip on lanes most months (thats probably because Right clipon means the “SB” clipon, which due to the Off ramp on the SB clipon has slightly lower traffic VPD. But in some months, Like Nov 11, that difference is much higher – some 2,820 VPD.
    December 2011 shows a higher difference number than that, but I am sure that is due to the annual bridge clip-on shut down over Xmas so will exacerbate the difference making any comparison meaningless.

    If you compare the Centre span (of 4 lanes) traffic totals with the two clip on lanes added you’d expect to see about 50% of the traffic on the Centre span, and 50% on the clip ons right? since these two numbers cover 4 lanes each? Well actually if you think about it – you’d expect the centre lanes to carry more HV vehicles (to lighten the load on the clip-ons) and therefore because HV vehicles are slower and generally longer there will be room for fewer cars/light vehicles as compared to the clip-ons – and this is the case, the split between the clips on lane totals and the centre span totals is about 57% clip ons/43% centre space.

    I assume this is also in part as the clipons are always usable for traffic in both directions (annual maintenance work aside), whereas with the centre span has the tidal barrier (aka “the snake”) and so the lanes move around between 2 NB/2 SB to 1NB/3SB, then 2NB/2SB, then 3SB/1NB and back to 2NB/2SB over the course of a Midnight to Midnight “day”.
    So this fact means that for some of the time all four lanes on the centre are not evenly used. I think it probably indicates that once the tidal flow has peaked, most of that tidal lane is effectively only partly used – which therefore reduces the total traffic counted on the centre span until the tidal lane is returned to the other direction to become 2NB/2SB etc..

    But heres the point of this ramble – an interesting fact I see in these numbers is that in some months of the year this split between centre and clipons VPD is quite a lot higher, Feb and Mar 12 have the highest absolute differences of some 15,270 and 16,607 VPD between clip-ons and centre span. Most of the year the difference between the traffic for centre lanes and the clipon totals is about 11,000 to 12,000 VPD,(in the clipons favour) and in April it dropped to a yearly low of 7051 with the next lowest being Jan-12 at 9,917 – again, likely due to road works on the bridge clipons there I expect. So what we see is that the VPD differences seem to be in the centre span and the clipons, run pretty much at between 42-45,000 VPD, so the monthly fluctuations are in the end mostly due to centre span traffic changes I think.
    So shows that the clipons are running reasonably well, at about 21,000 VPD per lane over 4 lanes, and the centre span – not so much – at an average usage of only 17500-19,000 VPD per lane.

    So, what does it all mean?I think that maybe the tidal lane on the bridge is not being efficiently managed currently (cost cutting reasons?) and also that the HV traffic portion is quite a lot higher on the centre spans?

    Anyone got any reason why the centre/clipons split comes and goes when it does, and does it tell us anything about the annual “March Madness” and/or maybe the result of the VPT opening or other CMJ improvements? Since we can’t know how much HV traffic is impacting these numbers its hard to know off hand,but someone might have some insight.

    Also since peak capacity of a lane is about 2200-2400 VPH as I recall , then that shows that the bridge usage of most lanes is at maximum capacity for 10 hours a day of the 24 hours possible, which given that most of the other 14 or so hours are “night time” or other non-peak times, indicates that all the bridge lanes are actually pretty busy most of the day.

    I’ve got a graph or two of these numbers and such, if anyone can tell me a simple way to add a picture to a post comment I’ll put them up as a screenshot (PNG format) in a follow up post for all to see what I mean.

    1. some other factors to take into account on the AHB are that the bridge lanes, particularly adjacent to the moveable barrier feel, or are narrower than the clipon lanes, both with the barriers in the centre and offset so the bridge lanes may be avoided by less confident drivers particularly if there are heavies on the bridge

      second, quite a bit of southbound traffic comes onto the motorway at Onewa and may naturally stay in the left lanes rather than battle across to the bridge lanes, there’s plenty of lane changing space on St Marys Bay if you want to go south

      third, if you’re going into the CBD, then the clipon lanes take you right through to Fanshawe or Cook

    2. Greg I think I can answer some of your points.
      – The NZTA do have an idea of how much heavy traffic is using the bridge but they don’t seem to release it, just like they don’t release any other data points from places like SH16 or even other parts of SH1. In the annual numbers it says that 5% of the traffic is heavy.
      – I have always assumed that the left means northbound and right means southbound but I think your point is valid and they should clarify which is which.
      – You can get the monthly data back to Sep 07, the spreadsheets only show the last years worth of data but if you go back to the monthly numbers of previous years it will show the previous year from there.
      – Not sure as to why the the difference between the clipons and centre span changes.
      – I would say there are probably a couple of reasons why there is a big difference between the usage of the clipons and centre span though. First as you identify the tidal nature of them would remove some capacity but the other and possibly bigger reason is the nature of the lanes themselves. They are narrower than the lanes on the clipons and as such a lot of people prefer not to drive on them. This is especially the case with trucks who already take up a lot of road space as it is.

      Another interesting fact is that southbound clipon has less weight on it than the northbound one. This is because often the trucks heading north have left the port with a full load where as the trucks going south are more likely to be empty.

      1. Just like to add that buses are defined as Heavy by NZTA so increases in bus numbers after the busway opened read as increases in HVs… figures always used by trucking industry [and George Wood] to argue that investment must keep going disproportionately to more highways and none to Transit….

  3. I thought I read a post saying this just recently, maybe on another blog?

    The “kids”/”hipsters” definitely want to be in inner city neighbourhoods, but “gentrification” makes this difficult – young people can’t afford a box in Torbay or Flat Bush (even to rent), let alone Ponsonby or Grey Lynn (even to rent).

    I think the trend is becoming clear that more and more people want to be able to walk to things, or take good PT, especially younger people, and especially as the cost of running a car is getting out of reach (like housing).

    Something’s gotta give.

    1. I’d probably be almost a hipster if I was a little more hip, although maybe I’m more like the gentry these days as much as I’d hate to admit it. Anyway, the inner city is the only place I could afford to buy. A house in Torbay or Flatbush cost twice as much as my inner city apartment, simply because my place required my to buy very little land and spend more on the actual dwelling. Anywhere else you spend two or three times the value of the actual dwelling on the land it sits on. Indeed I want to be able to walk to things, ditch the car and rely on PT, and did. I think the only thing that has to give is the idea that everyone wants to live in a separate house on a section and drive for their transport.

  4. It’s a good trend. But I have just been on the Inner Link bus and despite being over 60, when I got on I would have brought the average age of a nearly full bus down – not up. I suppose the gold card has a lot to do with it but the fact remains that there are an awful lot of elderly people using PT these days: old habits can be changed if the incentives are correct!
    No gold card for me btw: a little longer for that.

    1. The incentives: little to no investment in public transport and free PT travel. Mind you it’s the government that forced the change to car travel so can’t blame the people for how their dollars have been spent.

  5. Friends I know who have good jobs in the great US of A worry about job security.
    The economy and life in general for all but the fortunate few is but one paycheck away from disaster.
    For this reason they take PT and are squirreling away money for a rainy day.

    Perhaps not every data point can be automatically be attributed to the self enforcing beliefs that is the Auckland Transport Blog echo chamber.
    Not saying you are wrong, not saying you are right, but can you see there be some shades of grey in life?

    Grrrr, back from the Christmas break, Santa was a cheep bastard, so so angry.

    Angry Bob

    1. “For this reason they take PT and are squirreling away money for a rainy day.”

      Might I add that all the squirelling away in the world and using PT won’t help them if they don’t have a job and one of them gets seriously sick…
      So yeah I can see why they’re concerned, makes you realise there is more to life than money though, and maybe having a decent health system is actually more important to the economy than good PT and fast Internet.

      Sorry to hear Santa was so mean, but stick around I’m sure the fireworks this year from Central and Local government will make up for it 🙂

  6. I think the absolute most important factor is the increase in oil prices since 2005 or so. Changing preferences etc may have a part to play, but money talks. Especially in the US – tax makes up a fairly small part of the petrol price there, so that means if oil prices rocket then so do petrol prices. I’m pretty sure that that will be the main influence. In NZ, taxes make up more of the petrol price so this acts as a buffer on prices to some extent.

    It’s no coincidence that travel in the US, NZ and the rest of the world has been falling since 2004/5. That’s when prices started to go up majorly – they’re currently two or three times what they were in the early 2000s.

  7. Having mild CDO (that’s obsessive compulsive disorder with the letters put in the correct order), I’ve religiously recorded my kilometrage for yonks: 1990s, average 14k km/yr; 2000s: 11k km/yr; currently 8k km/yr. I have no idea what that means; maybe demographics (sigh).

    However I don’t think that petrol price is a major factor as I haven’t downsized, and my cars have become progressively more fuel-efficient. And IIRC, current fuel prices relative to average income are much the same as in the 70s (although they may have dropped relatively for a period within that time frame). But as JohnP mentions, in NZ excise tax is high, around 70% of the pump price I think, so governments can manipulate this big-time if they choose.

    1. NZ’s petrol tax is about, IIRC, the fourth lowest in the OECD. So it isn’t high by world standards but is high for those that believe that tax never performs a useful function. Not as low as the US. Ironically the low US fuel tax makes their pump price more volatile; more susceptible to shifts in the price of crude unlike places where the tax makes up much more of the retail price. It also means that the State Highway system has been underfunded for decades and is falling into serious disrepair in places despite the addition of funds from general taxation [or borrowing to be more precise].

      1. I’m not arguing against excise duty or GST on fuel, just simply making the same point as you are Patrick, that retail price volatility can be managed by this means, while providing revenue for roading maintenance and maybe some capital works. Either the present government or the previous one, can’t remember which, finally did the right thing and allocated this excise duty fully to roading. It’s perfectly fine to borrow for long-term capital works, but maintenance costs should always come out of revenue. Excise duty and GST, both being consumption taxes, are quite a different thing from general (ie income) taxation. Excise duties on products such as alcohol and tobacco are used for social engineering purposes, but in all fairness I don’t think that applies to fuel tax.

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