Why off-peak matters

Posted: December 9, 2011 in Transport
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The challenges of providing good public transport is actually quite a different approach depending on whether it is for the peak or off-peak period. Most of the focus tends to be on the peak period, during which services tend to be relatively frequent but often run into capacity constraints. The result is things like not enough road space for buses to come into the city and drop people off or overcrowding on trains. Essentially, supply just can’t seem to keep up with demand. On the other hand, capacity is rarely a problem during the off-peak, where instead it’s a lack of commuter demand that leads to lower frequencies, often as low as half hourly or hourly services and sometimes not at all on weekends.

There’s no hard definition of peak hour, it depends on where you are, what form of transport you are taking and where you are headed, but broadly it is 6:00AM through to 9:30AM for the morning peak and 3:00PM to 6:30PM for the afternoon peak. The morning peak is more compressed, with very large numbers of people going to work or to school in the 60 minutes before 9AM. The afternoon peak, on the other hand, is more spread out. I’m guessing this is primarily due to school ending 2 hours before most workplaces, but also from people not always leaving work on time or things like staying behind for a drink with the workmates before returning home. Off-peak is the rest of the day, as well as weekends.

As a rough rule of thumb, one third of all public transport trips occur during the morning peak, one third during the afternoon peak and one third during off-peak (with most of this occurring between the peaks – i.e. 9:30AM to 3:00PM). Not only does peak hour account for the majority of patronage (about 2 out of every 3 trips), but it’s also much more suited to public transport as it’s primarily work travel. About a third of all jobs are clustered around major centres, which in Sydney are places like the CBD, North Sydney, Parramatta, Liverpool, but also business parks like Macquarie, Norwest, Rhodes or Olumpic Park.

Public transport is quite successful during peak hour. You can measure this by looking at journeys to work (JTW), which measure the proportion of trips to work based on the primary mode of transport. The 2006 census found that in Greater Sydney, public transport had a 26.3% JTW share (source), and this gets as high as 70.0% in the CBD (source). Meanwhile, the Household Travel Survey from 2007 finds that for ALL trips (including work and non-work trips), public transport’s share of trips falls to 10.8% (source). This latter figure is a bit misleading, as about 18% of all trips are on foot, so stripping out this figure gives a public transport share of non-walking trips of about 13%. And remember that this isn’t just for non-work trips but rather for ALL trips, so we can expect non-work trips (a proxy for off-peak) to be even less than that.

So the off-peak has fewer services and lower patronage. This leads to a bit of a chicken vs egg debate. Did the service levels get cut because demand wasn’t there, or is demand low because the service levels are insufficient? It’s probably a bit of both, and I’m not going to try to argue that if you had peak hour level frequencies then you’d get peak hour level patronage. But I do think that off-peak services do matter.

And here’s why:

  1. During the off-peak, it’s very important for transport to offer everywhere to everywhere services. This is because travel during the off-peak is much less likely to be of the suburb to major centre type that peak hour transport is. But this doesn’t mean having bus routes that pass right in front of your house that can take you anywhere else in Sydney. What it means is having frequent services that take you to an interchange, where you can get another service that takes you where you want.
  2. Peak hour is very well patronised, and probably breaks even or runs at a profit. But off-peak is not, and as a result public transport only recovers 25 to 50 cents in fares out of every dollar it costs to run. In order to increase the cost recovery, patronage needs to be improved during the off-peak.
  3. Increasing public transport use means more voters are using the public transport system. Almost all voters are regular drivers, but only a minority are regular public transport users. In order to build strong political support for improvements to public transport, an increase in the number of users is needed.
  4. Few capacity constraints exist during the off-peak, with the system designed to take on the much busier peak periods. The track, trains, buses and stations are there and paid for whether they are fully utilised or not.

To quote Jarret Walker of Human Transit: frequency is freedom. The PTUA in Melbourne has been running a 10 minutes to everywhere campaign for a few years now, where all trains, trams and major buses would run at 10 minute frequencies all day. This is important because it makes walk up and go transport possible, which is necessary in order to convince casual public transport users to catch a bus or train rather than drive.  The Sydney Alliance is pushing for, amongst other things, all day 15 minute frequencies in Sydney.

So what is the right frequency? 10 minutes? 15 minutes? Again, there’s no correct answer. But as far as frequencies go, I personally am a huge fan of the metrobus network in Sydney. All metrobuses run at 10 minute frequencies during the peaks, every 15 minutes during the day between the peaks, and every 20 minutes during evenings and weekends. It’s KISS – keep it simple stupid. That way you know that no matter where you go in Sydney where metrobuses run, you will know that they run everyday without having to worry about the timetable.

Liverpool T-Way patronage

Patronage on the T-80, a high frequency all day bus route, rose steadily from 60,000 per month when it first began, to 230,000 per month in 2011. Click on image for higher resolution. (Source: STA Annual Report, page 51.)

It is here where the chicken and egg issue comes back. Build a good, frequent, all day service and people will use it. The M10, the first metrobus service to be introduced, today has 187,000 passengers per month, Meanwhile, the T80, which runs all day with better than metrobus frequencies along a dedicated bus only transit way between Parramatta and Liverpool via industrial and low density housing areas, has 230,000 passengers per month (source).

There’s also plenty of low hanging fruit remaining. For example, almost all trains stations West and South of Parramatta do not have 15 minute frequencies all day. Often this is because of half hourly frequencies for a few hours in the middle of the day.

For more on frequencies, check out my other post this week on Transport frequency in Sydney.


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