What is the cost of commuting by car compared to public transport?

Weekly cost of commuting per household by car and public transport, Melbourne (Data from BITRE)

The exhibit shows that in terms of weekly household cash outlays, commuting by public transport is vastly cheaper than commuting by car, irrespective of where the commuter lives (see first three rows).

Both fixed and variable costs are much higher for cars than for public transport. For example, outer suburban households where the workers drive spend $302 p.w. compared to $41 p.w. for households whose workers use public transport.

The real killer for cars is fixed costs such as depreciation, interest and registration. These dominate variable costs like petrol, servicing and parking.

The numbers are taken from this report (which I’ve mentioned a few times recently) by the Bureau of Infrastructure, Transport and Regional Economics (BITRE). The Bureau looked at the journey-to- work costs a household of two adults and two children aged under 18 years face in Melbourne, and how they vary by location and mode.

Location is an important variable – BITRE assumes household income, level of car ownership and commuting distance/time vary substantially by location (measured here as inner city, middle suburban and outer suburban). It’s assumed households who drive own a new 4 cylinder Camry. BITRE only counts that proportion of car standing costs attributable to commuting.

Although public transport costs considerably less in terms of cash outlays, the exhibit also shows commuting by public transport takes much more time than commuting by car, no matter where a household lives. The extra time is enormous for households living in the middle and outer suburbs i.e. for more than 90% of Melburnians.

For example, the cumulative weekly commuting time for the workers in an outer suburban household who use public transport is 1,326 minutes, whereas workers in neighbouring households who drive only expend 561 minutes per week. Even members of inner city households who use public transport spend more time commuting than members of outer suburban households who drive.

BITRE value the opportunity cost of time spent commuting at average weekly earnings (just over $800 p.w.). With this assumption it’s evident time is far and away the main cost of commuting by public transport, even for households who live in the inner city. That’s a key reason why many argue the focus of public transport spending should be on improving services, not lowering or abolishing fares.

Still, notwithstanding the significant time penalty associated with public transport in Melbourne, it costs inner city and middle suburban households significantly less in total to commute by public transport than by car. Even in the outer suburbs where public transport is at its worst, the total cost on average is pretty much the same according to BITRE.

So why is public transport’s share of work journeys only 24% in the inner city, around 15% in the middle suburbs and below 10% in the outer suburbs?

That’s a good question and I think it could point to a major limitation of BITRE’s analysis – the Bureau doesn’t explain the underlying travel pattern that its analysis is based on. The reader understandably assumes commuters have a choice between two modes for the same trips, but what I suspect the numbers in the exhibit are really showing is the existing pattern of accessibility to employment in Melbourne. And that varies greatly by mode.

At present, public transport users can only comfortably get to a limited number of Melbourne’s jobs, mostly in the CBD and near-CBD. Existing public transport use reflects that limitation – most trips are CBD commutes. However given that a little over 80% of jobs are outside Melbourne City Council’s boundary and relatively dispersed – indeed, 50% are more 13 km from the CBD – most jobs are more easily accessed by car-based commuters.

So BITRE’s figures seem very limited in their application and should be interpreted with that caveat in mind. Having said that, I have some issues with the methodology anyway. Read the rest of this entry »

How much time do Melburnians spend commuting?

Average one-way commute distances and times, Melbourne (data from BITRE, 2011)

On average, workers who live in the outer suburbs commute 2.5 times further to get to work one-way than their counterparts who live in the inner city. That’s in terms of distance – probably no surprises there. However what’s not always appreciated is the extra time they spend commuting isn’t that much more – only 19% more than inner city commuters.

Since fewer than 10% of Melbourne’s workers live in the inner city (approx 5 km radius around the Melbourne Town Hall), what’s more pertinent is the average commute times of the more than 90% who live in the middle and outer suburbs. Their commutes don’t vary much – the average middle ring worker commutes for 36 minutes, the average outer suburban worker for 38 minutes. That’s just 5% more.

There’s not even a lot of variability within the suburbs either. Outer-West commuters average 42 minutes – the longest of any sub region – while the shortest commutes are enjoyed by workers resident in the Middle-North and Middle-East sub regions, who average 36 minutes. Only six minutes less.

This data is taken from Research Report 125 recently released by the Bureau of Transport, Infrastructure and Regional Economics (BITRE) – see exhibit. BITRE largely relied on data from the Vic Department of Transport’s VISTA survey. See also my earlier post on changes in commuting distances over 2001-06 (unfortunately BITRE doesn’t analyse the trend in commuting time).

The spatial regularity in the time workers devote to commuting is consistent with the idea that, on average, travellers budget a relatively fixed amount of time for travel (see here for more on travel budgets). Workers living in the inner city spend almost as much time travelling shorter distances than suburban workers because the former travel at considerably slower speeds, reflecting high levels of traffic congestion in the inner city, higher use of public transport and more walking and cycling.

At the metropolitan level, 40% of workers spend less than 30 minutes getting to work one-way and 61% less than 40 minutes. However there’s a tail of long distance commuters – 17% spend more than an hour commuting one-way. I don’t have data on this 17%, but since the average commute by public transport in Melbourne takes almost twice as long as the average car commute, I suspect many of them are train travellers (I hope to get some data on this).

The numbers in the exhibit are the result of a long-standing trend – improvements in transport infrastructure lead to higher speeds, giving residents the opportunity to increase the distance between work and home but still get there in much the same travelling time. Residents may either move house or move job, or both. This happens with both private and public transport improvements.

So the ‘headline’ implication is that, in general, improvements to infrastructure will very probably result in people travelling further to work. Where that is primarily by car it’s likely, given the technology of the existing vehicle fleet, to lead to higher resource use, more traffic congestion and make greater demands on the environment. There might be exceptions, but in general that’s what we should expect, especially given that all modes are under-priced. It’s worth noting that jobs also move outwards. Read the rest of this entry »