A popular conception of public transport is it’s used primarily by two groups – CBD commuters and the disadvantaged. For example, in the preamble to a new survey it’s done on public transport use, the Australian Bureau of Statistics (ABS) emphasises the contribution public transport makes to agglomeration economies in the CBD. 

Exhibit: Adult public transport users and non-users (‘motorists’) by household income quintiles in Melbourne (each series adds to 100%). Source: data from ABS

It also says:

Public transport can positively influence the social outcomes in a city for people most at risk of social isolation — low-income earners, the unemployed, the elderly and people with a disability by providing easier access to employment, education, and health and community services

The ABS asked adult residents of Melbourne about their use of public transport. As I noted last week, How important is public transport?, it shows 38% of all adults said they had used it at least once in the last month (I call this group ‘public transport users’).

The survey doesn’t tell us about the purpose of trips so we can’t tell how many users are commuters. However it does throw light on who uses public transport according to location, income, age and employment status.

It’s clear geography matters. While 38% of all adults in Melbourne are public transport users, that rises to 57% of inner and middle suburban residents (Zone 1 in the fare structure). The corresponding figure for outer suburban residents (Zone 2) is only 29%.

I expect that’s largely because Melbourne’s public transport system is radial, with services converging on the city centre i.e. service density is higher closer to the centre (depending on the direction, Zone 1 extends 11-18 km from the CBD). However public transport is still just as important in the outer suburbs as it is closer to the centre.

Because there are twice as many people living in Zone 2 as Zone 1, the former actually has slightly more public transport users in absolute terms – 609,000 versus 589,000. It’s a misconception that public transport is a benefit enjoyed only by those living close to the centre.

Income also matters for public transport. Adults in the top household income quintile make up 29% of all public transport users but 21% of all motorists. This bias is all down to inner-middle suburban residents.

Top earners constitute a staggering 38% of all public transport users in Zone 1 and 28% of motorists. In Zone 2, however, the relative proportions are much the same – 20% vs 19%.

What’s interesting is there are more top quintile earners in absolute terms living in Zone 2 than in Zone 1. Yet the number of top earners using public transport in Zone 1 is almost double the number in Zone 2.

It could be that if you’re a top earner living in the inner-middle suburbs, there’s a good chance you’ll work in the city centre. Because of traffic congestion and high parking charges, you’ll be more inclined to use public transport.

If you live in the outer suburbs and earn at the top rate, you’re more likely to work in the suburbs. You’ll tend to drive because in the great majority of cases it will be faster than public transport.

Age is another key definer of public transport use for adults. Travellers aged 18-34 years make up 46% of all public transport users in Melbourne, but just 28% of all motorists. Conversely, only 24% of those aged 55 years or more use public transport, compared to 32% of motorists.

What’s notable in this case is there isn’t a lot of variation by Zone. Younger adults are over-represented on public transport and older adults under-represented irrespective of how far they live from the city centre.

The ABS is right to say in its preamble that unemployed workers use public transport. They make up 6% of all public transport users but 3% of motorists. In fact a larger number of unemployed workers use public transport than don’t (44,000 vs 40,000).

So there are some groups who are over-represented among public transport users. I think it’s important though to be wary of characterising or stereotyping public transport as the mode of a particular group.

There are still large numbers of adults in other categories who use it, even if as a group they’re under-represented. For example, there are 643,000 public transport users who’re aged 35 years or older – that’s more than the 551,000 aged 18-34 years. And as I noted above, more outer suburban residents use public transport than inner-middle suburban residents.