Are public transport trips longer (than car trips)?

Posted: November 28, 2011 | Author: | Filed under: Public transport | Tags: , , , , | 6 Comments

Non-work trip distances (km) by car and public transport (%) - data from VISTA

I’ve frequently mentioned that trips by public transport in Melbourne are longer on average than those by car. The exhibit above illustrates that difference using data from the Department of Transport’s VISTA data base.

It shows the length of non-work trips in Melbourne by private vehicles versus public transport. For all practical purposes, it’s cars on the one hand (in red), versus trains, trams and buses combined on the other (in blue).

A ‘trip’ refers to travel between main activities. Where multiple modes are used on one trip a single ‘main mode’ is defined. For example, if a person drives from home to the station, catches a train to the city, and walks to their destination, their mode for the trip is the train.

It’s important to get these figures in perspective from the outset. There are almost fourteen times as many non-work trips made by car as are made by public transport. This reflects the dominance of private transport in Melbourne.

It’s evident from the exhibit non-workcar trips are substantially shorter – just compare the two fitted curves. In fact 56% are less than 5 km, whereas the corresponding figure for public transport is 27%. At the other end of the scale, 5% of non-work car trips are longer than 30 km, compared to 9% of public transport trips.

Work trips (i.e. commutes) tend to be longer than non-work trips in the case of both private and public transport, but again public transport trips are longer on average. For example, 40% of commutes by public transport exceed 20 km. The corresponding proportion for car commutes is much lower, at 27%.

I’ve shown non-work trips in the exhibit because they account for around four fifths of all trips (defined as per above). They are not as dominant in the case of public transport, but still comprise two thirds of all trips by trains, trams and buses.

Trains are the key reason public transport trips are so much longer – people travel considerably further on metropolitan trains on average than they do on buses and trams. I don’t have data to hand that separates out trains (I hope to get my hands on it shortly), but the difference between cars and trains would be much more dramatic.

It’s not that the train out-competes the car for long trips. In fact many more people still prefer to use the car for long trips than take any form of public transport. For example, while 7% of non-work car trips are over 25 km compared to 14% of public transport trips (they’re virtually all train), the car trips number 534,000 per day. The comparable number of trips made by public transport passengers is just 80,000.

Rather, people who choose to travel by train are more inclined to use it for longer distances, on average, than car travellers. I’d say that’s largely because Melbourne’s train system is designed to transport people across long distances – primarily from the suburbs to the city centre.

Cars are flexible and in non-congested conditions can get travellers to a range of dispersed destinations, both near and far. Melbourne’s train system on the other hand is relatively inflexible by comparison. It essentially leads to one destination. Read the rest of this entry »

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

Posted: November 14, 2011 | Author: | Filed under: Transport - general | Tags: , , , , | 7 Comments

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 »