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 »

How much time do Melburnians spend commuting?

Posted: November 13, 2011 | Author: | Filed under: Transport - general | Tags: , , , , | 10 Comments

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 »