Mode split for commutes to centres of major cities, 2011 (source: Charting Transport)

It was only a matter of time before the Prime Minister’s sojourn in Western Sydney produced an ill-advised infrastructure proposal like the execrable Cash for Clunkers program promised at the last election.

Ms Gillard is offering to provide $1 billion to NSW Premier Barry O’Farrell for the WestConnex motorway on condition it connects to the city centre, to Port Botany, and doesn’t involve tolling roads that are currently free.

She seems to be keeping up with the Opposition Leader, Tony Abbot, who promised $1.5 billion for the project in January, also contingent on a link to the CBD. He said WestConnex is still evolving:

but we’ll ensure there’s an expressway-standard road from the west to the city as part of our commitment. It has to be in there.

Yesterday Mr Abbott reiterated his offer is conditional on WestConnex linking to the CBD (contrary to some reports, it appears it’s Ms Gillard keeping up with Mr Abbott on this one, not the other way around).

This idea is even worse than Cash for Clunkers. At least that copy of President Obama’s original program got the objective right (lower emissions) – it just got the means laughably and cynically wrong.

The last thing Sydney needs is a new major road to the centre. As Barry O’Farrell pointed out to the two leaders, it would cost much more than they’re offering – probably in the region of $5-$8 billion.

The very point of it is doubful too, because very few residents of Western Sydney work in the CBD. According to a study by the Urban Research Centre at UWS based on 2006 Census data, just 6.6% of workers living in Greater Western Sydney commute to the centre.

That suggests the proposed road might not be the best or most cost-effective way the government could help residents of the region.

Another relevant point is the CBD is already highly accessible from Western Sydney and the rest of the metropolitan area by public transport.

The CBD is a transit-based agglomeration, not a road-based agglomeration. It’s the most public transport-rich location in the metropolitan area by an order of magnitude.

At the 2011 Census, just 17.4% of commuters to the CBD came by car, a considerable decrease on 20.4% in 2006 (see exhibit, via Charting Transport).

Public transport’s share, on the other hand, went up from 72.8% to 74.4%. The proportion of workers who commuted by cycling or walking also increased over the period, from 6.5% to 7.9%.

Even the chief executive of toll-road operator Transurban thinks the CBD road link is a bad idea. He told the Sydney Morning Herald:

Public transport is really the most efficient way to deliver people into the CBD.

The amenity of the CBD has been despoiled by cars and buses, weakening its role in tourism and as an attractive working and living environment for knowledge industries like finance and media.

The objective should be to reduce the number of cars (and buses) that come into the centre, not increase it.

The NSW Government’s promised Eastern Suburbs Light Rail service, which will eliminate 180 buses in the busiest hour, is the appropriate direction for policy.

Better public transport is also a more sensible way of improving mobility in Western Sydney than building the proposed motorway. There are other shortfalls in services in the region too, e.g. in education and health.

Even more troubling is the kybosh the Prime Minister put on tolling existing roads. That’s poured cold water on the prospects for road pricing more generally across the entire country.

No doubt it’s difficult politically, but one way western Sydney could get a substantial improvement in mobility in the short to medium term would be via some form of congestion charging.

If road space were priced properly (not exactly the same as tolling) the need for many new roads would evaporate or be delayed for many years.

I don’t reject outright the idea that in some circumstances a new road might be appropriate, for example to serve dispersed suburban jobs (I’ve noted before Sydney’s CBD only has 12% of metropolitan jobs). However the CBD is the last place where a new road would make sense.

This week’s focus on Western Sydney has also seen some wild numbers quoted in the media about the state of transport in the region.

I heard one news report claim the average commute in the region is one hour and another state that some residents commute for “up to” four hours!

Fortunately, the Urban Research Centre at UWS has analysed the journey to work numbers from the 2006 Census for the Greater Western Sydney region.

The Centre estimates the average one-way journey to work duration is 30.8 minutes and 37% of trips take less than 20 minutes. To put that in perspective, I noted the other day that the average journey to work duration in Melbourne is 36 minutes and in the outer suburbs it’s 38 minutes.

Almost a quarter of commutes in Greater Western Sydney take over 50 minutes, although only 3.6% of these were to the city centre. That’s the upper measure of the data, so I can’t say how many take “up to” four hours.

The average commute distance is 17.8 km. Given the small proportion of workers who commute to the transit-oriented CBD, it’s not surprising that overall 77% of workers in the region commute by car.