Review of Greenhouse Gas emissions estimates for Westconnex Stage 2 New M5 EIS

Dr Owen Price, South Sydney Greens and Senior Research Fellow, University of Wollongong.

The EIS for stage 2 of the Westconnex motorway attempts to calculate future emissions from the construction and operation of the road and from the vehicles that will use it. The construction phase causes a large one-off Greenhouse Gas emissions (473,000 tons), but the vehicles using the road will generate the most emissions (~7 m tons/yr). The calculations for the construction and operation (14,000 tons/yr) seem reasonable. However, the EIS predicts that by 2031, Greenhouse Gas (GhG) emissions from road use will decrease by 229,000 t/yr compared to a scenario based on doing minimal road works (2.9% decrease) and this prediction is flawed. The calculation takes several factors into account: the general projected growth of road traffic across Sydney; the likely preferences of road users to change their current routes to use the new toll; the reduction in congestion from adding new capacity and induced travel (the tendency for more journeys to be undertaken just because of the increased ease of travel).

The calculation of a Greenhouse Gas saving is based on three basic deceits: 1) it conceals the predicted actual change in GHG emission (27% increase over 10 years); 2) there is a huge underestimation of the induced travel effect); and 3) the comparison with a do-minimum scenario is a false comparison.

  1. Actual 27% increase in emissions. The modelling predicts an actual 27% increase in GHG emissions between 2021 and 2031 with the project (though there are no statistics to compare with current emissions). This is completely incompatible with Australia’s commitment to reduce GHG emissions by 28% by 2030 or with the agreements reached at the Paris Conference to be carbon neutral by 2050. We need to be moving rapidly to reduce road travel which is inefficient. For example, road haulage emits three times more GHG than rail for the same tonnage. The presentation of the EIS, focussing on the purported saving compared to a do-minimum scenario is deeply dishonest in that it conceals the dramatic increase in emissions that will occur under this project, as well as under the do-minimum scenario.
  2. False comparison. The EIS compares GhG emissions from traffic to a scenario without major road works. Considering that billions of dollars of public money is being spent on the project, the proper comparison should be with one where that money is invested in an alternative project that delivers a reduction in road use (and hence emissions). The predictions assume that road traffic will be about 107,000 journeys per day in each direction in 2021 and 130,000 by 2031. As an alternative, a bi-directional light or heavy rail line could reduce this by as much as 40%, providing a much larger reduction in GhG emissions.
  3. Induced travel. There is a basic understanding in transport economics that if you add capacity on a congested road network, the number of vehicles using the network will increase until the congestion returns. While the EIS acknowledges such an “induced travel” effect, there is no explanation in the 258 page transport report about what assumptions were used. The report seems to have hugely underestimated the effect, as can be seen in some of the predicted traffic volumes. For example, it predicts if that all of Westconnex is built, traffic flows in the project area will be reduced by 10% and on the Pacific Highway around the Cook River by 70% compared to the do-nothing scenario. This conclusion must be based on some childishly naive assumptions. In reality, users of these roads will adjust to any new ease of movement by increasing journeys. The main reason that the EIS predicts a reduction in GHG emissions is that there will be less congestion, based on these predictions of relatively low-flow. But, if the full effect of induced travel is taken into account, the level of congestion will be the same in 2031 as it is now, and there will be more vehicles affected. Thus, instead of a decrease of 2.9% compared to the do-nothing scenario, a 20-30% increase is more likely.




One thought on “Review of Greenhouse Gas emissions estimates for Westconnex Stage 2 New M5 EIS

  1. The increase in greenhouse gases due to the building and operation of WestConnex is outrageous given our stated national commitment to reducing Australia’s already significant contribution.


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