Air quality feed locations
The world’s reliance on fossil fuels is slowly changing. In the future, most vehicles will likely be powered by electricity or hydrogen, but right now road transport emissions account for about 12 per cent of global greenhouse gas (GHG) emissions; which are the primary cause of climate change.
It’s why we are vigilant about managing air quality across our motorways as much as we can.
We consistently look for ways to ensure traffic is free flowing in order to minimise air pollution.
In the last financial year, on average, we estimate that our customers saved almost 30 per cent of their fuel use and GHG emissions by choosing our roads over alternative stop-start routes. Customers also save time and have a smoother and safer trip.
Reducing emissions by design
These days when we build a motorway or tunnel we consider the design’s impact on vehicle emissions. For example, the gradient or steepness of the motorway, its alignment and the smoothness of the pavement can go a long way toward reducing vehicle emissions.
We also monitor the local community’s air quality before, during and after construction for any changes.
In Sydney, after opening the WestConnex M4 Tunnels, air quality along busy surface roads such as Parramatta Road improved by more than 10 per cent. The new underground alternative meant a drop in traffic on local streets and less stop-start congestion, reducing emissions in local suburbs. Being one of the cleanest tunnels in Australia of its size, specially designed for low emissions, there has been no worsening of air quality at any monitoring location.
Reducing emissions with traffic management
It’s not only the structure of the road that can reduce emissions, but how a road is managed. Smart roadside technologies such as coordinating the amount of traffic entering the motorway, lane-use management systems that include variable speed limits and information signs that can be activated quickly when needed, CCTV cameras, automatic incident, height and occupancy detection, all work together to help get the best out of a motorway – this includes maintaining free-flowing conditions that help to reduce vehicle emissions.
Managing and reporting air quality
All of our tunnels have ventilation systems that move air into, through and out of the tunnel in a safe and efficient way. A typical ventilation system includes:
- jet fans to control air movement through the tunnel
- ventilation fans to draw air into and out of ventilation outlets
- ventilation outlets to discharge air (sometimes called ‘vent structures’ or ‘stacks’)
Ventilation systems are designed to meet stringent air quality measures, which are reported to and enforced by the relevant environmental authority in each state. We monitor air quality within our tunnels and, depending on the individual tunnel may also monitor ventilation air quality and ambient air quality around tunnel portals.
In Brisbane, we’re using technology to adapt our tunnel ventilation systems to better align with traffic flow and allow air to be released from tunnel portals as well as ventilation outlets during off peak periods. These improvements will reduce energy consumption while allowing us to maintain safe air quality both inside and outside the tunnels.
For more information on how we manage and report on air quality you can download a fact sheet (PDF) or refer to frequently asked questions below.