BITRE's freight vehicle telematics data project collects truck vehicle movement data from millions of actual truck journeys to better understand how and when congestion affects heavy vehicle operators.

This can help governments and industry plan industry, trip times and locations.

One thing this data lets us do is see the potential range of a freight vehicle leaving a certain locations and how this range changes over the course of a day. This story illustrates this with something called isochrones.

This is an isochrone. It shows the approximate area a pedestrian, starting at Sydney's Circular Quay, could reach in 10 minutes. It is, understandably, restricted largely to the immediate vicinity.

Now we overlay the 20 minute isochrone which covers most of the CBD.

And finally the 30 minute iscchrone which extends across the Harbour Bridge.

Pedestrian ischrones are relatively simple since walking speed is relatively constant. It is largely unaffected by the time of day or by the type of roads used.

Freight vehicles are more complicated. Congestion varies over the day with traffic and this changes the speed that can be travelled in certain directions. Different road classes also mean some directions can be travelled more quickly than others.

We can explore this with 2022 data.

This is the 30 minute isochrone for a freight vehicle leaving Port Botany at 4 am.

This is when the potential area reached is the greatest it will be during the day and it covers over 500 square kilometres.

It approaches major centres like Parramatta and Chatswood and even reaching the South Western outskirts of the metro area.

But at 9am this has shrunk to less than 400 square kilometres.

Whilst the reach to the West and South have only been mildly affected increased commuter flows towards the city have restricted the area that can be reached on the major roads, such as South Dowling Street, that are shared with them.

The North Shore is barely reachable and Parramatta is no longer approached.

From here on we will continue showing the isochrones of congested times in red and less congested times in blue . You can also use a mouseover on the graph too see the sizes at other times of day, including for 10 and 20 minute iscochrones.

The lowest reachable extent is in the afternoon peak at 5pm. Congestion moving away from the city, especially on the M5 Motorway, severely restricts how far a freight vehicle can move West and South.

The 30 minute isochrone at this time is little over half of what it was at 4am.

By 7pm the the area has expanded again, although it is still smaller than it was at 3am.

Let's compare this with a location less close to the CBD. This is Chullora, a major and centrally located logistics location. At its peak extent, at 5am, the 30 minute isochrone covers nearly 1 200 square kilometres.

You may also note this area is much larger than that reachable from Port Botany, well over double. This pattern will repeat itself. Ports are necessarily bounded by water, and in many cities are located on narrow points of land that limit routes in and out.

There is a contraction to 900 square kilometres in the morning peak, mainly in the north and east.

But again the lowest extent is in the afternoon peak with under 70 square kilometres. Althought we are further away from the CBD the afternoon contraction is still mainly t0 the West, caused by delays on the M4 and M5 motorways.

Here

And here

Let's look at the Port of Melbourne. At its greatest extent, at 4am, the isochrone covers over 1 600 square kilometres. It extends to the North and West peripheries of the urban area and towards Dandenong in the South West.

This contracts to around 1 300 square kilometres in the Morning peak at 9am

And to less than 900 square kilometres in the Afternoon peak.

This pattern is familiar from Sydney. There is a long decline from the largest extent in the early hours to a minimum in the afternoon when commuters are leaving the city.

However where the geography of Sydney meant the contraction was not equal in all directions we can see a fairly even contraction from Port Melbourne along all outgoing motorways.

On the Eastern Freeway

And on the Western Freeway

If we move towards the fringes the now familiar pattern changes.

This is Laverton, which includes many light industrial areas and is close to the Western Ring Road. Unlike the relatively steady decline towards 5pm we see in the prior three examples, Laverton has two distinct contractions.

Firstly, however, here is 5am, with a 30 minute isochrone of over 1 300 square kilometres covering the South West of Melbourne as well as large amounts of the North and Inner South East.

By 8am only 900 sqaure kilometres are reachable. This contraction is largely in the East; Congestion on the Western Ring Road and around the West Gate Bridge limits how much of the North and South East freight vehicles can access in 30 minutes.

There is less congestion during the day, but by 4pm the 30 minute isochrome is back around 900 square kilometres. But it is not the same 900 square kilometres as at 8am.

The South East is now partially accessible again.

But the North West is less so..

Moving North, The Port of Brisbane is similar to the ports in Melbourne and Sydney. The reachable area declines from the early hours toa minimum at the afternoon peak. Here is the largest extent of the 30 minute isochrone at 2 am covering 760 square kilometres.

600 square kilometres at 8am

And a big drop to 400 square kilometres at 4pm.

The contraction is paricularly noticeable in the South, around the intersections of the Pacific Motorway, Gateway Motorway and M3.

But a site at the logistics centre of Crestmead looks a bit different. The largest extent is still in the early hours (1 650 square kilometres at 3 am) when the reachable area goes to the CBD and to Ipswitch.

But this site's lowest extent is in the morning peak at 1 107 square kilometres. Commuter flows towards the CBD limit freight vehicles' ability to reach much of the inner urban area, or to move through it to Ipswitch.

There's still an afternoon peak, but the 30 minute isochrone now again reaches the southern parts of the CBD. On the other hand commuter traffic on the M2 means Ipswitch is still not reachable.

This increase in area occurs at the same point that the decrease in the Port of Brisbane Isochrone occurred, around the intersections of the Pacific Motorway, Gateway Motorway and M3. .

On the other side of the country, the Port of Fremantle does not follow the usual pattern. At 1 am the 30 minute iscochrone is over 500 square kilometres.

At 8 am it is just over 300 square kilometres, and has contracted evenly (except, of course, where bounded by the ocean).

The reachable area remains largely unchanged at 5pm, and there are no major changes to the shape.

This differs to Central Cockburn, a logitistic centre accross the river. At 3am the 30 minute isochrone is nearly 1 700 square kilometres.

At 8 am, it has shrunk to just under 1 200 square kilometres.

In particular areas around and North of Stirling, reached by the Kwinana and Mitchell Freeways, are no longer accessible.

After increasing during the middle of the day there is another contraction at 4pm. Compared to the morning peak, areas around Stirling are more reachable.

But Southbound traffic on the Kwinana Freeway means this extra area is largely matched by contractions in the South, towards Rockingham.