A reader of the blog pointed me to some Sankey diagrams available on the U.S. Department of Transport (DOT) Federal Highway Administration (FHWA) website. Sankey arrows are shown as a U.S. map overlay.


The first transport Sankey diagram shows the net tons of goods being transported on flatcars (either as trailer-on-flatcar, or container-on-flatcar) on the U.S. railway systems. The transport volume quantities are clustered into four groups shown with four different arrow widths. It is nice to see how in the eastern part you still have many railroad tracks, but with significantly less transport on them, while to the west coast you basically have 3 main lines, two of which carry more than 25 mio tons of freight per year.

The second one represents freight transport on railroad (bright red), inland waterways (blue) and national highways (dark red). Values also in million tons per year. I am not sure whether flows are to scale, or if transport quantities are also clustered into groups as in the first diagram. I can distinguish at least five different arrow magnitudes, even though only three sizes are given in the legend. A great transport Sankey diagram, as it shows that the East has most of the cargo, and has a much denser transport infrastructure. The reason why railroad transport on this second Sankey diagram differs so much from what is shown the first one, is probably due to the transport of bulk materials not shown in the intermodal transport quantity map.

Flows are not directional in both diagrams, so I assume that quantities for both directions have simply been added.

Can anybody confirm that the massive stream out of Wyoming by rail is coal?

Colm from carbontracking.com in a comment to this blog post on Energy Flows in Ireland pointed me to an updated version of this Sankey diagram for 2007.

Sustainable Energy Ireland has published the report “Energy Ireland – Key Statistics 2008”.

This is the updated overall energy flow Sankey diagram from the report.

And here is another interesting one from the same report. It features the fuels used for transportation in Ireland with a breakdown by vehicle type.

All flows are in ktoe (1000 tonnes of oil equivalent, 1 ktoe = 41868 GJ). The flows seem to be mostly to scale, although there must be a problem with the flow ‘Refining Losses 6 ktoe’ which seems wider than the ‘Rail 47 ktoe’ flow, for example. Private cars consume most energy of all vehicle types (2184 out of 5685 ktoe or 38.4 %) , followed by trucks (road freight) and airplanes.

I won’t be commenting on the 3D design of the Sankey diagrams, which is definitely … eye-catching. Colm asked which software has been used to create these, but another reader had already pointed out in a comment that it is based on SankeyHelper, but has undergone retouching in Illustrator.