A figure has been doing the rounds: "$6.2 billion bill from diesel trucks and buses strengthens the case for an electric switch." It's been republished across dozens of outlets, almost word for word, all crediting the Electric Vehicle Council.

What's real: the number comes from a genuine piece of work, a University of Melbourne discussion paper estimating the annual taxpayer cost of health impacts linked to nitrogen oxide emissions from trucks and buses over 4.5 tonnes.

What the headline leaves out: it's a discussion paper, not peer-reviewed. The authors themselves call for more research before the figure is relied on. Its release lined up with a live Federal Government policy reform. And the scope is specifically heavy trucks and buses over 4.5 tonnes, not diesel generally.

The bottom line: a real cost estimate exists and deserves genuine attention. But "here's an early estimate that needs more research" and "this settles the case for electrification" are two different claims.