The number that usually only goes up went down: road-traffic deaths fell 21 percent worldwide between 2011 and 2025, according to a WHO report published July 20 [1]. Over the same years, more than a billion additional motor vehicles rolled onto the world's roads [1].

More cars, fewer deaths, is not the natural order of things - it is the result of specific choices [1]. Lower speed limits, seatbelt and helmet laws, safer road design, better trauma care: each shaves a share off the toll, and together they bent a global curve that a billion new vehicles should have pushed the other way.

The WHO European Region led the way with a 36 percent drop [1]. The global annual toll is still large - about 1.16 million people - which is why the report pairs the good news with a push for more [1].

'This progress shows that change is possible when countries invest in safe road systems,' said WHO Director-General Dr Tedros Adhanom Ghebreyesus [1]. The win is exactly that: proof that a number treated as fixed is not, and that ordinary policy saved a fifth of the lives it used to cost.