Sydney’s anti-litter signs that read “Don’t be a tosser” are also worth mentioning in this context.

India has some great ones: https://www.wanderlust.co.uk/content/9-funny-indian-road-sig...

I wonder how "Follow traffic rules and avoid blood pools" would fly in the US...

When I first moved to New Mexico, I was puzzled by the billboards which featured a stern cop and the word "ENDWI". What the hell's an endwi? Eventually I realized it was just the (weird) slogan from the state anti-drunk driving (Driving While Intoxicated) campaign.

The NM signs I love are the ones that say "Gusty Winds May Exist."

Indeed.

In Aus I liked the roadsigns with random trivia questions along the really straight part of the road from Bundaberg to Brisbane, trying to keep your mind occupied so that you stay awake.