When I first moved to Seattle in the early 2000's I remember seeing signs on I-5 with a number to report people violating the HOV lanes. Call '764-HERO'. A local band started called '764-HERO' and I thought that was so clever given that only local people would get the joke.

In Australia there are signs along the highway that say things like "Drowsy Drivers Die" and "Rest/Revive/Survive."

Got my attention.

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.

Now there are slogans like "Drive. Text. Die." They still haven't found a slogan/campaing to get people to put their phones down that has been as effective as "Don't Mess With Texas". Sometimes, no matter how much you wish it so, a slogan just won't take off.

Ouch. So close to the double entendre “Litter Hurts”. Should just leave it at that and play games with if nature and $$$ signs.

"Litter and your wallet will hurt" makes more sense but it is perhaps too wordy.