What you are observing is the trick the industry used to get approval for changing LED billboards— they “donate” say fifteen hours per month to public service announcements. This kind of concession is gold to an ambitious public servant, the old prohibitions never stood a chance. The PSA could be “stop electronic billboards” but that was the way they got through high-friction public processes.

Good org on the other side of the issue: Scenic America: https://www.scenic.org/why-scenic-conservation/billboards-an...

My state has a neat legal trick that applies to most major highways: You can set up a big tall sign to advertise but it has to be for a product or service drivers can stop and buy on the premises.

This removes much of the incentive for spamming enormous signs and renting them out to the highest bidder. That may change if it becomes really cheap to put a functional vending machine below.

I saw many billboard ads on Portugal (Europe) highways. As a Canadian, it seemed like a lot.

Europe has billboards too. Perhaps not everywhere, and not as bad as some other places, but it does exist, and it is infuriating. I don't think I've seen them flash intentionally, but nobody seems to be too interested in fixing broken LED bulbs.

I even saw a "you should be looking at the road" ad on one of those billboards.

Honestly. Premier Ford you listening?

As someone who is not Canadian, pretty much the only thing I know about Doug Ford is how actively against road safety Doug Ford is.

https://en.wikipedia.org/wiki/Doug_Ford#Bike_infrastructure