Is the vest-in-cars rule EU wide?
AFAIK the vest in cars thing is French, but that has become irrelevant.
The yellow vest (gilet jaune) has become a symbol of resistance against the all-powerful state, and those attempting to control the entire dialogue.
Dunno. Unless somebody is selling them in other places (now at a quicker pace).
In Germany, the required vests can apparently be yellow, orange, or red. They apparently were first required in 2014.
In other news, I just noticed that Egypt has banned the sale of the vests.
In good fashion it's up to each EU country. This is a summary for UK drivers going to Europe -
https://www.theaa.com/european-breakdown-cover/driving-in-europe/what-do-i-need
PDF list is half way down
If they made the rules to common it would put each country's transportation ministry out of business. This is one of the fallacies for the EU becoming a ‘cost saving’ through integration...:^)