A hi viz vest does not increase your visibility. If it did, 2 vehicle (or more) motorcycle accident stats would be dropping, not rising. There is nothing you can do to make other road users "see" you.
Other road users need to be trained, not threatened with legislation, fines, or billboards, and taught about the things they need to look for. Until that is done you need to take FULL responsibility for avoiding issues on the road. What you wear has little to do with whether you will be seen or not.
How many people here had a driving instructor teach them things like, "If a ball rolls out of a driveway either stop or reduce your speed dramatically because 9 times out of 10 there's a kid following"?
I'd venture that common sense nuggets of information like that have evaporated in the face of needing specific information to pass a scratchy test.
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