High visibility clothing has spread from the work site to the public arena and, as such, has complicated the reasons for hi-viz clothing. However the fundamental underpinning of high-viz is to contrast against the surrounding environment. This contrast does not only relate to clothing but also signage.
Several years ago, a couple of women from Tasmania visited the offices of SafetyAtWorkBlog to discuss the practicality of hi-viz vests for toddlers and small children. The hi-viz logic of the work site is easily applied to the public park or farms. A contrasting colour to the trees or bushland would make it easier to identify someone, like a wayward child. On a work site, the hi-viz is more about identifying a hazard, whether that be a person, an overhead wire or a work boundary.
Occupational health and safety (OHS) law in the United States has little impact on that of any countries outside of North America. But the response to those OHS laws by US and multinational companies indicates corporate approaches to workplace safety and this can spread round the world. The anticipated strategy to worker safety under the Presidency of Donald Trump is expected to be harsh, if he attends to it at all.