The tram line has been open for about two years now, but people still have trouble remembering the tram has the right of way. Maybe this will help, the audible warning doesn't seem to be enough since many people have headphones (understandable, noise cancelling is a must if the city has any car traffic).
I saw a bunch of projected signs like this in Finland that were used for marking bike paths. Projections mean that the markings are still visible even in thick snow (I saw a few people cycling through knee deep snow. Finns are absolute madlads, even by Nordic standards). They're useful because even when paths are cleared (which was impressively thorough — the vast majority of paths had been ploughed)
Stuff like this is why I love travelling — I'd have never thought of the issue that regular snow would cause for road markings, nor would I have thought to solve it like this.