They're called Mansfield bars in the US, named after the actress Jane Mansfield who died after colliding with a trailer. They're not required federally and not particularly effective as they're generally not inspected or maintained.
It's bonkers that the US named them but don't require them. They're called Mansfield Bars in the UK too, presumably because there isn't really a better or more descriptive name you can give them.
There's probably an "official" name in some dusty Ministry of Transport document like "side protection collision bar" or some such, and TÜV probably calls it something like "Seitenaufprallschutzgerätüberlaufschutzausrüstung" or some damn thing.
Oh, looks like I got that wrong. Rear bars are required, but the US standards are well lower than the Canadian ones and periodic inspection isn't required.
