Writing about a tour bus breaking down on my fictional band, I couldn’t think for a moment the name for hazard lights. It occurred to me just as I prepared to ask Google. My fingers finished typing before I could stop them.
As a result I found an informative article. In the United States, not every region treats driving with hazard lights the same. I lucked out in Ohio, my instincts proving correct. Here it is legal to turn them on when driving in bad weather or through an emergency situation (i.e. you spot debris on the road).
For other in the USA, here is the article if you want to reference a quick guide to state laws (be aware the information was last updated in 2013):
Do you ever find yourself needing hazard lights? Is it legal where you live, in the USA or elsewhere?