I see this happen to semi trucks on the highway. People interpret big open space as a place to merge. As you say, people have no consideration for why there might be a large space in front of a semi. A 50k lb+ truck hitting the back of a ~4k lb vehicle is not pretty.

See for a truck it could say "DEATH ZONE KEEP CLEAR" which would be accurate. Given that it's projected it could rotate through various languages too.