Cars that are stopped at the end of the slow traffic could turn on their
emergency flashers briefly to warn others approaching the situation. While they
shouldn't have to, I practice doing that and I'd rather use my
flashers for a few seconds than to be reear-ended by someone now realizing
traffic has stopped or nearly stopped. After a few seconds there's more
cars stopped behind you and you can cancel using the flashers.
Excessive speed, no seat belt and not paying attention...... all the
ingredients for a deadly accident... slow down and use your seat belt.