Every year on Yom Hashoa (and Yom Hazikaron) they sound an air raid alarm across the country for two minutes of silence in order to reflect on the tragedy. It is absolutely awe inspiring to witness. Here is a great Youtube video showing the Tel Aviv highway shutdown completely.
I haven't been all over Israel and I've heard some places are less machmir about this, but in Tel Aviv it is absolutely amazing. (I saw it for the first time in person last year).
It is like the ultimate freeze.
I think Israel really does an excellent job trying to take these days seriously. They also make sure that ALL stores - restaurants, grocery, etc... - are closed by 7 PM on these days.