Glo-Toobs are very nice.
They are quite handy for signaling a bus. It's easy to miss someone standing in the dark with a black down jacket. A little blinky light also alerts other drivers so they don’t run you over in the darkness. Get a green one and put it on the strobe setting. Reds, blues and whites look like brake/headlights. All the bus drivers liked them.
I have the blinky kind and they are far superior to the krill lights. The Glo-Toobs are smaller and much brighter. And they work in the icy cold. I tried both but the Glo-Toob easily won. The krill uses a more common battery though.
Inova also makes a handy signaling light called the 24/7 but the Glo-Toob is smaller.
My other choice to signal the bus was an official U.S Airforce rescue beeper/stobe.
Not an super survival item, but I gotta get to work.