Well, if we must follow stereotypical protocol, then anything that makes noise should do the trick, that or use the cripple that is slowing you down as bait.
Fire crackers, those deafening emergency alarms women carry around, pull the pin, compact, you can fit it in your bag. I probably wouldn't recommend shooting if you are trying to evade, that would attract attention your way, unless you are aiming at an explosive substance, which IF you succeed to ignite it with a bullet, it should get the zeds attention, but everything seems easier in movies...
Unless I meet a zombie I can't tell you for sure what will or will not work...^_^
bottle rockets, cheap, effective, simple to use, store, ect. if they are illegal in your state, then I would go with a magnesium firestarter, grind some magnesium down, put it in a piece of paper with some fuse in it, light it, it's insanely bright and hot.
Siblings make the Best bait! But man I sure do miss my brother right now.
Its good to be funny in a dark situation hahaha
Ikea sells cheap alarm clocks for 99 cents I think, uses 1 AAA battery, time can be set and makes a loud alarm. it could be rigged to go off X amount of seconds after throwing. and it's all digital, so there's no mechanical parts to break! they're small too, sold as a "travel" alarm clock. of course, they're function clocks too. they may be made of cheap flimsy plastic but it's rugged enough for regular use.