FRS radios: my understanding is that many jurisdictions are starting to standardize on channel 9 as an emergency channel.

Citizens Band radio may also be an option in some areas.

Amateur radio: The tech licence is relatively simple to test for and handheld radios are getting better and cheaper.

You can also use your flashlight for signaling, and you should carry a whistle as well.

http://www.equipped.org/signal.htm