There are channels you should program in your radio for emergencies. I have only used them a few times, but it comes in handy. These are for reference, and specifically for HAM radio 2m and 70cm, there may be some variances. CB channels are preprogrammed, so you just have to use one of those channels for assistance. Here is the list for HAM, GMRS, and CB.
- HAM 2m National Simplex Frequency – 146.520MHz
- HAM 70cm National Simplex Frequency – 446.000MHz
- GMRS Simplex Travel Frequency – 462.675MHz
- GMRS National Repeater travel Frequency – 467.675MHz
- CB Channels 9, 19 (North/Southbound travel), 17 (East/Westbound travel)
You should also program HAM or GMRS Repeaters in areas you will be traveling into your radio. This will allow you to reach people over repeaters in the event of an emergency, and no one is listening on the frequencies above.