I've known for awhile that the Missouri cell phone emergency number was *55, but since I've never had to use it, I don't actually know if that means that my phone can call it (I have a Missouri area code), or whether that means that it works in Missouri. I still don't actually know, but I found this site today: Mobile Emergency Numbers, and it says that in Kansas you can dial *HP for the Kansas Highway Patrol, or *KTA while on the turnpike.

This page indicates that *55 is actually the number to dial on a cell phone if you want to reach the Missouri Highway Patrol, not an emergency number in general. It also says that *47 reaches the Kansas State Police.

Here's another list of emergency numbers across the country.

It's all very confusing.