If you live in Los Angeles County you may be able to send a text to 911 when there is an emergency. The new service is being rolled out and it's already available in 170 communities including Long Beach and Glendale. If the message does not go through, the FCC requires all U.S. phone carriers to send a note to the customer saying the text failed. One significant limitation: It's not available during roaming and only texts using written English are accepted.
For a list of which communities in LA offer the service, click here.