Law enforcement agencies will soon have access to the Commercial Mobile Alert System (CMAS), a voluntary emergency alerting system developed by the Federal Emergency Management Agency (FEMA), the FCC, and wireless carriers. This emergency messaging system will offer agencies another tool to broadcast alerts to the public.

The system is designed to push messages of 90 characters or less out to cell phones that are communicating with a cell tower. If your phone is active on a wireless network, then the CMAS messages will be sent to it. A complete breakdown of how the system works can be found on the FEMA Website.

The system is especially appealing because the alerts are geographically based, so the messages can get to the right people at the right time. People don't have to sign up for it, it goes to any cell phone communicating with a cell tower, and it's free. The system is voluntary for wireless carriers to implement, so it may not have widespread availability at first.

In order to appreciate the value of a wireless messaging system like CMAS, you have to first look at the recent history of violent events in the country and how wireless messaging would have helped the community.

Five years ago an active shooter at Virginia Tech killed 32 people. Investigations of that atrocity brought to light a shortcoming in the emergency communication system of the campus and every other community in the country. Almost all of the messaging systems in place at the time were based on obsolete hard-wired phone lines. Unfortunately, hardly any of the students still used land lines.

The Virginia Tech shooting taught public safety agencies that they needed to get messages to people’s cell phones. But there simply weren't any viable options for doing so.

Five years ago, the options for wireless emergency messaging were scarce and costly. Most agencies to this day continue to rely on Reverse 911 to alert a neighborhood to an emergency situation. Reverse 911 can be a highly effective way to get information directly to a targeted community, but it doesn't guarantee that people are actually getting the emergency message in a timely manner. It only works when the messages are being delivered to an occupied home. Anyone who has used Reverse 911 will tell you that it is fairly common to have the system leave an emergency message on a home answering machine, only to have the message heard hours after the situation has been resolved.

Over the past five years, emergency messaging businesses have popped up promising public safety agencies a direct wireless link to the citizens. However, these services cost money and rely on an overburdened communications infrastructure. Most agencies do not have any budget for this type of service, so they are not widely used.

Social sites like Twitter offer short messaging capabilities and options to have messages sent to a user's text-enabled cell phone. Some public safety agencies use these sites for community messaging, but they are not the best option for targeting a specific neighborhood.

A similar service called Nixle was introduced specifically for public safety agencies and schools, but it requires residents to sign up for the service, something that most people don't want to do.

Internet-based messaging is a valuable tool for community messaging, but it has pitfalls. The messages are not going over a secure network and are only getting to people that sign up for the service.

CMAS is certainly an idea that is long overdue but many questions about this system need to be answered. And if it is like the Amber Alert systems, there may be built-in shortcomings. A municipal agency cannot issue an Amber Alert on its own. It must go through a larger government entity to verify whether the message fits the criteria. This is a necessary process to avoid abuse of the system, but it can cause delays. We don't know how easy it will be for agencies to send an emergency alert through CMAS. It's safe to say that if the process is too complicated, it won't get much use.

The best practice may still be a shotgun approach to getting information out to your community. Each agency should evaluate the technology, define the needs of its community, and use the systems that work best for everyone.

Mark Clark is a 27-year veteran police sergeant. He has served as public information officer, training officer, and as supervisor for various detective and patrol squads.