Cellphone 911 Is Crappy At Locating You

If you’re calling 911 from your house, use your land-line. If you don’t have one, be prepared to give your address or location to the 911 operator. Why? From USA Today:

Owing to limitations in Emergency-911 technology, the dispatcher probably won’t be able to pinpoint your location. Unless you can get to a pay phone — not an option in this case — you’ll probably have to give the dispatcher detailed information about your location so emergency personnel can find you.

“Just because you dial 911 on your cellphone, the call-taker doesn’t necessarily know where you are,” warns Bob Gurss, director of legal and government affairs for the Association of Public-Safety Communications Officials (APCO.)

How well 911 locating works depends on what type of cell phone you have and where you are.

There are two types of systems for wireless 911 access: network-based and GPS (Global Positioning System). Network-based systems use multiple cell sites to get a fix on a caller’s location. GPS systems work off chips in cellphones and determine location from a constellation of low-orbiting satellites. Both have pluses and minuses.

Network-based systems tend to work better in urban areas where cell sites are plentiful. They are less reliable in rural areas, where one site may cover many square miles.

GPS is the opposite. Because it relies on satellite signals, it can be highly accurate in open areas. But it’s less reliable in urban settings where buildings and other structures can block satellite signals. Weather also can be an issue.

Verizon Wireless, which uses GPS, “works dead-on” in rural areas, says spokesman Jim Gerace.

“But if you’re (calling 911) indoors, we suggest customers get close to the window” to improve GPS performance, says Fran Malnati, an executive director.

In short:

Cingular and Tmobile: Good in cities. Bad in rural areas. Really bad. Possibly only able to “pinpoint” you within a 5 mile radius.
Verizon and Everyone Else: Good in the middle of nowhere or outside. Bad in cities.

FCC Chairman Kevin Martin is in favor of tightening the rules about how wireless companies are required to report their 911 performance. Currently, they only have to calculate their coverage on a nationwide basis and will not share statistics about local performance. —MEGHANN MARCO

Growing wireless use highlights limitations of 911 [USAToday]