Story highlights 30% of wireless 911 calls in San Francisco were accidental, research suggests

Such calls are a hassle for dispatchers, who must try to call back

(CNN) The emergency dispatchers who handle calls to 911 must grapple with urgent situations, frantic callers and garbled messages.

As if that's not enough, now they're facing another challenge: butt dialing.

Accidental calls make up a significant percentage of 911 calls in San Francisco, according to new research by Google that seeks to explain a huge increase in emergency calls in that city. Such calls, typically made when smartphones are in pockets or purses, are placing a strain on already-taxed dispatchers who cannot communicate with the callers and must try to call them back, the report says.

Google researchers shadowed 911 dispatchers in San Francisco and found that 30% of the wireless calls they received during a particular window of time were accidental. This is a time-consuming hassle for dispatchers, who hear an open line and don't know whether the call is a mistake or a legitimate plea for help.

In the vast majority of such cases, the dispatcher had to call back the number to leave a voice mail, which wasted an average of one minute and 14 seconds per call, Google found.

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