"For emergency responders, cell site information alone is generally of little value in finding the victim or 9-1-1 caller, since the the geographic area served by each cell site can be very large," Crombach wrote in a letter to Acting FCC Chairwoman Mignon Clyburn.
The group studied millions of calls in Bakersfield, Pasadena, San Francisco, San Jose and Ventura County. Only 20 percent of calls in San Francisco and 27 percent of calls in Pasadena included the precise location of the caller, according to the study.
The industry drop-off in location data was driven by declines in information provided for AT&T and T-Mobile calls. Location delivery for other carriers stayed mostly steady since 2008.
AT&T provided precise location information for 20 percent of calls, and T-Mobile provided the information for only 10 percent of calls.
“The safety of our customers is a top priority for AT&T and we are thoroughly reviewing CALNENA’s filing,” an AT&T spokesman said. T-Mobile declined to comment.
It is unclear why the carriers provided less exact information in recent years.
An FCC spokesman said the agency is reviewing the filing.
The FCC enacted rules in 2001 that encourage carriers to forward the estimated location of outdoor 911 cellphone callers to emergency dispatchers. If that fails, they are required to identify the cell tower that the phone connected to.
In the letter, CalNENA urged the FCC to toughen its 911 location requirements.
"This is a serious public safety concern and a significant stress on our public safety assets, both the dispatchers and first responders who have to spend considerable time obtaining the location of wireless 9-1-1 callers," Crombach wrote.