I understand that it's a good idea keep the local (10-digit) numbers in your phone for the police and fire departments where you live and work. See, for example

I understand that it's a good idea keep the local (10-digit) numbers in your phone for the police and fire departments where you live and work. See, for example the San Francisco PD web site http://www.sf-police.org/index.aspx?page=38 http://www.sf-police.org/index.aspx?page=38 which notes, "When calling 911 on a cellular phone near a highway, the call is connected to The California Highway Patrol (CHP) dispatch center."