The farther out into rural areas you get, the longer the response times. In big cities the response time is seldom less than 10 minutes, but as you get into the suburbs it stretches to 20, and beyond the suburbs, where you might have a local sherriff's department with only a few deputies covering a rather large swath of farm country... well, fortunately, places like that tend have far lower crime rates and higher per-capita firearm ownership, so it balances out.