On July 29, 2008 at 11:42 am, there was a minor earthquake in Chino Hills, California, 35 miles east of Los Angeles. Though it measured only 5.4 on the Richter scale, and caused virtually no damage, cell phones in the greater LA area were inoperable for upwards of five hours following the shake.
Why? Because millions of people tried to get in touch with their families, friends, and loved ones all at the same time, making it impossible for anyone to connect . Citizens returned to their regular routines within minutes of the quake, but the lines were still so jammed as to render all cell phones completely useless for the better part of the day.
It stands to reason that when zombies begin roaming the streets, cellular phone service will instantly become a thing of the past, a distant memory of more peaceful days gone by. Unless both you and your desired party have predetermined alternative forms of communications – landlines, two-way radios, etc. – anyone out of earshot might as well be dead.
So take heed. The terror of being isolated from your fellow man, and surrounded by relentless, hungry zombies is not reserved for a lonely rural farmhouse. Faced with the threat of the undead, a city of twelve million can quickly become as desolate and unfamiliar as the dark side of the moon.