Now that Season 1 is over (man, that finale...), I think there's no harm in picking apart components of the story we may have missed before. If the actual game writers want to come in and directly answer questions about the story (like they did on that drugstore helicopter crash post), I see no harm in that either. Until that happens, feel free to muse and agree with or argue against me on my guesses, but please try to provide some sort of evidence from the game.
Anyway, I want to bring up something I noticed about Episode 1 watching other peoples' play-throughs on YouTube. If you choose to tell Clementine that “something else” (walkers) killed Sandra before you did, she says she “heard her scream two nights ago.” (http://www.youtube.com/watch?v=QEO7qcYM-2Y&list=PL3dRLd_mppZFUBBNsObNf0dsc6Cy_FSZ3&index=2, at 9:52)
Let's assume that Sandra died the night of the date of the outbreak. If Lee was in the car crash on the day of the outbreak, he has to have been passed out for the rest of that day, that night, the next day, the next night, and the first part of the day he woke up on. I'm no expert, but that seems like a LONG time to be out cold...
Some people on these forums have suggested that the outbreak started days before Lee was being driven to prison. That doesn't make any sense; if that was the case, the old cop wouldn't be so nonchalant about everything coming through his radio, and the dispatcher on the police radio wouldn't refer to whatever violence started happening in Atlanta as a “riot in progress.” The order and closeness of the messages coming through the radio (first a 10-91E (“animal” bite according to http://www.policecodes.net/ten-codes/10-91e) in the area, then a medical team on it's way to Hartsfield with 10s and 20s coming in (which I assume is a police term for serious injuries), and then a riot in progress with 217s (assault with intent to murder according to http://en.wikipedia.org/wiki/Police_code#The_Hundred_Code) directed towards all officers), suggests that local law enforcement had no clue what was going on and had to deal with multiple outbreaks all of a sudden. You can hear all of this in http://www.youtube.com/watch?v=hDcXIIwTdkE, with the first blurb at 1:50, the second at 2:15, and the third at 2:50. Sorry if some of them are hard to hear.
Depending on how much time you look around in the car for and what you say, the spacing between a single other police car being seen on the highway, and a helicopter and SWAT team making their way towards the city, is only a few minutes. Whatever made people come back after dying and started the whole epidemic must have happened only a few minutes, or couple of hours at most, before Lee's conversation with the cop in the car. A few fatal heart attacks and car crashes later, you have walkers ready to kill (or at least bite) and turn people all over Georgia, the United States, and maybe even the world, depending on whether the phenomenon had to spread or happened everywhere at once.
If, then, the 'apocalypse' started when (or just before) Lee was in the car, and Sandra was half-eaten by walkers that night, and a day and a night later Lee meets Clementine, logically, he had to be out for two days.
The only thing weird about this is that the cop is attacked by walkers and doesn't turn until Lee goes up to him. Which means that either he was also passed out for at least a day, or he took a couple of days to turn (which doesn't make any sense).
Thoughts? Is there something obvious I'm missing? And how does Lee seem to know how long he was out for when he says “two nights ago? Yeah, that's probably what happened”? And how come the answering machine doesn't give a date, even when the first two calls are supposed to be from the day before? Okay, I'm done now.