The unlucky numbers in Lost are 4, 8, 15, 16, 23 and 42 and never really explained. Hurley won the lottery with these numbers, the crazy inmate at the insane asylum repeated them over and over, and the odometer on his car. The total miles on the car were 48,151.6 and the trip odometer was 234.2 miles.
Hurley’s lottery win was followed by bad luck, a house burns, his mother breaks her leg, a plane crashes into the chicken restaurant, and then there is the Lost plane crash.
But in a dream within a dream, the car episode is in the series of concurrent flashbacks to a life after escaping the island and life on the island. The normal literary tool is the flashback, and Lost makes extensive use of the device in earlier episodes to fill in biographical information on the characters.
But the flash forward device becomes an intimate feature of the series in later episodes. The way to explain this is to assume that the current timeline is after the escape, and the flashback part of the story is the time on the island. It’s a little bit of work, but when you see them on the island, you have to assume you are getting filled in on how they escaped, while life in the present is happening after leaving the island. For the second time for some of the characters.
Now it’s getting really hard to keep straight. While we imagine the second return from the island as the present tense, many sequences occur back on the island. But in one sequence, Sayeed is being extradited, back on the plane to return to the island, after working for evil Ben killing people and such. So that scene is a flashbackback. Desmond is the most difficult character to keep track of past, future, present, etc. The mad scientist guy who invented the whole time travel thing is written out of the script fairly abruptly, but does return from time to time.
Desmond first escapes the hatch, the Swan station for the mysterious DHARMA initiative, and we learn that Hurley’s numbers must be typed into the computer every one hour and 48 minutes.