How Long Until ‘The Walking Dead’ Runs Out Of Gas?

The survivors of The Walking Dead have been living in an apocalyptic hell for just over 600 days.

That’s right: it hasn’t even been two years since small town cop Rick Grimes woke up in a world gone bye, in an episode that first aired in 2010.

Since then, Rick has established himself as leader of a tight-knit group of survivors, Team Family, who found a home in Virginia’s walled-off Alexandria community.

Team Family has trekked on foot as well by vehicle — including a gas-guzzling RV, RIP — and they’ve been warring with Negan and his army of Saviors, whose seemingly endless resources include a cache of vehicles of all sizes, including trucks and jeeps.

Where’s all that gas coming from, and how long until it all runs out?

Many survivors would have raided gas stations and fuel suppliers in the earliest stages of the initial outbreak, making fuel even more of a commodity.

Using a ratio supplied by The Walking Dead creator Robert Kirkman in issue #10 of the comic book — the ratio of walkers to humans is 5,000 to one — SourceFedNERD‘s Matt Lieberman estimated 0.0002% of the world’s population, or just 1.4 million people, were still alive when the outbreak went global.

In the 600+ days since the outbreak, even more people have died, dwindling those numbers even further: Lieberman estimated there were less than 400,000 survivors in the entire world.

Roadways in The Walking Dead are littered with discarded vehicles, and with much of the world turned and/or turned into cannibalistic corpses, there’s not much competition to siphon off the gas literally laying around.

As pointed out by LiveScience, the lifespan of fuel varies: energy consultant and “Handbook of Petroleum Refining” author James Speight says it’s “very difficult to generalize,” saying gasoline can keep for months to years, taking into account environmental factors like heat, oxygen and humidity.

The Walking Dead‘s Georgia (and now Virginia) setting would mean a lot of gas sitting out in the muggy heat, but it doesn’t seem to affect our survivors any: they regularly travel in vehicles, sometimes entire fleets of them, and no attention is ever paid to so much as the possibility of exhausting a supply.

“If you leave gasoline by itself, over time … it just doesn’t perform the way you think it’s going to perform,” said former chemical engineer Richard Stanley, who explained lighter hydrocarbons start to evaporate out of inactive gasoline.

The fuel can evaporate and begin oxidizing away, particularly if exposed to, say, the world of The Walking Dead, where a lot of it would be resting in cars constantly exposed to the elements.

Much like the issue surrounding trimmed grass — viewers sometimes question how a world enduring an apocalypse maintains fresh lawns — the simple answer is that it’s not pertinent to the show. The survivors use gas because they do, much like how the grass stays trim: it’s likely an intentionally overlooked detail that isn’t worth exploring.

Still, former showrunner Scott M. Gimple did say he was working on a story about the grass, making it possible for The Walking Dead to explore the survivors’ fuel supply in a future plot point.

The Walking Dead resumes its eighth season Sunday, February 25 on AMC.