“Zero Hour” isn’t when the zombie apocalypse descends, at least not according to AAA Mid-Atlantic, which is in the business of predicting the exact times of the Thanksgiving traffic apocalypse.

AAA partnered with data company INRIX to analyze holiday travel patterns. The forecast: for travelers on the outer loop of the Capitol Beltway, the rush hour on the evening before Thanksgiving is the absolute worst time to travel.

Vehicles going clockwise will crawl down to 7 miles an hour–roughly the same rate as a pretty good runner–around 5:30 p.m. (hence “Zero Hour”). For those going counter-clockwise on the Beltway’s outer loop, the nadir is around 6:15 p.m. on Tuesday, when traffic slows down to around 23 miles per hour.

Trying to take 1-95? Your worst bet is on Thanksgiving afternoon itself, when the highway is at its slowest around 1:15 p.m. I-270 and US-50 are also at their most congested on Wednesday afternoon.

AAA estimates that there will be around 1.2 million people on the roads trying to get to their own turkey-filled festivities.

“Travel delays will become a contagion on area freeways and highways on the Tuesday before Thanksgiving and on Thanksgiving Eve, as virtually everyone experiences a significant increase in travel times and traffic congestion,” John B. Townsend II, AAA Mid-Atlantic’s Manager of Public and Government Affairs, said in a release. “Holiday traffic, and any poor soul caught up in it, will creep, crawl and slither along. Given this, holiday travelers will be forced to add ‘extra buffer time’ to their trips to reach their Thanksgiving destinations on time.”

Google doesn’t break its data out by specific location, but the company indicates that Wednesday around 3 p.m. is generally the busiest time to be on the D.C. area’s roadways to leave for Thanksgiving. As for the return trip, the company says that 3 p.m. Sunday will see the most traffic.

So if not Tuesday and Wednesday afternoon, what are the best times to leave that aren’t the middle of the night? Google suggests 6 a.m. on Wednesday morning.

INRIX also analyzed the area’s roads and made predictions about where the most bottlenecks will appear. The area around Exit 126 on 1-95 South is at the top of the list. If you’re traveling in Virginia, you can also check out historic trends by time of day for specific roadways.

“Through-travelers along the I-95 Corridor account for ‘30 to 40 percent of Beltway traffic each day.’ Their numbers will swell that day and during those hours. That’s bad news, as area residents heading home from work and school converge with holiday travelers heading out of town and holiday road-trippers, [and] as delays and congestion peak,” AAA said in a release. “Collectively, Washington area residents and motorists will once again experience the hell that is Washington metro area holiday travel traffic.”

So, yeah, good luck with that.