Sitting through traffic on a Friday is no fun. Depending on where you live, though, it could either be a minor headache, or a traumatic event on par with heading to the airport the day before Thanksgiving. The Washington Post recently mapped out just how far you can get out of town on a Friday afternoon in major American cities in just one hour.

The Post’s Sahil Chinoy used traffic information culled from cell phones and car sensors by the location data company Here Technologies to map out travel times from downtown neighborhoods at 4 p.m., 7 p.m., and 10 p.m., showing how car travel varies by city and time on a Friday night. (They’re all estimates based on July 28 data.)

Sahil Chinoy // The Washington Post

Unsurprisingly, considering geography and city culture, the answer can vary a lot. Compare Southern California and Northern California, for instance. In L.A., well-known for its horrendous traffic, an hour can’t even get you through the county. You’ll be able to travel 25 miles in that time period, at best—probably while suffering through that weird phenomenon where all the cars on the road slow down for seemingly no reason. But in Sacramento, you speed through up to 50 miles at rush hour. (You can get more than 50 miles from Las Vegas, too, but it’ll mostly land you in the middle of the desert.)

Some cities remain active long into the night, too, while others empty out right after the workday ends. In New York City, you can’t even get past the New Jersey suburbs at 4 p.m., and that doesn't change much as the night goes on. In most other cities, though, there's much less traffic by 10 p.m. compared to the late afternoon and evening. In Boston, for instance, you can travel 25 miles farther if you leave at 10 p.m. compared to leaving at 4 p.m.

The map shows what you probably already expected: In cities that were built around the car, it is, for the most part, easier to get out of town. Older cities on the East Coast like Philadelphia or Baltimore have tiny one-hour radiuses, while cities in Texas and the Midwest are easier to navigate behind the wheel.

Geography matters a lot, too. Cities that are built around water tend to be harder to escape from, like San Francisco, Seattle, and New York. If you only have a few bridges that lead out of town, they’re going to get clogged with traffic, while a city with several large highway arteries can move more people. Miami is virtually impossible to travel from because the city is wedged between the ocean and the Everglades.

That traffic time does more than just eat into your weekend plans. It’s really bad for your health. You’re essentially stewing in emissions, and long commutes on a regular basis are associated with stress, high blood pressure, and obesity. That may be fine if you’re trying to get out of the city for a weekend in the country every once in a while, but if you’re just trying to get home on a Friday night, that’s a different story.

For a closer look at the data and how it varies based on the time of day, see Chinoy’s graphics at The Washington Post.