How do Runway markings work?

Why are the runway numbers numbered like this? Aren’t they all go in the same direction? So why is there 8L, 8R, 9L, 9R, 10?

But DFW has 36C and not Heartsfield I would greatly appreciate it if someone can answer this question since I am super confused🤔🤔

I’m not sure exactly but I would assume that 9L and 9R were built together, and then 10 was built later. They can’t call 10 9R at that point bc 9R already exists so they would rather just call it 10 so they don’t need to repaint 9R.

Edit, quick visit to wikipedia confirms this.


OK makes sense I did not know if the runway was off by a little bit. Because it is quite weird how that is set up.

I believe all 5 of them are the same heading. YYZ has the same thing where I believe 24L/R were built first but when 23 was constructed they couldn’t name it 24R bc that would involve repainting 24R as 24C, just easier to use another number

Edit: YYZ actually had 23 first but same deal they didn’t want to repaint it as 23R when the other two got built.

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Makes sense I should probably ask my dad and he works at the airport. And probably knows more than me.

He says it could be because there are planes taking off and landing simultaneously unparallel runways so they marked them different numbers he said he’s not too sure as well and did not know how to explain it good may be someone that works for ATC will now

I hope you’re joking because Hartsfield has been 5 runway for like 15 years.


oh i am thinking of something else, it was something involving 10-28 but nvm

Don’t take my word for this, but I think I heard somewhere that if there’s multiple runways with the same heading, they can either do Left, Center, or Right, or if there’s more than 3 parallel runways, they can just do one heading up or down for the other runways.

That makes sense because more than 3 runways

Runway 36C has a runway heading of 360°, that’s why the runway is 36C/R/L.

Atlanta doesn’t have a runway that has a heading of 360°. As you may notice, ATL runways face east & west. As opposed to DFW, who runways are facing north & south.

Oh I never thought about that. Thank you for clearing that up for me.

The way runways are numbered is based on their magnetic heading. Then if there are parallel runways they are given the Right, Left, and Center designations. After that they will give them the number one off. At that point though it does start to become a bit of a judgment call and what makes the most sense for that airports operations.

At DFW you have 6 parallel runways, which means it nicely divides by the 3 L/R/C designations into two sets, 35 and 36 one each side of the main terminal area.

At Atlanta it looks like they just decided that the best course of action was to have an 8 pair, a 9 pair, and then 10 off on it’s own. You can see I’m sure how that would be beneficial to operations over 8L and 8C over at one side then 8R next to 9L which is far away from 9R for example. At this point runway number being exactly the same as heading doesn’t matter so much. It’s good to have it similar so you can have an idea of what runway they will be using based on winds and stuff, but simplicity in operations and communications is much more important at an airport like ATL.

Or just watch this video that gives an extremely drawn-out and detailed explanation

Thank you that video really helped I always saw that video on my YouTube, but I never thought to watch it. Thank you for letting me know.😀

The video is funny Lol

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