I would think a possibility is that it's from a dataset where the data wasn't recorded properly so they are unsure as to whether it was am or pm but didn't want to throw out the data point.
It means the bus comes at the same time am and pm.
It doesn't. It means AM but it's not the bus driver's bedtime yet so it's not really morning. But your misunderstanding is valid because this is a goofy way of communicating this information.
AM radio, FM radio, PM radio, XM radio...
XM would be space-based transmissions on the X-band.
It's mostly Howard Stern.
eXtreme meridian!
All I can think of is "oh Jesus not another way to handle time..."
WHHYYYYY would you run a table like this? 12 minute cycles are just insane, and they're obiously "maxed out" for rushhour, but that's when those times are least realistic. Just run it every 15 minutes the whole day, and tone it down to every 20 at night.
Is this "crappy"? I'd assume it's meant to indicate "next day". In 24 hour time systems, you might see 25:00, 26:00 etc to do the same.
I have never in my life seen anyone write the next day as e.g. 25:00.
It would be rather something like 1:00+1 or whatever.
https://peraperayume.blogspot.com/2016/09/overnight-hours-in-japan-2500-2600-2700.html?m=1
Now you have.
I would think a possibility is that it's from a dataset where the data wasn't recorded properly so they are unsure as to whether it was am or pm but didn't want to throw out the data point.
It means the bus comes at the same time am and pm.
It doesn't. It means AM but it's not the bus driver's bedtime yet so it's not really morning. But your misunderstanding is valid because this is a goofy way of communicating this information.