Why is the ride so bumpy on I-5 (and other concrete highways)

I’ve always wondered why the ride is so bumpy on concrete highways around here. The specific bumpiness I’m thinking about is where you are stuck in a jam going 20/30mph, there’s some “ka-chonk ka-chonk” that occurs and rocks the vehicle that you don’t necessarily feel at 60mph.

I used to chalk it to the how worn I-5 is, but then when the SR-99 tunnel opened a few years ago, I did also notice that the ride sucked in a similar way even though it was brand new.

What gives? Is there an engineering/design reason?

Highways (re-)surfaced with black asphalt don’t do this and as soon as much more comfortable (and quiet…)