Interstate highways are funded by the federal government. The states oversee their construction and maintaince using flow-through federal money.

If I have that figured out correctly, then all Interstate highways should be equal. They're not.

On a recent trip through Tennessee, Alabama, Mississippi, Georgia and Louisiana, I observed vast differences. I think the states rank somewhat like this:
Tennessee - best
Georgia
Alabama
Mississippi
Louisiana - worst
I crossed Louisiana from east to west almost to Texas and then came back the other way. I-10 was mostly concrete with jarring expansion joints and painful bumps. There were crews out applying asphalt over the concrete and completed sections were some relief, but in a relatively short time, I expect the shifting concrete underneath will break up the asphalt.

I observed the same conditions to a lesser degree in Alabama and Mississippi on I-59. Traffic was light, so I think drivers were taking a longer but smoother route to avoid the uncomfortable roads.

There was a vast improvement at the
Georgia line and things got still better in Tennessee.

But why, with similar funding, aren't these highways closer to equal from state to state?