[michaelrpeskin]

Learned to drive (a long time ago) in PA and now live in CO. You’re right it’s all weird.

In PA, red arrow is just a regular red light that happens to be in a turn-only lane. All laws are the same as normal red light, the lane marking restrict your movement.

In CO, red arrow means stop and no turn on red regardless of lane markings.

Just about all traffic control laws are standardized federally except lights. That feels like the most important one to reduce confusion.