It sounds like you came up I-25 and took E-470, the toll road shortcut to eastbound I-70. It has express toll so no booths needed. Folks without an express toll RFID gizmo get the plates read and a bill is sent in the mail. The big green sign for the exit does say it is a toll road.
Please do not confuse Denver with Colorado. Us natives don't like Denver either, even those of us who live here.
I’m visiting my brother in Denver at the end of the month. Can you recommend a few places where conservatives go. Thinking beer and steaks I believe he lives near Commons Park