(US) Traffic entering expressway from onramp: right of way?

on the expressway. that's why many ramps include a yield sign or something similar.

in some states, like Kentucky, if you are on the expressway and you have noone in the lane next to you you are required to move over and allow the traffic to enter, which is a decent courtesy in any state, but either way, the expressway traffic has the right of way.

The traffic entering. The traffic on the expressway should move over to the left lane so the inbound traffic can merge. Otherwise the inbound traffic will have to STOP in order to find a way in.

The inbound traffic does NOT have a STOP sign. There is not even a YIELD sign. They can't come to a complete stop and then speed up to 55 mph.

The traffic already on the highway, should merge over to the left lane.

Or there should be a really long MERGING LANE built in, so inbound traffic can pick up speed and be allowed to merge.

Expressway traffic has the right of way.

The people on the expressway will always have the right of way, you are coming into oncoming traffic so you must yield..

traffic already on the expressway. it is a courtsey if a driver is able and does move left one lane to help you in , it is not mandatory that they move left. you should be up to expressway speed when you merge<

Traffic. Anyone entering traffic from any direction must be ready to yield.