What are the rules for merging onto a US highway or Interstate from an on/off ramp when the highway is particularly busy? I am driving in Colorado.
This happened to me the other day, the highway was unusually busy and I slowed down to be able to merge with the almost stationary traffic. I was driving at 5-10 mph, waiting for an opening.
Meanwhile, someone pulled out of the highway and zoomed past me on the shoulder at an incredible 20 mph and honked his horn. I didn't want to cause problems for others so I followed him off the ramp and tried the same thing on the next, quieter, on/off ramp.
What do the rules say? Am I right to slow down? If traffic was at a complete standstill and I made it to the end of the ramp with no opening, should I stop and block the ramp, waiting for an opening? Or if things don't line up perfectly, is it my duty to miss my turn in order to aid traffic?
EDIT: This is the kind of ramp I am thinking of, I couldn't think of a better term than on/off but now 'continuous' comes to mind.