The biggest thing I encounter is people thinking I'm a pedal only bicycle, then pulling out in front of me. So I use my horn to get them to look directly at me. This generally causes them to hesitate just long enough to realize I'm going a lot faster than they thought I was.
Yes that's a serious hazzard of riding on the shoulder or in the bike lane. You really gotta be on defense
The lights on my Whizzer make's me look like a small M/C which greatly helps in the day or night
At night I'm lit up like a Rainbow Disco Ball that helps too