My 17 recommendations for sharing lanes. (I said recommendations, not rules!)
1. If traffic is moving at or near the limit, don't share.
2. Keep your speed in line with the traffic you moving through, not too fast.
3. Stay in one lane, don't weave in and out. (that is not sharing)
4. If you have flashers, use them, or flick your high beams occasionally to alert drivers you're there. In the daytime I sometimes keep my high beam on.
5. make sure you can see the rear view mirrors of the vehicles as you approach them. If you can see their mirrors, they have a bettter chance of seeing you.
6. Be VERY cautious when passing gaps in traffic, many drivers are "hole divers" and just move over without warning or necessity.
7. Watch the inside front wheels/tires of the vehicles as you move through traffic. When you see a tire turn in towards you, that's a sign they are changing lanes.
8. Don't assume that cars will use turn indicators, most don't care.
9. Toot your horn politely if someone is blocking your way. Be nice and wave them a little "thank you"after they let you pass.
10. If safe, make a polite thankyou wave after passing people. Even if it pisses them off that your sharing, they'll think it was their idea of you thank them. It is also good diplomacy for all of us.
11. Do not encourage or engage in any competitive road behavior while commuting, it only makes it harder for the rest of us who share lanes daily.
12 At night, be EXTRA cautious if you share, headlights all look the same in a rear view mirror. If you can avoid sharing at night, then don't risk it.
13. Driver's body language can tip off a lane change as well. Watch for head checking, or nervous head stuff(looking around quickly etc.)
14. Be mindful of your "6", behind you could be another rider or something else you need to be aware of.
15. Stay alert, if you get tired from too much alertness, take a break off the highway or fall back into traffic.
16. Use your signals! When you begin to share or when you get back in to a full lane. The more noticeable you are the better.
People appreciate knowing what are intentions are, as much as we appreciate knowing theirs.
17. Remember the basics of the CA Rider's Handbook and try to stay within the guidelines. Sharing is not allowed in most places (other states) and many of us depend on sharing to get places before we are 106 years old. If there is ever a law passed to ban sharing, the rest of us will lay the blame on the assholes who ruined it for everyone else. We will hunt you down and fart in your faces, or worse.
I think it is important to practice courtesy when sharing, eventually drivers will be de-sensitized and maybe even just accept that it's a fact of driving in California. They might even get to like it , knowing we will get to work or wherever way before them.....(ok, that's a lie)