Riding bicycle on the road
When riding bicycle on the road, you have to be bold enough to ride in the center of your lane, so that the vehicle behind you has to make proper lane chance to pass you. A lot of drivers don't know they should share the road with bicycle, so they always want to squeeze into the same lane with you. That is extremely dangeous for both the driver, and you. Especially you, since you are unprotected on bicycle. DMV should declare driver licenses of those drivers void, so that they have this great opportunity to read the Driver's Handbook again. When I say "those drivers", I include both the drivers that actually do so, and the drivers that want to do so.
In same roads, the right lane is wider, and it is good enough to fit in one vehicle and a bicycle. Like in this satelite image:
But, (yes, there is a "but"), if there is a vehicle parked in front of you in the same lane, like the two white cars in the upper right corner, you should reconsider.
When bicycling, lane changing and rejoining the traffic require high skill and more coordination of your body. When maintaining your bicycle running, you have to look back to the traffic, to see if there is a car comming. When your are commuting, there is always car comming, and they are driving at higher speed than you. It's barely possible to find enough room for you to merge into the lane, so your best bet is that you have half of the room, and the car behind you is nice enough to slow down for you to merge in. So you need to look back to check for enough room, then stick your left hand straight out to signal, while still riding the bike with only your right hand on the bar, and be ware of the parked vehicle in fron of you.
So if you are not sure about rejoining the traffice later, my suggestion is to stay on the center of the lane, to let the drivers figure out how to pass your safely.
The other thing that the drivers don't honor is the bicycle stopping room.