Here we have bicycle lanes that double as parking lanes (annoying as hell) and when a car is parked you have about two feet between the door and the next lane on the road. Less if the driver is a tard and doesn't know how to park.
If I see a driver's or passenger's head through the rear window I slow way down and will wait for cars to pass before taking the lane.
At electric bike speeds, you can't be sticking your head back all the time to look for cars, it hurts the neck, affects your steering and takes your attention off stuff ahead.
I use a mirror like this one to help facilitate lane changes:
http://www.amazon.com/Mirrycle-MTB-Mountain-Bicycle-Mirror/dp/B0009R96YK/ref=sr_1_1
(This is my third one, I have smashed the other two by letting the bike fall over on uneven ground. Grr..)
I don't believe it is legal to lane split in most areas, trying to hug the curb or get around tightly packed cars like in that video is a recipe for disaster.
I'm not so worried about cars in close curb riding, but all the crap that accumulates next to it, like old construction materials, garbage, bottles and car parts.
Or the occasional sewer grate that grabs your tire.
So when there isn't a distinct bike lane I will sometimes take the whole lane and sit in traffic, while contemplating another route. Yes, the drivers of the cars behind you looked pissed when they first roll up, and some honk, but a middle finger and a quick throttle jab on the green is all it takes to shut them up.
There are also bike friendly intersections which have green space in between where the cars are supposed to stop and where the pedestrians cross, you can roll past stopped cars, get in front of them and be the first to go through lights. This is especially useful if you have something that can accelerate faster than cars.
When all else fails, pedaling slowly on the sidewalk is an option (it is legal here on SOME kinds of sidewalks but not all), especially when construction messes with your lane. I have done that a few times, and as long as you have a good reason for riding on the sidewalk the authorities won't bother you. Not wanting to get killed/doored by cars and/or construction is a perfectly good reason.