First off NEVER weave through traffic, it's illegal but never enforced, and it's dangerous.
I'm going to say something now that most people will think I'm from another planet, I think most people here already think that anyways! I've been riding for over 40 years, I rode a lot of miles in major cities like Los Angeles BEFORE there were bike lanes, and I rode many miles where there were bike lanes, I've seen and read about a lot of accidents involving motorists and cyclists and I have determined in the last few months that bike lanes are more of a danger to cyclists than without! What? you scream at me! Follow my insanity for a moment.
Before there were bike lanes we all learned taking the lane was safer than riding to the far right unless there was a large shoulder of course but on city streets you don't have shoulders, so lets go where most accidents happen and that's in cities. So we took the lane, this meant that no one was going to cut you off unless they simply want to kill a cyclist that day. However along came a "better" idea and bike lanes were developed and what I observed over the years has begun to trouble me. I have noticed that as you ride in a bike lane cars will aggressively pass you so they can beat you to the intersection or entrance to a shopping center and turn right in front you forcing you to hit the brakes hard or hit the side of the car as they speed off, I've seen cars use that lane as their turn lane, as a place to park forcing you to weave out into traffic in either circumstance, catching motorist off guard and striking cyclists; motorists moving over to use that lane and never looking in their mirrors and sideswipe a cyclist or smash them up against a curb; semi trucks and buses needing and using that bike lane space to make their wide turns and running over cyclists they never saw. I have seen a major uptick in accidents involving cyclists since lanes were installed, and at first, and for many years, I thought I was imagining things, but now with street cameras and after watching many videos of accidents happening to cyclists I have determined that bike lanes are more dangerous than people realize, and much more dangerous than without those lanes.
So I now avoid bike lanes, and I've found myself in much better situation in the terms of safety, sure I may ******** a motorist or two but so what? The only time I will use a lane is if by chance it doesn't have any intersections or shopping center entrances for a few miles, but in cities that would never happen.
Now that I got that off my chest back to your question, if you're at a red light you need to stop and wait for the light to turn green because in most states you have to obey the rules of the road just as car does, some states allow you to run the red but ONLY if it's safe to do so, sort of like being at a stop sign, if you do get hit doing that it's your fault for not proceeding when it was safe to do so. Keeping the car thing in your mind, if your at a red, and the light turns green and there are cars blocking the intersection the safest way to approach that is to WAIT till the traffic moves out of the way and the other cars have stopped and you can proceed without conflicting with traffic, just as you would have to if the same situation occurred while you were in your car, never ever attempt. to weave around the cars unless someday you want to visit the hospital and get a new bike.
YES, must people will block the intersection because they are in a hurry and they think they are the King of the town and their business is more important than anyone else's, so they'll block the intersection so they don't have to wait another turn at the lights. In some cases people don't simply think ahead or the situation occurred to fast for some reason not seen in the line of traffic ahead, and don't realize that the cars are stopping and will unintentionally block the intersection. So in larger cities blocking the intersection is almost par for the course. If you take the lane and find yourself blocking the intersection you need to quickly be thinking, and be thinking ahead at all times, and find the safest escape route so you don't get hit by some jerkwad ****** off at you for blocking the intersection with a lowly bicycle.
At the very least my idea about bike lanes will strike up some interesting conversations, but before you do, settle down a bit, think hard about what I said, study some accident videos, look back on your experiences, and then comment. But I refuse to go to the insane asylum, frontal lobotomy did not work on me the last time they did that to me, nor did shock therapy, it was determined that I was lost cause.
