I know I've seen signs that indicate that a particular right turn lane is only for cars turning right, busses and bikes, but is this a general rule in Chicago? There is such a sign going eastbound on Howard, crossing Clark.
I've seen bike lanes end at right turn lanes, and when they do, the stripe for the right turn lane begins right smackdab in the middle of the bike lane.
If I were to be going straight, what would be the leeeeegal thing to do? I use the leftmost portion of the right turn lane and scoot up to the front of the motorized pack.
Having a hard time sifting through google searches. Maybe I'm not using the right words.
I doubt there are laws with wording specific to a bike lane fade-out point.
Standard laws, in their ambiguous glory, take over; legally you're entitled to take the lane that's most appropriate for the direction you're traveling, while staying as far to the right as practicable per state law, and yielding to all other traffic per Chicago ordinance.
If it is safe, go ahead and get in front of the cars. As far as being to the right or left of the lane, I always pick the lane that has the most room. This sometimes means I have to weave between cars because they don't know how to follow each other in a straight line. Just beware that if this isn't a "turn only lane" the cars you pass might not be looking for you on the left side.
I think what you're describing is both legal and also the safest thing to do, and if you're approaching the intersection while the light is green and you can feel that bus/car behind you, take the full lane.
There's no sign, but a good example of where that's critical is northbound on Elston as you cross Ashland. I actually take the full lane that's one over from what is technically the right-turn only lane, as FAR too many drivers don't realize until the last second that they aren't in the right turn lane, yet they turn anyway. I'll happily take a ticket and my 5 minutes to raise hell in court over getting flattened.
In general, I try to keep in mind that a driver's "blind spot" is approximately 3 to 6 o'clock from the driver's perspective. So you definitely do not either want to enter that zone, nor to allow a car to get ahead of you with the same result - that's what may lead to someone trying to turn right directly in front of (or into) you.