When the Buffer Disappears

I really do appreciate the work the Seattle Department of Transportation is doing to implement the 2007 Bicycle Master Plan.  But every once in awhile I come across something that just doesn't quite make sense.  Here's one example:

I'm riding north on Western Avenue in a very nice bike lane separated from traffic by a wide painted buffer.  As I approach the intersection with Battery, where cars are given a right-turn only lane in order to enter Highway 99, the buffer disappears.  Instead I see these confusing markings:

Two bike sharrow symbols now alternate with two right-turn only symbols.  What am I supposed to do, on a bike or in a car, when I approach this intersection?  These symbols tell me only that somehow, bikes and cars are supposed to get along and not run into each other.

Here's another example.  

This is the bike lane heading south on Alaskan Way. To the right are Port of Seattle facilities; most of the traffic along this stretch consists of semi trailers picking up containers at the port.  Again, there's a nice section of separated bike lane with a wide, painted buffer.  But without warning, the buffer disappears.  Can you see how close the wheels of those semis are to the painted line of the bike lane?  I choose to ride on the sidewalk here.

The big problem with these separated bike lanes that don't go the distance: the whole idea is to keep people on bikes separated from cars and trucks.  There are some people riding bikes who don't mind riding six inches from a semi trailer, or negotiating the weave with traffic at right turns.  Those separated lanes are for those of us who don't want to be tangling with traffic like that.  If the lane that keeps me safe suddenly ends, what am I supposed to do?  Turn around and go home?  I look forward to the day when I can choose a route that separates me from traffic, and know when I start that I can follow this route in comfort to my destination.

I'm sure the drivers of those big trucks would also prefer a route that consistently gives them a good separation from people on bikes.  Bike infrastructure makes travel better for everyone, not just those of us on the bikes.