Crash investigations tend to have conclusions like "A happened, and that would have been survivable except that B also happened, and the pilots were distracted dealing with A while B was the more serious problem." There's a whole field of "cockpit resource management" which deals with such issues.
The NTSB's job is not to assign blame. It's to understand exactly what happened and figure out how to keep it from happening again.
This crash is somewhat similar to the four other Tesla crashes where a stationary obstacle was partially obstructing the left edge of a lane. We know that Teslas will plow into such obstructions. Here's the area of 101 leading up to the crash.[1] Note the width of the space between the lines marking the gore area, the pointy section as the exit lane tapers off. It becomes a full lane wide, and widens very slowly. It's possible that the lane following system locked into the gore area as a lane, and followed it right into the barrier.
CALTRANS standards call for a sign in the gore area.[2] But drivers keep hitting them. Replacing them is dangerous work, because there's live traffic and not enough room for a block vehicle. Especially here, because this is a left exit designed for high speed. So one of the options is to put the sign overhead, well ahead of the split. That's what CALTRANS did here. Tesla's system, of course, does not understand such a sign.
Federal standards recommend striping in the gore area.[3] But CALTRANS does not usually do that. Probably because standard truck-mounted lane striping sprayers can't do it without shutting down the freeway.
I look forward to seeing NTSB's take on all this.
[1] https://www.google.com/maps/@37.4107387,-122.0752862,3a,75y,... [2] http://www.dot.ca.gov/trafficops/tcd/exit-gore.html [3] http://www.fdot.gov/roadway/ds/06/idx/17345.pdf
But if it is prioritizing "I'm in a lane, so I'm cool" over "I'm hurtling toward a wall with a very visible marker" then clearly more work needs to be done. (Worse still if it can't recognize such a visible obstruction in the lane.) And, I'd say, should have been done before they were turning people loose with it.
