Old post but circumstances don't change
Years ago I worked in the City next to San Jose as an LEO. My thoughts go out to a brother Officer and his wife, what a shame. Even though this happened 4 years ago, the circumstances are timeless.
The response by the responsible driver is fairly typical and in most cases its true. Not an excuse, but subconsciously or not drivers of cars aren't tuned in to be on the look out for motorcyclists. That is why we are constantly told to ride like you are invisible, because in reality to many drivers we are. It was said the driver didn't see the the Officer because cars making a right turn onto the road he was coming out of blocked his view. You can deduce if that is true then in theory the same cars would have blocked the view of him from the motorcyclist point of view. To me that doesn't relieve the driver one bit for not only violating the right of way of the motorcyclist from a stop sign, but also I don't see any mitigating circumstances either (unless there is an road engineering flaw) when this event gets its day in Civil Court. We have as much right to be on the roadway as a car. For example, if you are rear ended and killed I don't buy the argument that if you had been in a car you could have survived, therefore the responsible driver should treated with less scrutiny.
Every driver has a responsibility to be aware of unforeseen possibilities, in this case the motorcyclist legally in his lane. This reminds me of a common right of way accident scenario whereby a car traveling down the two way left turn lane in preparation of making a left turn gets hit by a car coming out of a driveway, coming from right to left. This to me relates to the term "rolling blind spot". It occurs with frequency in heavy traffic shy of an intersection when traffic stacks up and one then two then three drivers stop (in the case of a three lane split roadway) in their respective lanes to yield to the outgoing driver. A courtesy service well taken, but an invitation to be extra cautious. Actually the stopped driver in the number one lane has to be aware of the fact if he signals the driver to continue across his lane with a hand gesture he could be partially held responsible in Civil Court in the event of an accident. So if your going to provide hand signals, be aware of this and be careful. We all know to be aware of these situations developing in front of us and I never proceed pass the "gap" in traffic as described above because you have identified a potential accident in the making. You know Murphy's Law applies and there will be a car cutting in front of you, even if you can't see it yet.
I hate to Monday morning quarterback but based on what I've heard so far that same set of circumstances at the accident scene in Sonora has been duplicated many times. You should recognize based on your peripheral vision the potential danger forming ahead and prepare for the worst. The driver of the car pulling away from the stop sign has the legal responsibility to yield the right of way, but ultimately you are the only one that can save your own ass. Some would say there is nothing you can do if a driver pulls out directly in front of you for no reason, "out of the blue". I argue again in the same way professional motorcycle instructors and racers always talk about looking up the road. That includes roadway appraisal and peripheral objects. Once you see that car or truck getting ready to pull out in front of you there are mannerisms the driver makes that could be interpreted as warnings. Much in the same way we used the term "furtive" when it came to someone just about ready to commit a crime, i.e., "furtive eye movements".
Again, its a sad situation all the way around, obviously, this had to be extra tragic if they had kids.