I’ve spent considerable time on a motorcycle (170,000 miles or so), and the only occasions where people have violated my right-of-way were folks changing lanes without looking over their shoulder.
In England, motorcyclists call the OP’s kind of accident (left turn in front of the bike) a SMIDSY, which stands for “sorry mate, I didn’t see you.” There are a number of factors at work in that situation:
-you (as a bicyclist or motorcyclist) present a small profile when viewed from the front.
-As you approach directly toward that left-turner, your apparent size doesn’t change very much until you’re very close, so it’s hard for them to gauge your distance.
-Because your apparent size doesn’t change very much until the last second, you don’t stand out relative to the background.
-in some circumstances, your coloration may also help you blend in with the scenery behind you; a driver doing a too-quick visual scan may not notice you.
This video explains the issues for motorcyclists, and offers tips on getting noticed and avoiding SMIDSY accidents.
Things that I think help me:
-riding a fat sport-touring bike. I have a BMW R1200RT, similar to this one. It takes up more space in an observer’s field of view; it’s harder to miss in quick visual scan.
-Extra lighting. I have yellow driving lights mounted low on the forks. The unusual color (and location) catches a viewer’s eye.
-I wear a high-viz yellow riding jacket and a white helmet; this will never blend in unless everything behind me is also high-viz yellow and white.
-When approaching intersections where waiting traffic could cross my path, I slalom back and forth within my lane, producing apparent motion in the viewer’s eye, forcing him to take notice.
There are things a bicyclist can do, too. Maybe not full-time 55-watt driving lights, but a flashing white or yellow headlight might help, along with bright colors. Slalom when possible.
I can think of some instances where parallel traffic could hide a bicyclist from left-turners: a car passing you could hide you from the left turner, and as soon as he gets through the intersection, the left turner makes his move just at the moment you are entering the intersection, and SPLAT. If the left-turner notices you before you are hidden by that passer (because you wore bright colors and had a flashing headlight), then you may be saved from a collision. But just in case he doesn’t notice you, all you can do is be ready - cover the brakes so you can stop in time if at all possible, and try to keep an eye on the left-turner. Sometimes you can see through the windows of the passing vehicle, and even if you can’t, sometimes he’ll begin his turn before he disappears from your field of view - and if you can see that, you have time to hit the brakes and scrub off some speed (possibly stop) before a collision happens.
In the case of the Amazon excec, details are sketchy. All I read was that she was going downhill on Skyline Boulevard when she was struck. Skyline Blvd is a pretty twisty road, and “going downhill” on a bicycle usually involves hauling ass: nobody who had had to pedal themselves uphill wants to hit the brakes during a downhill run unless absolutely necessary. It’s entirely possible that in this particular case she contributed to the accident by going too fast for conditions (speeding, or even going just under the speed limit around blind corners).