I wasn’t able to view the video at your blog. Could you post the YouTube link here?

You bring up an excellent point about speed. From what I’ve read in various net motorcycle forums over the years, many riders don’t understand how a motorcycle’s speed can contribute to a left-turning-cage crash. I’ve followed discussions of several crashes recently in which a speeding motorcyclist was killed in a collision with a turning car. Here are some examples:

• Napa, CA, 6/04: After launching hard from a stop light, a 17-year-old sportbike rider traveling 65 mph in a 30 zone hits the driver’s side of a car making an illegal U-turn from the curb. The driver was clearly at fault, but the rider could have prevented the crash by riding with the flow of traffic.
  
  
• Linden PA, 6/06: A rider who may have been racing another motorcycle at 100+ hits a left-turning minivan so hard that the motorcycle penetrates the side door of the van and overturns it. The bike’s fuel tank bursts and starts a fire that kills four occupants in the van.
  
  
• Long Beach, CA, 10/06: This happened just this week. A motorcycle traveling at an estimated 80 mph hits a left-turning car near Long Beach City College, pushing it sideways 15 feet. The motorcycle's fuel tank starts a fire that critically injures the car’s passenger.

In all of the discussions, some participants fixed blame solely on the driver. There seems to be a widespread perception that the left-turning vehicle is at fault regardless of the motorcycle’s speed. For that matter, I don’t fully understand the law myself. I know that in some states, a driver loses right-of-way at a particular increment over the limit by statute. In OH, I think, it’s 20 mph over. I’ve heard the same from a LEO in CA, but that must be case law because I can’t find it in the Vehicle Code. Can you clarify that?

A more important aspect for riders to understand is how speed can make a motorcycle difficult to avoid even when the driver is reasonably attentive. At high speed a motorcycle becomes a danger that a driver must reckon with when it is still far down the road. In the worst case, the motorcycle is on a collision course even though it is out of sight, beyond an intervening bend or rise. The driver checks carefully, sees clear roadway, and begins his turn. But before he completes it, a motorcycle rounds the bend and collides with the car. Driver inattention has nothing to do with that kind of crash.

A speeding rider can also be in danger when the road is straight, level, and unobstructed because a driver has a limited decision horizon or span of road he checks before proceeding. He looks only as far as he must to make sure his maneuver won’t interfere with traffic moving at the speed he expects to find on that road. It’s an intuitive judgment, not a precisely measured one, but if a driver can safely cross 200 feet ahead of the normal 30-mph traffic, he won’t worry about vehicles 400 feet away because he assumes they’re moving at normal speed.

Even if a driver does see a motorcycle coming from beyond his decision horizon, he may not judge its speed correctly. When an object is moving straight toward an observer, the visual cue for speed is increasing size. Since a distant motorcycle is just a small point in the visual field to begin with, it doesn’t grow noticeably in size until it is quite close. A fast-moving but far-away motorcycle is an inconsequential dot in the background.

A motorcycle’s acceleration can be deceptive too. From a standing start, an aggressively accelerated motorcycle can cover ground in half the time it takes a car. A driver waiting to turn left might ignore vehicles stopped at a light a half-block ahead because they’re too far away to be a threat. He expects a safe 10-second interval in which to turn, but he’ll have only 5 seconds if one of them is a hard-charging motorcycle.

Finally, speed reduces a motorcycle’s visibility to drivers because it decreases the time spent in a limited visual field, and that reduces the chance of being seen. Things happen quickly in traffic. For example, a driver checks his mirrors only briefly before changing lanes—carefully enough to spot a vehicle traveling 5 or 10 mph faster than he, but perhaps not enough to see a speeding motorcycle. If the motorcycle is overtaking with a speed difference of 20 mph, it will be in the visual field covered by the driver’s mirrors only one-fourth as long as it would if the difference were 5 mph. One-fourth the time means one-fourth the likelihood of being seen.

Speed is part of motorcycling. It's built into our machines, and it permeates the culture. But there's good speed and bad speed, and learning the difference is one of those judgment deals that is so difficult to teach. Moreover, no official motorcycle curriculum can condone speeding of any kind, so the lessons end up seeming hypocritical. Somehow it must be communicated to new riders that, while speeding on a string-straight road in the middle of nowhere is merely illegal, speeding in traffic isn't just illegal but can also be deadly.