Originally Posted by
RazrSkutr
You're having an argument with someone in which you're asserting that 1.9% versus 1.4% are clearly distinguishable in a study with circa 1000 datapoints?
[...]
No. I'll guide you back through so you can see what exactly was asserted.
It was Forester who "asserted" that sideswipe/misjudged pass collisions were "a major source of collisions" and that they occurred "about as frequently" as direct hits from behind. Then, he helpfully provided evidence confirming that neither of these assertions was remotely true.
The 1.9 and 1.4 are immaterial; those are percentages within the subset of urban crashes, in which neither type of same-direction collision is a significant factor. In rural crashes, however, they are much more frequent, and the direct hit is reported roughly
three times as often as the sideswipe/misjudged pass in rural settings in that data set (~14 vs ~5%), as the data posted by Forester shows. In another more recent study of crashes in Washington state by Ralph Wessels, there were like six times as many direct hits from behind as sideswipes/misjudged passes overall iirc. So that is a lot different than 1.4 vs. 1.9.
That is why I can assert that direct hits from behind occur far more frequently than sideswipes. In fact, I think we can even say that these numbers suggest that a cyclist is more likely to get hit from behind while taking the lane on a two-lane highway, by a driver who doesn't notice them at all, than hit by a driver who sees the cyclist but misjudges the pass.
Another thing. Concerning the relative deadliness of the direct hit from behind type wreck. It is by far the most deadly of all the thirty-something different accident types tallied by Cross-Fisher, accounting for roughly 25% of cyclist fatalities (even though it is not a significant source of crashes in urban settings at all.) In sharp contrast, the sideswipe/misjudged pass does not register as a significant source of fatalities.
This is actually quite a bit worse for the direct hit than it looks at first glance. Consider that almost none of those hits-from-behind involve child bicyclists -- it is almost exclusively an adult wreck -- yet child bicyclists accounted for a quite high percentage of total cyclist fatalities when that study was made. At least 20%. So the portion of fatalities involving adult cyclists that are caused by a direct hit-from-behind is actually more like 1-in-3. The percentage of rural-setting fatalities caused by a hit-from-behind must be very, very high.
The only question that remains for me is -- in what new creative ways will this unwelcome information be aggressively ignored by the VCism crowd?