Taken from the Hurt Report, a study done to examine motorcycle accidents and their causes:
Summary of Findings
Throughout the accident and exposure data there are special observations which relate to accident and injury causation and characteristics of the motorcycle accidents studied. These findings are summarized as follows:
1. Approximately three-fourths of these motorcycle accidents involved collision with another vehicle, which was most often a passenger automobile.
2. Approximately one-fourth of these motorcycle accidents were single vehicle accidents involving the motorcycle colliding with the roadway or some fixed object in the environment.
3. Vehicle failure accounted for less than 3% of these motorcycle accidents, and most of those were single vehicle accidents where control was lost due to a puncture flat.
4. In single vehicle accidents, motorcycle rider error was present as the accident precipitating factor in about two-thirds of the cases, with the typical error being a slideout and fall due to overbraking or running wide on a curve due to excess speed or under-cornering.
5. Roadway defects (pavement ridges, potholes, etc.) were the accident cause in 2% of the accidents; animal involvement was 1% of the accidents.
6. In multiple vehicle accidents, the driver of the other vehicle violated the motorcycle right-of-way and caused the accident in two-thirds of those accidents.
7. The failure of motorists to detect and recognize motorcycles in traffic is the predominating cause of motorcycle accidents. The driver of the other vehicle involved in collision with the motorcycle did not see the motorcycle before the collision, or did not see the motorcycle until too late to avoid the collision.
8. Deliberate hostile action by a motorist against a motorcycle rider is a rare accident cause. The most frequent accident configuration is the motorcycle proceeding straight then the automobile makes a left turn in front of the oncoming motorcycle.
10. Intersections are the most likely place for the motorcycle accident, with the other vehicle violating the motorcycle right-of-way, and often violating traffic controls.
11. Weather is not a factor in 98% of motorcycle accidents.
12. Most motorcycle accidents involve a short trip associated with shopping, errands, friends, entertainment or recreation, and the accident is likely to happen in a very short time close to the trip origin.
13. The view of the motorcycle or the other vehicle involved in the accident is limited by glare or obstructed by other vehicles in almost half of the multiple vehicle accidents.
14. Conspicuity of the motorcycle is a critical factor in the multiple vehicle accidents, and accident involvement is significantly reduced by the use of motorcycle headlamps (on in daylight) and the wearing of high visibility yellow, orange or bright red jackets.
There are plenty more findings, I just posted the top 14. Keep in mind this study was done in the 70s, so some of the information is not applicable anymore because bikes have changes so much since then, mostly in reference to motorcycle engine sizes. Here are some more interesting tidbits:
27. Almost half of the fatal accidents show alcohol involvement.
28. Motorcycle riders in these (alcohol related) accidents showed significant collision avoidance problems. Most riders would overbrake and skid the rear wheel, and underbrake the front wheel greatly reducing collision avoidance deceleration. The ability to countersteer and swerve was essentially absent.
42. Injury severity increases with speed, alcohol involvement and motorcycle size.
Here is some information from a study done over in Europe, where they have more bikes on the road in relation to total vehicles. The results are very similar.
Interestingly, there was
another report done in early 90s for the insurance companies, and they report that motorcyclists who drank and ran off the road accounted for 41% of the total fatalities, more than twice that of any other cause, including the dreaded left turner. Keep in mind that statistic refers to fatalities, not just motorcycle accidents.