Motorcycles crash causes

Like all questionnaires that purport to reflect stable characteristics, it is important to determine just how stable or how consistent is a person s score over time. Ozkan et aL (2006) administered the DBQ to 622 drivers and found that over a three-year period the test-retest reliability of the scale scores was only 0.61. This is a fairly low level of reliability and it means that the DBQ can vary significantly over time, as one would expect given the findings that violations tend to diminish with age while lapses tend to increase with age. With a shorter -three-month - test-retest interval the reliability appears to be slightly higher (Parker et aL, 1995), and with a one week interval the test-retest reliability was higher still (Li et al., 2004 obtained r>.80 in China ). The utility of the DBQ, and its close relationship to scales of driver violence and vengeance (Li et aL, 2004) has also prompted the recent development of a Motorcycle Rider Behavior Questionnaire (Elliott et aL, 2007), in order to better understand the causes of motorcycle crashes (see Chapter 16). 

The results are strikingly - and surprisingly - similar, with the principal cause of the crashes in both data sets being the behavior of the driver of the other vehicle, followed by the behavior of the PTW rider. Similar findings were obtained in a British motorcycle causation study where in accidents involving a collision with another vehicle, the motorcycle rider was culpable in less... 

Speed is generally associated with injury severity, but it also has a consistent effect on the likelihood of a crash. The MAIDS crash investigation teams concluded that in 8 percent of the crashes the motorcycle s speed contributed to the crash, compared to only 5 percent of the crashes in which the other vehicle s speed contributed to the crash. In Spain, Lardelli-Claret et al. (2005) assessed the accident causes of all the PTW injury collisions that occurred in Spain from 1993 to 2002, that did not involve a pedestrian, and in which only one of the drivers or riders was considered culpable. With a total data base of 128,273 crash-involved mopeds and 62,005 crash-involved motorcycles, they calculated the crash risk of the culpable riders relative to that of the non-culpable riders. After adjusting for various confounding variables, they found that the factors that were most over-involved in culpable crashes were inappropriate speed (with an odds ratio of 13 for motorcycles and 10 for mopeds), and excessive speed (with an odds ratio of 7 for motorcycles and 6 for mopeds). The effects of speed in general are discussed in much more details in Chapter 8). 

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