KiwiNZ:KevinL: Actually, I'm fairly certain the evidence base suggests they're fairly safe in themselves. It's the other vehicles sharing the road that are dangerous.
High speed motorcycle crash is generally more survivable than a high-speed car crash. Probably something to do with momentum and rate of loss of energy (cars don't bounce, they stop).
What evidence do you have to support this, in modern cars there cumple zones, energy transfer in an impact, pyro seat belt pre-tensioners, Airbags, headrests, anti-submarining seats and belts, collapsing staring columns etc etc, on a bike you have a helmet (if worn) leather clothing (if worn), I am not seeing the odds of survival here.
Completely anecdotal (having worked in a tertiary trauma centre for the last 9 years or so) although I'm sure it depends entirely on the situation. I could probably drag something out of the medical literature though - it's hard to generalise as the statistics don't accurately capture the pre-hospital deaths.
However, in a high-energy impact (e.g. head-on collision at >100kph) even with the modern safety features, going from >100kph to zero kph in a matter of seconds involves a massive transfer of energy.
Motorcyclists tend to bounce (and don't stop immediately) and hence lose energy at a much slower rate - consequently the injuries seen are different (generally more long bone injuries rather than deceleration injuries e.g. liver/splenic contusions) but often more survivable.
Edit: One random study plucked out of the ether, done in Greece 2005:
": Of 730 consecutive patients, 444 were motorcyclists (60.8%), 209 were car occupants (28.7%), and 77 were pedestrians (10.5%). Young men constituted the majority of injured motorcyclists whereas older patients (p = 0.0001) and women (p = 0.0001) represented a substantial proportion of the injured pedestrians. With regard to the spectrum of injuries in the groups, craniocerebral injuries were significantly more frequent in motorcyclists and pedestrians (p = 0.0001); abdominal (p = 0.009) and spinal cord trauma (p = 0.007) in car occupants; and pelvic injuries (p = 0.0001) in pedestrians. Although the car occupants had the highest Injury Severity Score (ISS) (p = 0.04), the pedestrians had the poorest outcome with substantially higher mortality (p = 0.007) than the other two groups."