One of the main reasons motrocyclists crash is not due to cars hitting the rider, but its usually when somebody comes up to a curve to fast and get scared and hit the brakes wich throws them way off balance and cause the bike to spin out from underneath them. When hitting a curve too fast remember that you can always turn and lean more to compensate, hitting the brakes when going to fast is more dangerous than turning harder to make up.
as few as possible
There are lots of motorcycle incidents a year around 60 million die a year!
Combination of factors
In what country, in what time period are the two obvious elements you left out of your question.
According to the NHTSA, survival rates are not very good for motorcycle crashes. According to a chart, out of 100,000 registered motorcycles, the 2004 fatality rate was 69.33.
Yes, until the motorcycle crashes or stops and as fast as is necessary.
Usually inexperienced riders and wreck less drivers who claim they did not see the motorcycle.
49%
what leads up to most crashes
No, it is not. All serious motorcycle drivers use a helmet, especially if they are driving on highways or in other places where there is a lot of traffic. Head injuries from motorcycle crashes are frequently fatal so use a helmet at all times regardless of whether the law requires it or not.
speed
i think it is at an intersection. i have it on my traffic school online thing. hope it helped.. =]