First of all, they don't compare - cycling is a different animal from motorcycle riding. The motorcycle, because it has a motor, has the ability to accelerate out of situations much faster than a bicycle. When cycling, much of whether you crash is contingent on how developed a rider you are, and how well you pay attention to your surroundings. Because of the slower speeds in cycling, it would seem more accidents occur as the fault of the cyclist not watching for cars that might pull out in front of him/her and car doors opening as they pass.
Ascending hills is its own science as by hearing alone, a cyclist, while also concentrating on their ride, has to gauge by sound how quickly and closely an approaching vehile is coming to them .
Descending hills is much of the same as riding on the flats; except increase the speed two or three fold, and one has to be aware of cars, road conditions, and crosswinds as they descend.
Given a motorcyclist doesn't need to worry about approaching cars while climbing and crosswinds and road divots while descending, a motorcycle definitely has those advantages sewn up.
