Great idea. Maybe best to start with a set of crash types and keep it to on-road involving motor vehicles
I had a look for some standard crash classifications and found
http://crashstat1.roads.vic.gov.au/cras ... ndices.pdf
But it looks too complicated for this exercise so here is my starter for ten in alphabetical order - for refinement before polling:
1 Close shave/hit from behind/sideswipe (both going in same direction)
2 Dooring
3 Left hook (Car turning left on top of bike)
4 Merging at pinch points (islands, parked cars, roundabout entrance)
5 Right hook (Oncoming car turns right into bike)
6 Road condition (loose surface, potholes, tram tracks)
7 T-boned at intersection/roundabout
8 T-boned by car pulling out of driveway or car park
Maybe a multi-choice poll. Need to decide if you want to separate out "chance of happening" from "severity when it does" or just combine the two into "what do you worry about most" which is probably easiest to start with. Would also to be good to get a reason why it is a worry. For instance I'd vote 1, 4, 7 because:
1: I've got no control over the actions of the car and it happens a lot. Coming from behind makes it harder to manage.
4: Similar to 1 but I've got a bit more control over the situation if I'm vigilant
7: Happens a lot and even when you think the car has given way they can take off. But at least you can see what's in front.