Even so, a bike is capable of moving at speeds high enough to cause severe harm to the rider or pedestrians. What if the threshold for a test was based on the average speeds of the vehicle?
Have there been a lot of pedestrian deaths (or serious injuries) caused by cyclists in your area? How does it compare to deaths/accidents caused by collisions with cars?
I'm also pretty sure that most of those accidents could be avoided by having better cycling infrastructures.
There have been a couple. However, when it does happen it gets a lot of media attention, the most recent incident taking place on Oxford Street, a popular shopping street in London: http://www.bbc.co.uk/news/uk-england-london-41263926
I'd say the licensing regimes should be set at a level that's proportionate to the number of deaths of others caused by that kind of vehicle, i.e. consider the number of other road users killed per year by every 10000 cars/bikes/bus-passengers/pedestrians/.... (perhaps as a QALY calculation to take into account serious injuries as well). Modes where that number is higher should have their licensing requirements made stricter, modes where that number is lower should have their licensing requirements relaxed.
If we'd be playing billiards you'd be right. But in traffic the objects are driven by humans. And then speed becomes a factor.
Speed and impulse. Speed is a factor in the risk of collision (since our brain has limited real-time processing chops), and then when a collision happens, impulse is indeed an important consideration, together with another factor: protection level.
In a world with just those three factors, eg no traffic rules or speed limits, a car makes lots of accidents (because it's fast) and when they happen, a lot of energy and thus destruction are involved (because they're heavy), and also, while the car driver is protected by his/her big heavy steel box, the collision counterpart - a cyclist - might not be.
This asymmetry trinity is exactly why we should have (and have, to some extent) road rules and license regulations to level the playing field so that the outcome of the equation moves a bit in favour of the slow, light, and less well collision-insulated.
So if one endeavours to go inside a heavy (dangerous to others) steel box (that nicely protects you) that goes fast (you will have less time to react, and moreover, you "steal" other drivers attention because they constantly have to be on the lookout for "is there something fast coming? is there something fast coming?") - then yes, the onus is on this car driver to be responsible and submit to road rules, licensing, and heavy fines.
Then there's other non-collision factors that make current man-driven combustion engine cars look very silly indeed: they are noisy, pollute, take up a lot of space even when not moving (which is most of the time) and require expensive infrastructure. That leads us to ask ourselves - who on earth designed this system? And in the question belies the answer: no one did - there were coaches, we put a petrol engine in it, and went from there without any vision.
With today's technology and insight, given a blank slate (there are no roads, no cities, no nothing - just a can full of people that need to work and live and travel, to be poured out on the green fields where we will build our infra) , NO ONE would design a transportation system this silly.
