Until about a year ago, as far as I know, only two people in about four years had been killed by cyclists. The cases were truly appalling cases of atrocious riding. Whatever the number, two, three, whatever - it is too many and almost for sure, due to truly dreadful, irresponsible riding.
Interesting.
I am well aware of the way energy increases at the square of the speed of a moving body, so it is technically correct that faster means more damage in a collision though on the question of how 'massive' that difference is between 15 and 20 miles an hour, I think you are being hyperbolic. At 15 miles an hour the KE in joules of an 80 kilo bike and man is 0.000694 Joules. Five miles an hour faster it is 0.00123 Joules, under twice the lower speed amount. Massive? I don't know.
However, you ignore my main point which is that the risk of collision is MUCH more a matter of manner of riding than it is of a mere 5 miles an hour of increased velocity.
I ride about 5000 to 6000 miles a year on motorcycles ranging in power between 20hp (15kw power output and 140 kilos dry weight) and 47hp (35kw and 210 kilos dry weight) and I have been riding continually those kinds of distances and power levels for over fifty years. I have not had an accident on my by comparison VERY powerful and weighty machines since about 1970 when I fell off an ancient bsa on a roundabout covered in diesel oil. In all of my driving (add on about 8000 miles a year these days of car driving and in the past that figure was about 15000 miles for about forty years) I have never harmed another person.
Why is this? Well, aside from good luck, I consistently drive and ride with caution and consideration. THIS IS THE KEY FACTOR in safety, though some here are VERY hung up on technical regulations and laws - regulations and laws which any sane person can see are made by half witted PPE graduates, pensioned off lawyers and greasy pole climbers in an utterly dysfunctional parliament and civil service. Yes Stuart, I despise our law making body and its members. What have they got right? Point to ANY feature of government that works or is performing well. I say this as a man of 73 years old who last had a driving penalty in 1971, rightly imposed for exceeding a 30 miles an hour speed limit by a small margin, so I am no wholesale law breaker and criminal. Nonetheless, I laugh at the idea that a throttle which will propel a pedelec at 16 miles an hour is a menace to society and that we must all kowtow to the stupid rule that we must not have one, on pain of court penalties and confiscation. It's a joke. 1.3% of pedestrians injured in ten years between 2005 and 2010 were injured by anyone on a bicycle while 98.7% were injured by a motor vehicle. The numbers of pedestrians (regrettably) killed, amount to about 2 to 3 a year over a long period. These are usually caused by grotesquely bad riding and are exceptional rather than the norm. The courts take a very serious approach to these in contrast to the usually weak penalties imposed on drivers who are generally charged with careless driving rather than dangerous driving.
The menace to society is that man or boy (and it is almost always men and boys) who rides like an a-hole on pavements or with grotesque stupidity on the roads. Pedants and nitpicking sheep may disagree. That is their prerogative. The English disease is to legislate against the freedom of all to curtail the insane behaviour of a few morons. I detest it. Meanwhile, an average of two cyclists are killed each week and 67 are seriously injured by motor vehicles.
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