Originally Posted by
base2
According to the numbers thrown around in this very thread: 0.012 * 0.03 = 0.00036 per cent of Americans have photosensetive epilepsy.
Of those 0.00036 per 100 Americans with photosensetive epliepsy, how many are on the bike path?
Say, you take the most bussiest spot of the busiest bike path in a major metropolitan area...Lets pick Seattle on January 14, 2019 at 3987 bicycle crossings. Lets assume for simplicity that each crossing represents 1 person. Tandems, triple's, Quads, quints are pretty rare bicycles...Ok. Lets take the 3987 crossings & multiply the 0.00036 rate and see what we get.
1.43532 people with photosensetive epilepsy would have crossed the busiest portion of the busiest bike path on the busiest day. Worst case scenario!
Nobody is saying photosensetive epilleptics don't matter, but geez, where do we draw the line on normal people just going about their lives & realize that just existing poses risks?
Here is some homework: Of that less than 1 1/2 persons that cross, how many experience an on coming strobe? We would need a rate of strobe users among all cyclists on that crossing. To Then multiply that by the frequency that strobes actually induce seizure & thus harm.
Homework hint:
The final quantification of actual risk at the busiest crossing of the busiest path on the busiest day imposed to photosensetive epilleptics would be the formula actual harm = 1.43524 * (strobe rate * strobe seizure rate)
Anyone care to chime in with the rates needed to solve the formula?
If you really want to do the risk analysis here, you are looking at the wrong part of the equation. It is admittedly a slim chance of encountering a photosensitive epileptic, however what's the offsetting benefit of using strobes that would outweigh that minimal risk?
On a path, there is absolutely no safety benefit to using a fast strobe, and it almost certainly makes the close oncoming bike pass more dangerous due to the rather obvious effect of making the rider with the strobe and the bikes around him harder to see at close range. Strobes are good for only one purpose, they make distant objects easier to pick out from the background--at close range, they are a detriment. As a rider, is the bigger threat from a distant cyclist or the one right in front of you?
So basically, on the one side you have a small chance of causing a seizure to someone, which is an external risk you impose on others to actually decrease your own and others' safety.
Great logic, good luck with it. The logic might work better on roads, where the case for the usefulness of strobes might be stronger and the benefit side of the equation may therefore be rationally weighted against the risks to epileptics.
BTW, the bike path math is impossible because, as I laid out before, there is reason to assume that the distribution of epileptics among the population is not random. There may be a disproportionate number of people who are riding bikes or walking on a path because their seizure disorder prevents them from getting drivers licenses. I understand that the proportion is probably still quite small, just not quite as small as you make it out.