Contrarian rebelliousness, the birthright of cyclists
#101
Senior Member
I remember way back at school 40 years ago reading a book about the predicted future of automobiles that was introducing the idea of electric motors eventually replacing the ICE. Meanwhile, the milkman was crawling around at 10 mph in a noisy electric milk float. At that point EVs were not looking very appealing! But times change and the technology moves forward.
Possibilities using motors have been known for a long time, it was energy to drive them that needed to be improved… and still further improved.
#102
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For example I would quite happily take the risk of driving at 100+ mph on a clear stretch of motorway in a modern high performance car. The only thing that stops me is the potential court visit and driving ban. On the other hand I’m not too keen on driving around in old cars that are often lethal death traps in any collision with modern cars or roadside furniture.
And I guess that's my main point. I don't think most people understand how much adding speed multiplies the risk of death and injury and likelihood of having an accident. Dropping to 30 mph from 45 mph halves the energy once again. And this is why pedestrian deaths are so much less likely at 30 mph and almost nonexistent at 20 mph (another halving of kinetic energy). The kinetic energy of the car is low enough at those speeds to give the unprotected pedestrian a good chance of survival..
#103
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Didn’t Porsche design electric car way earlier in the 1920s. The only reason it didn’t catch on then when 20-30 MPH was considered good, is the weight of Pb-acid batteries.
Possibilities using motors have been known for a long time, it was energy to drive them that needed to be improved… and still further improved.
Possibilities using motors have been known for a long time, it was energy to drive them that needed to be improved… and still further improved.
https://en.wikipedia.org/wiki/Histor...ectric_vehicle
#104
Senior Member
If Wikipedia is to be believed, electric cars had the early lead in speed up until around 1910 or so.
https://en.wikipedia.org/wiki/Histor...ectric_vehicle
https://en.wikipedia.org/wiki/Histor...ectric_vehicle
If it wasn’t for limitations of lead-acid batteries, electric cars may have had a different kind of market. Of course, the industry associated with cheap gas of the day, would have pushed very hard to remain on the top.
And even now this battle is far from settled.
#105
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Or the failure to actually calculate risk. In most situations, faster is riskier. And it tends to increase risk geometrically, not linearly. Reaction time, braking distance and even effective field of view are all worse. Yes, there are exceptions where faster is better - such as traveling at the same or very similar speed as accompanying traffic. For sure, slower is riskier in that situation.
Maybe looking at the statistics on the likelihood of death at different vehicle collision speeds you would have you reconsider. The kinetic energy of your body at 100 mph (I'm not counting any "plus") is 2.36 times that if it is travelling at 65 mph. And going 65 mph has about twice the kinetic energy of going 45 mph. If you actually collide with something solid head on at 45 mph, your risk of survival is about 50/50. So its important to get the car down to below that speed . At 100 mph, you need to scrub off about 75% of your kinetic energy to have a decent chance of survival.
And I guess that's my main point. I don't think most people understand how much adding speed multiplies the risk of death and injury and likelihood of having an accident. Dropping to 30 mph from 45 mph halves the energy once again. And this is why pedestrian deaths are so much less likely at 30 mph and almost nonexistent at 20 mph (another halving of kinetic energy). The kinetic energy of the car is low enough at those speeds to give the unprotected pedestrian a good chance of survival..
Maybe looking at the statistics on the likelihood of death at different vehicle collision speeds you would have you reconsider. The kinetic energy of your body at 100 mph (I'm not counting any "plus") is 2.36 times that if it is travelling at 65 mph. And going 65 mph has about twice the kinetic energy of going 45 mph. If you actually collide with something solid head on at 45 mph, your risk of survival is about 50/50. So its important to get the car down to below that speed . At 100 mph, you need to scrub off about 75% of your kinetic energy to have a decent chance of survival.
And I guess that's my main point. I don't think most people understand how much adding speed multiplies the risk of death and injury and likelihood of having an accident. Dropping to 30 mph from 45 mph halves the energy once again. And this is why pedestrian deaths are so much less likely at 30 mph and almost nonexistent at 20 mph (another halving of kinetic energy). The kinetic energy of the car is low enough at those speeds to give the unprotected pedestrian a good chance of survival..
#106
Senior Member
Or the failure to actually calculate risk. In most situations, faster is riskier. And it tends to increase risk geometrically, not linearly. Reaction time, braking distance and even effective field of view are all worse. Yes, there are exceptions where faster is better - such as traveling at the same or very similar speed as accompanying traffic. For sure, slower is riskier in that situation.
Maybe looking at the statistics on the likelihood of death at different vehicle collision speeds you would have you reconsider. The kinetic energy of your body at 100 mph (I'm not counting any "plus") is 2.36 times that if it is travelling at 65 mph. And going 65 mph has about twice the kinetic energy of going 45 mph. If you actually collide with something solid head on at 45 mph, your risk of survival is about 50/50. So its important to get the car down to below that speed . At 100 mph, you need to scrub off about 75% of your kinetic energy to have a decent chance of survival.
And I guess that's my main point. I don't think most people understand how much adding speed multiplies the risk of death and injury and likelihood of having an accident. Dropping to 30 mph from 45 mph halves the energy once again. And this is why pedestrian deaths are so much less likely at 30 mph and almost nonexistent at 20 mph (another halving of kinetic energy). The kinetic energy of the car is low enough at those speeds to give the unprotected pedestrian a good chance of survival..
Maybe looking at the statistics on the likelihood of death at different vehicle collision speeds you would have you reconsider. The kinetic energy of your body at 100 mph (I'm not counting any "plus") is 2.36 times that if it is travelling at 65 mph. And going 65 mph has about twice the kinetic energy of going 45 mph. If you actually collide with something solid head on at 45 mph, your risk of survival is about 50/50. So its important to get the car down to below that speed . At 100 mph, you need to scrub off about 75% of your kinetic energy to have a decent chance of survival.
And I guess that's my main point. I don't think most people understand how much adding speed multiplies the risk of death and injury and likelihood of having an accident. Dropping to 30 mph from 45 mph halves the energy once again. And this is why pedestrian deaths are so much less likely at 30 mph and almost nonexistent at 20 mph (another halving of kinetic energy). The kinetic energy of the car is low enough at those speeds to give the unprotected pedestrian a good chance of survival..
E(k) = 1/2 m v^2
#107
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At 23 mph, the fatality rate is about 10%. It goes to 25% at 32 mph and 50% at 42 mph. By 50 mph the rate is 75% and it hits 90% at 58 mph.
#108
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Even if you were a driver of only average ability, you odds of dying in a car crash is only about 1 in 200 (assuming 40 years driving at 25,000 miles/year). Even if habitual speeding doubled your odds of a crash, your odds of getting a citation would certainly be greater from habitual speeding. But the likelihood of something happening isn't the only thing to consider when evaluating risk. Severity of outcome should factor in as well.
#109
Senior Member
No. I'm using statistics on pedestrian deaths and inferring that the rapid rise is due to the rapid increase in the car's kinetic energy as speed increases - since the two seem pretty well correlated. The effect of the mass difference increases roughly geometrically with increased speed.
At 23 mph, the fatality rate is about 10%. It goes to 25% at 32 mph and 50% at 42 mph. By 50 mph the rate is 75% and it hits 90% at 58 mph.
At 23 mph, the fatality rate is about 10%. It goes to 25% at 32 mph and 50% at 42 mph. By 50 mph the rate is 75% and it hits 90% at 58 mph.
In practical terms, when a pedestrian gets hit by an automobile, he/she/them/xe has two impacts - 1) when the automobile meets the near stationary body and 2) when the propelled body through the transferred force meets the stationary pavement. End result is not in favor of a pedestrian and I will highly recommend them to stay out of the way of cars even when they are going <10 MPH, irrespective of who has the right of way.
#110
Senior Member
Even if you were a driver of only average ability, you odds of dying in a car crash is only about 1 in 200 (assuming 40 years driving at 25,000 miles/year). Even if habitual speeding doubled your odds of a crash, your odds of getting a citation would certainly be greater from habitual speeding. But the likelihood of something happening isn't the only thing to consider when evaluating risk. Severity of outcome should factor in as well.
That used to be the attitude of a friend’s son, until he rear-ended someone quite hard because the driver in front him had the audacity to slam on her brakes on a green light because a pedestrian was illegally crossing the sidewalk.
#111
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Even if you were a driver of only average ability, you odds of dying in a car crash is only about 1 in 200 (assuming 40 years driving at 25,000 miles/year). Even if habitual speeding doubled your odds of a crash, your odds of getting a citation would certainly be greater from habitual speeding. But the likelihood of something happening isn't the only thing to consider when evaluating risk. Severity of outcome should factor in as well.
#112
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But bad things happen only to others and I’m a fantastically skilled driver!
That used to be the attitude of a friend’s son, until he rear-ended someone quite hard because the driver in front him had the audacity to slam on her brakes on a green light because a pedestrian was illegally crossing the sidewalk.
That used to be the attitude of a friend’s son, until he rear-ended someone quite hard because the driver in front him had the audacity to slam on her brakes on a green light because a pedestrian was illegally crossing the sidewalk.
#113
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No. I'm using statistics on pedestrian deaths and inferring that the rapid rise is due to the rapid increase in the car's kinetic energy as speed increases - since the two seem pretty well correlated. The effect of the mass difference increases roughly geometrically with increased speed.
At 23 mph, the fatality rate is about 10%. It goes to 25% at 32 mph and 50% at 42 mph. By 50 mph the rate is 75% and it hits 90% at 58 mph.
At 23 mph, the fatality rate is about 10%. It goes to 25% at 32 mph and 50% at 42 mph. By 50 mph the rate is 75% and it hits 90% at 58 mph.