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Contrarian rebelliousness, the birthright of cyclists

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Contrarian rebelliousness, the birthright of cyclists

Old 01-05-24, 03:54 PM
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Originally Posted by PeteHski
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.
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.
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Old 01-06-24, 06:10 PM
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Originally Posted by PeteHski
Itís all about calculated risk. The potential consequences of something going wrong at high speed are always worse, but the risk itself may still be relatively low.
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.

Originally Posted by PeteHski
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 Iím not too keen on driving around in old cars that are often lethal death traps in any collision with modern cars or roadside furniture.
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..
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Old 01-06-24, 06:13 PM
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Originally Posted by Alan K
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.
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
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Old 01-06-24, 07:14 PM
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Originally Posted by Jay Turberville
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
High torque at low speed (RPM) associated with electric motors is their inherent nature.
If it wasnít 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.
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Old 01-06-24, 07:15 PM
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Originally Posted by Jay Turberville
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..
I have no illusions about speed and kinetic energy. Iím an ex F1 race engineer. I have also been driving for almost 40 years with zero accidents. Probably done close to a million road miles. That doesnít mean I get complacent either. But Iím not scared of driving fast when the risk of a collision or vehicle failure is extremely low. As it happens, in the UK, the fastest I risk driving on the motorway is about 85 mph and I usually cruise at 77 mph. Points on your license are the biggest risk if you regularly drive faster.
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Old 01-06-24, 07:27 PM
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Originally Posted by Jay Turberville
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..
You seem to be ignoring the huge mass differential between a car and an unprotected person.

E(k) = 1/2 m v^2
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Old 01-07-24, 01:23 PM
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Originally Posted by Alan K
You seem to be ignoring the huge mass differential between a car and an unprotected person.

E(k) = 1/2 m v^2
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.
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Old 01-07-24, 02:00 PM
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Originally Posted by PeteHski
<snip> Points on your license are the biggest risk if you regularly drive faster.
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.
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Old 01-07-24, 03:47 PM
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Originally Posted by Jay Turberville
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.
Not to belabor the point, but you must realize that kinetic energy is directly proportional to the mass whereas it is proportional to velocity raised to the power of 2 (as in an exponential relationship).

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.
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Old 01-07-24, 03:53 PM
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Originally Posted by Jay Turberville
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.
But bad things happen only to others and Iím a fantastically skilled driver!

That used to be the attitude of a friendís 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.
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Old 01-07-24, 03:59 PM
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Originally Posted by Jay Turberville
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.
The most dangerous roads I drive on (by far) are the narrow, winding rural roads with a 60 mph limit. Head on collisions on those roads are often fatal and they happen quite often. You literally have a couple of feet clearance either side on many of those roads. Quite a few of these roads (usually where there has been a history of fatalities) have been reduced to a 50 mph limit in recent years, which is not a bad thing, but still likely to kill you in a head-on. By contrast, motorways are pretty safe, even at well above the 70 mph limit in favourable conditions. But only the Germans appear to accept that. Now I havenít studied the death rate on German Autobahns compared to other countries, but Iím guessing it isnít unusually high.
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Old 01-07-24, 04:07 PM
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Originally Posted by Alan K
But bad things happen only to others and Iím a fantastically skilled driver!

That used to be the attitude of a friendís 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.
When you work in motor racing you come across a lot of guys who tend to have ďbad thingsĒ happen to them on a fairly regular basis and that includes the race drivers themselves - who are not generally renowned for their safe road driving! The only road crash I have personally been involved in (as a passenger) was with a pro race driver behind the wheel.
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Old 01-09-24, 10:58 PM
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Originally Posted by Jay Turberville
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.
When you have all of the facts, well, more of the facts than are being discussed here, you begin to understand that speed alone is not the biggest problem. I knew that. Just by using what I know about drivers and cars and people. Why don't you? Here, listen to this recent podcast done by the New York Times called "The Daily". It's a deep dive on the subject (not deep enough though) so make sure you have more than 20 minutes clear.
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