slothropfuck cars and live a little
jordanlundLocal news:
koin.com/…/notorious-intersection-portland-driver…
“The officer spotted a grey BMW going 87 MPH in a 40 MPH zone”
For our European friends:
87 MPH = 140 KPH
40 MPH = 64.4 KPH
otpKinetic energy = mass*velocity^2 in action. Faster you go the harder you stop.
This needs to be updated.
Getting hit by a pickup truck at 30 MPH is similar to getting hit by a Honda Civic at 120 MPH for kinetic energy.
That’s besides the fact that pickups have a much taller hood vs sedans so there are significantly higher rates of head injury.
Taller cars and trucks are more dangerous for pedestrians, according to crash data
I am not sure why the difference in energy related to vehicle mass is relevant here as humans have an insignificant amount of mass compared to either vehicle, so transferred energy should be roughly the same.
However, the difference in how the collision plays out (pulled under Vs thrown above) should be a huge impact
The higher mass and force transmitted by a truck means the human will be thrown further and possible impact other objects at a higher speed
Not all of that energy is transferred. The car doesn’t stop as if it hit a wall. Usually it barely slows down. The human on the other hand gains at most the kinetic energy corresponding to their body mass and the speed of a human bouncing forward off the car at around the same speed as the car was going, so a tiny fraction.
The issue is energy transfer doesn’t care about weight of the human, more kinetic energy will impart more speed to the human during the impact impulse. Imagine a solid bowling ball hitting a beach ball vs a plastic hollow bowling ball hitting a beach ball
The bowling ball will not slow down in the slightest when is hits the beach ball, accelerating the beach ball up to it’s speed.
The plastics ball will lose significant speed hitting the beach ball, bringing itself down so amount of speed and the beach ball up.
I’m going to pick some easy math speeds/masses for demonstration. 2,000 kg sedan, 4,000 kg pickup and 100 kg human. Starting speed of 20m/s and 0m/s. An impact time of 1s.
The sedan hits a pedestrian with (f=ma) of 40kN. It takes 2kN to bring the human up to 20 m/s. So the sedan will be somewhere around 38kN, or 19m/s at the end of it and the human absorbing 1.8-2kN.
The truck has f=80kN. Same 2kN for the human. So the truck will be somewhere around 78kN or 19.5m/s at the end. With the human absorbing 1.9-2kN
In either case the we talking a difference of 1.8-2kN for the human. Regardless the mass (and total force) of the vehicle, the relatively small human as a maximum force they can absorb. And that maximum force is heavily related to the speed of the larger object.
Not to say trucks/SUVs aren’t deadly for other reasons (like where and how the force os transferred)
You are thinking of perfectly elastic collisions. That’s a fantasy and not applicable to the real world. A human body isn’t a beach ball and cars have crumple zones (although I believe pickups suck in this regard as well).
Car crumple zones are tuned to prevent damage to the car, not to pedestrians. If they were they would have airbags on the front of the car. A car can kill a pedestrian by hitting them with a crumple zone, without that zone crumpling.
This means most of the non-elasticity is in the pedestrian’s body; how they flop onto the hood of a normal car, and how their bones crumple and flesh splatters before their brain and vital organs do.
Of course if a car hits a pedestrian hard enough, the crumple zone will crumple to reduce damage to the car, but that’s overkill as far as the pedestrian’s life is concerned.
That said, if you (unrealistically) assume the speed at impact and the geometry of the hood are the same, the difference between a car that weighs 20 times what a person does and one that weighs 40 times that is (40/41 - 20/21), or only about 2.5%.
Realistically, the weight increases the braking distance and the hood geometry makes the pedestrian’s body perish more elastically.
should be a huge impact
I see what you did there.
So my curved front sports car is totally safe to ram into pedestrians with?
/S
I’d rather be hit by that at 20 MPH instead of a full duty lifted pickup with a fresh shiny paint job on chrome wheels (mall crawlers)
I don’t think pickup trucks should be banned. They should be commercial use only. It’s not a family car or a daily driver.
Fuck mall crawlers
And then there is the SUV class. Aka the non-passenger work vehicle family passenger vehicle.
So they passed laws for emissions of passenger vehicles to help with pollution.
These laws force MPG ratings on sedans and SUVs. But they’re looser for trucks.
Car manufacturers realized its also looser since its calculated by weight.
So these fuckers decide to build SUVs on pickup truck frames and make pickups bigger so they don’t have to tighten up the fuel efficiency…
This is one of the main reasons there are so many bigger class vehicles being made now.
Add in all the new LED headlights. Which are too bright because the regulations are outdated based on wattage instead of lumens.
So you have taller vehicles with brighter headlights blinding everyone.
I’m at the point where I’m aiming for a SUV instead of a sedan for my next car…
SeductiveTortoiseIf you dudes want to start over, feel free to copy our regulations. It would also allow you to sell cars here. LED headlights are great, given they keep to regulations.
Best, an European.
Your math is wrong. Kinetic energy scales linearly with mass, quadratically with speed. The graphic you included supports the idea that at same speed, the pickup truck has double the KE. The 120 mph sedan has dramatically more KE than a 30 mph pickup.
Assuming that your sedan has exactly half the mass of the pickup, it would match a 30 mph pickup’s KE at 30*sqrt(2) mph, which is somewhere between 40 and 45 mph.
The energy difference is only really relevant if the thing you’re hitting is significantly heavier or at least similarly heavy like a house or another car. For a person it’s still much worse, but that is moreso because of the high hood of the car.
I know pickup trucks are heavy, but I’m surprised they are 16 times heavier than a Honda civic. The more you learn.
Seth TaylorWell… the person in the last photo looks like they’re not happy about getting hit by a moving vehicle at all.
gizmonicusIf we’re going for efficiency, I think getting hit by both cars is the right move.
There’s quite a large discrepancy between this image and OPs image. This image says the survival rate of 30 mph (48 kph) is 60%, while OP’s image says 50 kph it’s at 20%. I wish they included a source for the data that could explain it.
This is the same issue I take with braking distance scales. They often vary wildly, and some don’t even follow a quadratic increase in distance like you’d expect.
K = 1/2mv^2
TrackinDaKrakenWe wouldn’t have so much trouble with this if all men had the same size dick.
robocall
rnercleI’m guilty of this when using a web browser, I’ll scroll down a page and open relevant posts into new tabs until I’ve accrued several. Sometimes I don’t get to them for quite a while so if I upvote it’s surprising how high the number jumps until I realize it’s sat there for half a day.
I try to refresh when commenting because 9/10 times someone else has already commented the same thing since the internet is dead but sometimes I forget.
I remember a public safety ad being shown that showed the difference in either 30 and 35mph or 30 and 40mph. Was quite dramatic.
Great now do SUVs for the Americans. Go ahead and assume they are not simultaneously being shot at just for the purpose of keeping the simulation simple.
Roads. Cars and busses will be on roads.
Tracks. Trains and light rail will be on tracks.
I’d say both are pretty predictable.
There are also far fewer of them per passenger, so fewer chances for one to come by. They are also operated by professionals who can call in sick if their ability to operate the vehicle is impaired.
A bus could be ten times deadlier in a crash than a car and it would still be safer if it carries fifteen passengers. It could be a thousand times deadlier if operated by a drunk person and still be safer than cars because drunk people don’t operate the vehicle when getting home by bus.
Man I’d hate to be one of the 40 subjects of this experiment
Spoiler/s if that wasnt obvious
Depends on the driver. Also, I think Teslas “FSD” cars are a perfect candidate. Or, hell, Musk would probably do it himself, just for the fun of it.
Mass times velocity equals FUBAR…
But just wait for the deafening screaming of people when 30km/h limits are enacted in front of schools because that would dramatically reduce lethality of accidents, while costing car drivers maybe a few seconds of drive time, if at all. It is quite a spectacle.
I live near an intersection. Drivers will ten second horn blast because someone won’t crawl up the arse of the car in front of them just so horatio can mount the kerb and get into a sliplane they can’t exit until the lights change anyway
So what i’m saying is you’re underselling the stupidity
There’s a new neighbor at the end of our street with small children. She always puts one of those green children at play signs in her front yard, yet insists on driving 25-30mph down our suburban street. The rest of the neighbors hate her.
Baŝto