Instant Compact F150 (Structure matters!)

Diehard

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I am not sure if human factor has been factored in in any data that is out there. Example not based on real data: Lets assume little ladies are more cautious, buy small cars and drive them conservatively. The mucho men with higher level of testosterone buy big cars and get into road rage more often. Stats may show big cars are involved in more accidents (I am not sure if they are). But are they inherently more unsafe? Even if there is 10% more chance I get in an accident with a big car but 30% more of a chance surviving it, I will still go with the big car.
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Crissa

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I am not sure if human factor has been factored in in any data that is out there. Example not based on real data: Lets assume little ladies are more cautious, buy small cars and drive them conservatively. The mucho men with higher level of testosterone buy big cars and get into road rage more often. Stats may show big cars are involved in more accidents (I am not sure if they are). But are they inherently more unsafe? Even if there is 10% more chance I get in an accident with a big car but 30% more of a chance surviving it, I will still go with the big car.
That is a confounding issue, but...

...the opposite is true.

Per mile, bigger cars get into fewer accidents.
But when they do, the accidents are more damaging.
And they're more likely to kill someone not in that bigger vehicle.

Smaller cars are mostly driven by those younger, with less means and less caution.

The same driver, given a larger vehicle, is more, not less, likely to be in a collision.

-Crissa
 
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JBee

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So which pickup truck or large SUV on the market Today has a stopping distance which is remotely close to the stopping distance of a Smart car?

What is “Possible within the laws of physics” and what is actually in fact real and exists are different things.

Maybe Cybertruck will be the exception.
My argument is not that lighter or heavier cars brake faster, rather that both can brake at the same rate "if" they have the same brake performance and coefficient of friction.

In other words the brakes and friction determine the deceleration rate, if they are both optimised for the mass of the vehicle. It also matters where that mass os on a vehicle as a low center of gravity, suspension setup etc will effect the stopping distance. Simply a comparison of the same car with different brakes and tyres would demonstrate the difference too, given all other components are the same.

To be clear I am not saying that extra mass does not create more braking load, rather that a vehicle can be designed to brake well for any mass. If they are or not is up to the manufacturer. I expect the CT to do well and am hoping they use the new Brembo brake by wire gear.
 

Diehard

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Per mile, bigger cars get into fewer accidents.
But when they do, the accidents are more damaging.
And they're more likely to kill someone not in that bigger vehicle.
seems like we have a social dispute not a technical one. Like the speed, it seems the issue with size is the difference that is the problem.

The problem with freedom of choice is that when you can’t force people to go small, inevitably they go big due individuals tendency for self preservation.
 

cvalue13

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From CR in 2021

Average Stopping Distance by Category
Category Average dry braking 60-0 mph, ft.
Sports/sporty cars 120
Luxury midsized cars 128
Luxury small SUVs 129
Small cars 130
Luxury small cars 131
Small SUVs 132
Luxury large cars 132
Large cars 132
Midsized cars 133
Midsized SUVs 134
Luxury midsized SUVs 134
Compact pickups 136
Minivans 138
Compact electric/hybrid cars 138
Luxury large SUVs 138
Full-sized pickups 140
Large SUVs 143
Average of all tested vehicles 132

So on average between sports cars and full sized trucks, we’re talking a 20ft difference, which is a ~3% difference.

Not to belittle the delta, as perhaps a 3% difference translates to a material difference in velocity at impact. But that’s “sportscar” vs full sized truck.

A “small car” comparison reduces to a difference in 10ft. A minivan comparison is 2ft.

And these are the averages within a class.

The best/worst within classes leave lots of room. The best compact hybrid/electrics [BMW i3 Giga Rex (131 ft.), Hyundai Kona (135 ft.), Kia Niro EV (135 ft.), Toyota Prius (135 ft.)] were significantly off from worst [Ioniq (144 ft.), Kia Niro (143 ft.)], but altogether hybrids/electrics were significantly worse than the compact ICE comparisons:
Best: Kia Soul (120 ft.), Subaru Impreza (124 ft.), Mazda3 (125 ft.) vs Worst: Mitsubishi Mirage (138 ft.), Nissan Kicks (137 ft.), Volkswagen Jetta (135 ft.)

In another test, hybrids had worse stopping distances than their non-hybrid versions, attributed yes to their regenerative breaking tech and of course the weight of the batteries, but primarily attributed to their low rolling-resistance tires employed on the hybrids. Going to show that the friction/tire portion of the stopping equation is material, while also not being inherent to a model.

But bare in mind the “worst” compact car figures above as compared to the best and worst in full-sized trucks: Best: Nissan Titan (131 ft.), Chevrolet Silverado (136 ft.), GMC Sierra (136 ft.) vs Worst: Toyota Tundra (153 ft.), Chevrolet Silverado diesel (144 ft.), GMC Sierra diesel (144 ft.)

Or against the large SUV’s: best: Nissan Armada (133 ft.), Ford Expedition MAX (143 ft.)
vs worst: Toyota Sequoia (146 ft.), Chevrolet Suburban (145 ft.), GMC Yukon XL (145 ft.), Chevrolet Tahoe (145 ft.), GMC Yukon (145 ft.)

Notice that the worst full sized trucks/SUV’s are stopping in the same distances as the worst compact hybrid/EVs, and the best full sized trucks/SUV’s are stopping in the same distances as the best compact hybrid/EVs. I suspect this comes down to the tire type and contact patch friction issues where larger vehicles have the advantage despite their increased weights.

And the worst small cars perform like the best full-sizes trucks.
 


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Ogre

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My argument is not that lighter or heavier cars brake faster, rather that both can brake at the same rate "if" they have the same brake performance and coefficient of friction.
So what you are saying is. Trucks and large SUVs brake slower than Smart Cars.
 

Crissa

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And cheap cars more poorly than more expensive cars, which blurs the numbers.

And all cars are required to stop in about the same amount anyhow, so bigger cars tend to need more expensive brakes.

-Crissa
 

JBee

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So what you are saying is. Trucks and large SUVs brake slower than Smart Cars.
Lol no. I'm saying both can brake the same, if they have the same coefficient of friction on the tyres and the same performance on the brakes.

It depends on the brakes and the tyres, but not the mass.

Simply, per unit of mass you can have the same rate of deceleration, meaning mass is irrelevant.

But... in the case of the smart it has better brakes, and comparably probably better grip on the tyres, so it brakes a bit shorter distance. The better brakes and tyres can also be a factor of cost, in that the smaller parts are comparitively cheaper to oversize.

As cvalue13 pointed out above, the differences between the classes is not that much, despite some vehicles weighing twice as much as others. That should be enough "evidence" to show that mass isn't the most dominate factor in understanding braking distances.
 
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Qball

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Well, maybe no mid-gate isn’t such a horrible idea after all. I’ll settle for rolled down mid window.
 


cvalue13

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Lol no. I'm saying both can brake the same, if they have the same coefficient of friction on the tyres and the same performance on the brakes.

It depends on the brakes and the tyres, but not the mass.

Simply, per unit of mass you can have the same rate of deceleration, meaning mass is irrelevant.
the points both you and @Ogre are making might be better resolved with an analogy to acceleration

0-60 acceleration times do “depend” on a specific vehicle’s mass, in the same way a vehicle’s 60-0 stopping distance “depends” on its mass.

But the vehicle’s ultimate 0-60 acceleration (despite or considering its mass) will be determined by its engine/transmission performance relative to that mass, in the same way that it’s 60-0 stopping distance (despite or considering its mass) will be determined by its break/tire performance

Takeaway and emphasis for @JBee seemingly being that these vehicles’ stopping distances are not predetermined by their mass; they are engineered to accelerate in a given distance despite their mass, just as they’re engineered to stop in a given distance despite their mass.

Takeaway and emphasis for @Ogre seemingly being that, accepting that above point, the frictions of engineering costs mean the market generally produces vehicles that still reflect their mass in their relative stopping distances.

to me, the data from CR above shows how you’re both equally right. The averages for a class prove up @Ogre’s point, while the variance within and compared across classes proves up @JBee’s point.
 
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Ogre

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Everyone is missing the most vital datapoint. If I operate the vehicle, data shows ZERO fatal accidents.
Well you certainly have a track record of zero driver fatalities while you are at the wheel.

How many innocents you’ve mowed down is less clear from this side of the forum.
 

BigAl

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Sooo what I'm getting out of this last part is that a Hummer EV can stop just as fast (same stopping distance) as a Smart car.... GOT IT!!!o_O:oops:
 
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Ogre

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the points both you and @Ogre are making might be better resolved with an analogy to acceleration
My point is simply that what is possible does not reflect reality.

It is possible every baby born in the past 24 hours was male. I’m pretty sure that did not happen, but it is possible. JBee lives in this land of hypotheticals.

If we are talking about vehicle safety, we are by definition talking about actual driving vehicles on the road. Nobody has ever actually died in an auto accident in the land of hypotheticals.
 
 




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