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Old 2021-01-19, 14:01   #1332
Dr Sardonicus
 
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Quote:
Originally Posted by retina View Post
The part where he is deemed a danger to others is laughable. More likely he is being punished for embarrassing the "security" staff.
Yes, especially since he can be sprung by posting $1000.00 bond. A judge deeming an arrestee a "danger to the community" is often a prelude to ordering that they be held without bail.
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Old 2021-03-01, 17:25   #1333
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OK, the story itself isn't that outlandish, but the headline sure is an attention-getter:

US probing engine fires in nearly 1.9M Toyota RAV4 SUVs
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Old 2021-03-03, 09:29   #1334
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That's why I prefer Mazda :)
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Old 2021-03-03, 22:45   #1335
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Speaking of cars, how do you fit 25 people into an SUV?

https://www.usatoday.com/story/news/...ow/6900800002/

At least 13 of them were 15-53 year olds, so even if you could pull it off, that vehicle would be difficult to move and nearly impossible to steer.

Last fiddled with by The Carnivore on 2021-03-03 at 22:46
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Old 2021-03-03, 22:59   #1336
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Quote:
Originally Posted by The Carnivore View Post
Speaking of cars, how do you fit 25 people into an SUV?

https://www.usatoday.com/story/news/...ow/6900800002/

At least 13 of them were 15-53 year olds, so even if you could pull it off, that vehicle would be difficult to move and nearly impossible to steer.
https://newsroom.vw.com/vehicles/tbt...aking-history/
Quote:
5. Most people crammed into…

A “new” Volkswagen Beetle: A total of 25 people packed into a Volkswagen Beetle in Kremser, Austria on April 29, 2000.
An “old” Volkswagen Beetle: A decade later, a university attempted the same feat — this time with a 1964 Volkswagen Beetle. On December 9, 2010, twenty people crammed into the car, which was the most people to fit inside any old-style Beetle model. A college group organized the event to raise awareness of human trafficking.
A Volkswagen camper van: On September 5, 2015, a group of Volkswagen enthusiasts gathered at a festival held in Malvern, Worcestershire in the UK. Fifty people crowded into the van, setting a record that had never been attempted before, and they used the event to raise money for a children’s charity.
Assuming 50kg per person, that would be 2750 lb. That would be 1000 lb over the recommended max payload for a Chevy Suburban.
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Old 2021-03-03, 23:55   #1337
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An obvious way to make more room inside is to take out some of the seats. I don't know whether this was done with the Expedition involved in the crash.

I leave it as an exercise for the reader not already familiar, to look up the term "clown car."

The effects of the weight of extra passengers on handling a vehicle is an important consideration. Besides problems with getting it moving and with steering, the extra weight would also likely increase stopping distances. And it does appear the SUV ran a stop sign...
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Old 2021-03-04, 01:03   #1338
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Quote:
Originally Posted by Dr Sardonicus View Post
Besides problems with getting it moving and with steering, the extra weight would also likely increase stopping distances. And it does appear the SUV ran a stop sign...
The weight is not so much of an issue for acceleration as the limit for total weight (vehicle and towed vehicle) is much larger. Stopping should not be as much of an issue. The vehicle load limit and trailer without surge or electrical brakes would be within the mass I stated above. Steering, sure, that would be an issue. But, this all assumes a well maintained vehicle.
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Old 2021-03-04, 08:58   #1339
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F=ma
Curb weight 4800 lb empty; ~5000 with a driver
Available acceleration force = rear differential output torque divided by effective tire radius. Torque available won't change with increased vehicle loading. Force does not change much with increased vehicle loading. It may slightly increase due to increased tire deflection reducing the effective tire radius. Perhaps 2%.
Most driving is driver-only in cars, average 2.3 people per van, so that's the driving dynamics drivers are used to.
Add 24 other people at ~150 lb = 3600 lb; subtract ~200lb for the removed middle and rear seats of the Expedition involved; combined mass 8400 lb, so 0-60 time 68% longer than for driver only.
Combined mass is also higher than the sum of the rated front and rear axles' spring capacity, at 3000 + 3900 = 6900 lb; 8400/6900 = 122% of rating. The added load would be biased to the rear, so the rear suspension would have been resting hard on the rubber bumpers at the bottom of spring travel when the vehicle was stationary.
It would be standing room only, except for the remaining 2 front seats, so cg of the overloaded vehicle would be higher than normal, affecting fore/aft weight distribution during accel or decel as well as lateral roll in cornering.

Stopping distance is noticeably longer when towing a brakeless trailer & load combined amounting to ~50% of pickup truck weight. I can feel the changed dynamics effects of a single passenger in my little Honda Insight, a change of ~10% in total mass.

To put that 68% in perspective, it would have felt as if the V8 engine had been reduced to a little less than 5 cylinders. (8/1.68=4.762)

https://www.driverside.com/specs/for...97-2373-4906-0
https://www.beautytohealth.com/avera...men-and-women/
https://www.wisegeek.com/what-is-the...-in-the-us.htm
https://www.hotrodders.com/threads/h...ameter.101007/

Last fiddled with by kriesel on 2021-03-04 at 09:01
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Old 2021-03-04, 17:02   #1340
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Assuming that the brakes exert a constant force independent of how heavily laden the vehicle may be, and cheerfully ignoring other effects of increasing the weight of a vehicle, simple-minded formulas for constant acceleration say the stopping distance from a given speed would be proportional to the total weight.

So if the vehicle weighs 6000 lb with just the driver, adding 24 more people at 100 pounds each would increase the weight to 8400 pounds, and the stopping distance from a given speed would increase 40%. The effects of overloading on the power train, suspension, and tires would likely help bring the vehicle to a halt, but I don't know how much.
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Old 2021-03-04, 17:53   #1341
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F=ma again.
Air drag and rolling resistance help after the driver stops applying power to sustain speed, but are minor contributions.
If the limit is tire skid or ABS performance, vehicle load won't matter much; F/m = a = effective friction coefficient.
Code:
For rubber tyres on cars, the coefficient of friction (μ) decreases as the 
mass of the car increases. Additionally, μ depends on whether the wheels are 
locked or rolling during the braking, and a few more parameters such as 
rubber temperature (increases during the braking) and speed
To which I would add road surface type (concrete, asphalt, gravel, dirt), road and tire texture, and condition (clean and dry, or damp, wet, snow, ice, contains loose sand or gravel or any other debris or liquid)

https://en.wikipedia.org/wiki/Braking_distance
https://www.apps.vtti.vt.edu/1-pager...20Friction.pdf

If the limit is brake fade, vehicle load may matter significantly
https://en.wikipedia.org/wiki/Brake_fade
Bursting rusted weak lines is more likely in an emergency, when a driver applies higher brake pedal force to try to stop as quickly as possible. If the brake lines burst, which is common on very old vehicles not well maintained, or on lines damaged by running over debris, driver recognition and reaction to apply the emergency brake can take considerable time and distance.
On an old vehicle, the cable actuating the emergency brakes may also be weakened and rusted, and break when it is most needed to brake.

In https://mersenneforum.org/showpost.p...postcount=1339 I used 150 lb/passenger, because the link provided there gave 149lb for average Latin American human weight.
1997 Ford Expedition curb weight ~4900 lb https://www.iseecars.com/car/1997-ford-expedition-specs
Gross Vehicle Weight Rating 6750 lb https://www.driverside.com/specs/for...97-2373-4906-0

Just don't overload your vehicle; some interesting photos here

Last fiddled with by kriesel on 2021-03-04 at 18:28
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Old 2021-03-04, 19:04   #1342
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Brake pedal force required for shortest possible stopping distance can exceed the physiological abilities of some drivers. Especially if the power brake assist is weak or absent. https://www.autosafety.org/wp-conten...the-Engine.pdf

Under normal loading/road test, "The Expedition and the Chevy tie for distance in the 60-0-mph test at 142 ft, while the Ford brake system offers by far the best feel of the trio-with virtually no ABS vibration or kickback through the pedal." That's probably distance from pedal actuation to stop, omitting the driver perception, decision, and reaction times (~132 feet at 60 mph = 88 ft/sec). https://www.motortrend.com/news/chevrolet-tahoe-2/
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