How does driving heavier cars help prevent accidents?

Question

I read an article that said by increasing a cars weight by 100 pounds it would help save highway fatalities. Why is this true?

Answer 1

Normally more weight means more metal to protect you from a accident. More weight means that the car won't skid as much and the heavy the car the better the tires hold to the road.

Answer 2

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Colin Chapman (Lotus Cars/Racing Team): One of the most admired engineers in automotive and racing history stated "if you are going to add anything, add lightness".

Maybe it's a hundred pounds of bubble wrap or a similar shock absorbing device?

.

Answer 3

I don't know the article you reference, but I can only assume that they were speaking of adding more structure where it counts in an accident.  I doubt that the extra weight was intended as ballast - to increase braking, because the extra weight would make breaking less effective!

If there is another physically valid reason, it's beyond the five years of physics I took in college!  

PS:  Don't go buy bags of sand and put them in your trunk...unless you're trying to get better traction in the snow.  The extra weight won't help in a crash!  ;o)

Have a fabulous day!

Your friend in Seattle.

Answer 4

I agree...weight is simply not a safety barrier. Heavier cars are more prone to skidding (simply due to inertia), they require more active braking (simply, you have to break quicker and earlier for the same effect), they tend to be less responsive if you need to swerve to avoid something (inertia again)...also, if they are higher, as some like 4X4s are, the higher centre of gravity means they're more prone to rollovers.

Be careful too of extra weight in your car - especially toward the back. Cars act around an invisible "axis" called the centre of gravity - think of it like a pole, vertically through the middle of  your car, that it spins around - sort of like being skewered! If you keep all weight in balance, the movement around the C of G will be even - but too much weight either side of it? That side will tend to lag or slide out more...for instance, if your trunk/boot is full of weight and you lock up the wheels in a slight turn, you have much more chance of the car spinning out (the boot leading the way!) than if there's no weight in there...

For safety, you are better to go with a smaller, lighter car - and look for these features.

ESC - electronic stability control. This is a computer driven system that helps maintain control of all four wheels individually during a sudden move (such as a swerve) and prevent the wheels locking up - and you sliding or losing control...

ABS - anti-skid braking system. Similar to ESC but different - ABS works on the brakes by applying and releasing them in a very, very, very fast on-off-on-off motion - this grip/release tactic basically works to allow the car to brake - then the release means the wheels don't have the opportunity to lock - they can regain road grip (by moving) then braking again.

Crumple zones - these are specialist zones designed in the car, like the name suggests, to crumple. I know that sounds dangerous - and when they're crumpled, a crash looks a lot worse - but interestingly, through the physics of it - guess what? the crumple zone makes it a lot safer! The way they work is like this. The cabin is reinforced...while the rear and front of the car are designed to crush up easily and fall away (downwards, away from your feet) in a crash. So if something hits hard head on, the motor will crumple and actually absorb the force by crushing up - and the cabin will survive. Older cars that don't have this tend to have the engine pushed back into the cabin and the dash collapse onto the front passengers.

Seatbelt G-force limiters and pretensioners. These little toys are often forgotten and never mentioned - but they're built into the seat belt. In the split second of a crash, the pretensioner will tension up the belt - and hold you rigid against your seat, to reduce the risk of you hitting your head. At the same time though, the G-force limiter will activate and in microseconds, will release then re-activate the seatbelt tension. What that does is mean you are held back but in the milliseconds you are pushing hard forward on your belt, it is releasing the pressure across your body a bit - so it reduces bruises, broken collarbones and the like... :-)

Airbags - fairly common knowledge...basically in place to absorb head impact. New side airbags are out now - I can't recommend them enough - because in a side impact, your head simply goes sideways - a steering wheel airbag won't help at all...but now, these save you hitting the windscreen.

I'm a fire and rescue volunteer...I go to car accidents and cut out people with the jaws of life. I'm always amazed...at simply how much better off people with these systems survive in a crash. The car (esp. with crumple zones) might be absolutely smashed - but the people are hardly hurt (just trapped!).

In fact its sad...because I might go to an expensive, heavy 4X4 or SUV crash...and people are in a horrible state because they sacrificed the cost of safety systems for a fancier, bigger, heavier car. But those in a smaller, newer car get out so much better off...

Hope I helped a bit! :-) and didn't scare you too much!

Answer 5

Whoever wrote that is full of you no what!!!!!!!!!! 10 gallons of gas weighs that much. Why dont they just say drive with a full tank and it will save lives. Ya whatever!!!!

Answer 6

Heavier vehicles don't "prevent" accidents, they increase the chances of survival and reducing injuries in the event of an accident.

Answer 7

will not skit when breaks applied all of a sudden ...

stable

:p

im not sure...

Answer 8

Ridiculous, unless someone is looking at an older car with no modern safety features, such as airbags, intelligent seatbelt mechanisms, shock-absorbing panels, traction control, and passenger protection cages (best example is the safety cage of a Smart car).  If a Ford F-150 and a Mini-Cooper are each driven into a concrete wall at 40 mph, both drivers wearing seatbelts properly, the driver of the Mini will be checking to see if the driver of the F-150 is alive, and calling for the ambulance.  That is one of the best proofs that smaller and lighter is not necessarily less safe, and heavier and larger is sometimes much more dangerous to be in.

Answer 9

total bullS*it. the only way to prevent accidents is to drive defensively. know where you're going. limit distractions. obey speed limits and pay attention to your surroundings

Answer 10

You should cite the source, so we can give a full critique. By the laws of physics, heavier objects gain more momentum, and therefore...take longer to stop.

Heavier vehicles (like those seen in the mid-20th century) help protect drivers. Preventing accidents should be contributed to safer drivers and better road engineering.

Answer 11

They don't and I would like to see the link for that article.

Answer 12

You herd something that makes no sence.  I'ed listen to the idea but I doubt I would believe it.  Weight has little to do with safety.  Its Structual integrity and energy absorbsion the crushing of the car WITHOUT getting in your space in the cars interior,  thats the trick to a safe car

Actually if its a really old fully framed HEAVY car its a death trap.  When your in an accident you WANT the car to crush up to absorb the enegry NOT YOU!!!..  With a heavy strong body fully framed car you body is stopping faster then it can handle to live. at any speed above say 20 30 MPH.  When a car is being crushed up like a tin can its sowing down before  you are.. What you want is a LARGE UNIBODY car. A UNIBODY car is a car where MOST of the body is the actual frame.  Framed cars have a actual box uner the car that the body bolts on to.

Answer 13

It doesn't. Heavier cars do not prevent accidents.

They are more difficult to handle, their kinetic energy is much higher as it's proportional to their weight (kinetic energy = (with little simplification) speed x weight), they require more power to stop, their braking distance is longer.

They are more dangerous when they skid.

More metal usually increases protection of passengers, as it absorbs more energy generated in a crash, but again, with a little sophistication you can built a small car that's much safe than a truck!

Little Mazda2 is SAFER than Nissan Frontier!

Mazda2 got full 5 star rating in European NCAP crash tests easily equalling much heavier competition in its class. It weights less than a ton.

Nissan Navara (pick-up truck know as Frontier in the USA) scored a single point and basically failed the test.

Answer 14

There is one thing, and one thing only, that can help prevent accidents... and that is the driver behind the wheel.  They cause them... they can prevent them.