Video: 50mph BMW 535i vs. Volvo 960

[SC David]

Check it out guys, there's obvious advantages to both cars, but guess who comes out victorious...

http://auto.joins.com/upboard/pds/pdst/2004060135562_BMW%205%20Series%20vs%20Volvo%20960. wmv

[ryan roopnarine]

i have yet to get it to play all the way through, and i've downloaded it 3 times, looks interesting though.

[Unregistered]

Wow!!! Don't really know what else to say! Thank you!

[ryan roopnarine]

wowie wow wow! it shows their inherent pro-swede bias, clearly the bmw is still good and serviceable! i coulda got thru that with minimum damage :p clearly, the bmw won though, its obvious :D


ps....though it would have been nice if you had warned dl'ers that it was 50 mb, it was worth 4 dl efforts!

[ryan roopnarine]

jesus.....its like i have a fetish for the video or something...i've watched it like 20 times now, the slow speed money shot....cutting action like butter. oh, and if it were a m50 car....well then, they would have just have had to buff out the bmw, as the plastic intake manifold is a safety device :D

[DueyT]

Ouch!

Interestingly, if the vehicles have the same mass, then conservation of energy and momentum says this would be the same as slamming into a stationary wall at 60mph as well... Neither is a very interesting prospect! =:-o

Duey

[shortbuss2336]

thats a cool video, one of my favorites!

[bahnstormer]

is this from top gear?
i have that full episode

[Craig]

Ouch!

Interestingly, if the vehicles have the same mass, then conservation of energy and momentum says this would be the same as slamming into a stationary wall at 60mph as well


I think you mean 120mph. Even worse.

[632 Regal]

Holey ****!

what a scene

[DueyT]

I think you mean 120mph. Even worse.No, 60 mph relative to the inertial frame of reference within wich the vehicles are being considered. While it is true that their closing speed relative to each other is 120 mph, this is not at all equivalent to one vehicle standing still, and the other hitting it at 120 mph.

Conservation of energy proves this. Let's say v (velocity) = 60 mph, and both cars equally weigh mass, m. Total kinetic energy just before collision is:

Car 1: K.E. = 1/2 m * v^2
Car 2: K.E. = 1/2 m * v^2
Total: K.E. = m*v^2

If someone said that's like one car hitting a stationary car at 120mph (2 x 60mph or 2v) the energies would be:

Car 1: K.E. = 1/2 m * (0)^2 = 0
Car 2: K.E. = 1/2 m * (2v)^2 = 1/2 m * 4v^2 = 2m*v^2
Total: K.E. = 2m*v^2

m*v^2 does not equal 2m*v^2, so the 120mph effective impact (Energy wise) is not a valid construct.

To make the conversation more intersting, when do you steer for a wall and when do you still hit the oncoming car?

Conservation of momentum (product of mass times velocity, mv...not kinetic energy, 1/2mv2) makes us consider the head on vice wall crash carefully. If you have greater momentum than the other car, then you are better off hitting it, than a concrete wall. Your greater momentum means you will slow down less than the other vehicle...which would actually reverse direction of travel. The difference may be slight, for example, say your car weighs 3500lbs and the oncoming vehicle weighs 2500 lbs. Calculating conservation of momentem, you would slow from 60 to 10mph, a -50 mph change, while the other guy would slow from 60 to 0 then be pushed backwards by you at 10mph opposite to his original travel...overall change of 70mph vs. your 50mph change...ouch!

Now, if the vehicles have the same mass... then both come to 0 mph...exactly as if you had hit a wall (interesting!)

OK, what if you have less mass (against say, a Brinks armoured truck full of coin!)...now you're heading backwards and you would have been literally better off hitting a brick wall.

Interestingly enough, a wall (or other unyielding structure) is actually a fully variable force structure...if strong enough (so it's structuraly integrity is not compromised) it will "push back" against the car with "just enough" force to counter the car's energy...perfectly! No less (or it would yield, crumble, chip, etc... and the car would continue forward) and no more (otherwise the wall would actually "push" the car backwards after the collision.)

Food for thought...


Cheers,
Duey

[Craig]

Duey-

Great proof! Never thought to actually work it out, I always just ASSumed. Neat, thanks!

BS Physics, University of Washington 1998 :D

[henryw525i]

I reckon the rear seat passengers in the BMW would have been "alive" It was an M20 525iA with newer version gauge cluster...and cruise control.

Daym I wish I lived in the UK and could buy one for a grand!!!

[DueyT]

The frontal quartering (a.k.a. offset frontal) impact is one of the worst out there...well, aside from being T-boned.

Any greater overlap between the cars and both engines would have submarined below the body and both frame rails of each car would have more evenly absorbed/disappated the energy.

Not that either car was in good shape, but I think the BMW still did slightly better... Now if they did a head-on collision test with a BMW (or Volvo) with, say a 2004 Chevrolet Cavalier...the meat-wagon would definitely be pulling up to the Chev.

Cheers,
Duey

[Brian C.]

:D :D :D

Luckily I just take photos at the crashes I go to. The Traffic Investigation Guys are the ones that do all sorts of skid and vehicle weight calculations. There's actually one old guy who's been doing it for 30 years who still uses a slide rule! Hey.....if it works....

Brian C.

[DueyT]

Brian, do your TCI guys have TotalStation? That's a real sweet setup...it backs up the slide rule really well. My buddy loves it because he can survey a scene literally in a few minutes...that sure beats hours with a 100 yd measuring tape!

p.s. Do the guys think that the Cavalier/"Death-fire" (a.k.a. Sunfire) are vehicles you might want to stay away from?

Cheers,
Duey

[Dan in NZ]

I haven't actually watched the video, screw downloading 50mb... But if the BMW was in "better shape" visually, would that mean it's structure has deformed less, increasing the rate of deceleration, meaning greater injuries to the occupants? Assuming equal vehicle masses etc etc etc.

[rickm]

They didn't seem to focus too much on the rear seating, but if you were sitting up front in either car you'd now resemble chopped clams. :D

Dan: the Volvo ended up on it's roof, the BMW rolled once. The top of the BMW looked ok (anyone want a sunroof?), the Volvo you couldn't see. I wish the Volvo was a lighter color so you could see more details...that burgundy blended all too well with the undercarriage (though i'm sure the video compression didn't help). Either way that was a nasty wreck. I want to see a 7 series against a Ford Festiva. :D

An hour of these videos would make a great PPV. Or some good material for the driver's ed classes.

[Brian C.]

...The Traffic guys use it a lot and seem to think it's just peachy, but the Crime Scene Guys in my office like to refer to it as Total Waste of Time. I think it's better suited to large scenes like roadways and intersections as opposed to inside a house or building. It's one of those toys that the CSIB people all roll their eyes about when somone asks if they've "total-stationed" the scene yet. I've never personally used it. In an interior scene they have laser-tape measures that will give them interior-to-interior wall dimensions, and then they do a rough sketch. Then they will do a more thourough scale drawing back in the office. 75% of these people have been doing this same job for 10-20+ years so they are not too conducive to new things. I know that the TS data can be downloaded to a CAD plotter and do a drawing that way but they don't do that here yet. And if you get your scene done too fast, the overtime is'nt adding up as quickly! :p

Brian C.

[Hector]

I remember COE and COM being shoved down my throat cuz I think the prof had a relative who analyzed distance traveled of totaled cars in traffic accidents and such. So we ate this stuff 3 times a week for a month!! I can still taste it :o)


No, 60 mph relative to the inertial frame of reference within wich the vehicles are being considered. While it is true that their closing speed relative to each other is 120 mph, this is not at all equivalent to one vehicle standing still, and the other hitting it at 120 mph.

Conservation of energy proves this. Let's say v (velocity) = 60 mph, and both cars equally weigh mass, m. Total kinetic energy just before collision is:

Car 1: K.E. = 1/2 m * v^2
Car 2: K.E. = 1/2 m * v^2
Total: K.E. = m*v^2

If someone said that's like one car hitting a stationary car at 120mph (2 x 60mph or 2v) the energies would be:

Car 1: K.E. = 1/2 m * (0)^2 = 0
Car 2: K.E. = 1/2 m * (2v)^2 = 1/2 m * 4v^2 = 2m*v^2
Total: K.E. = 2m*v^2

m*v^2 does not equal 2m*v^2, so the 120mph effective impact (Energy wise) is not a valid construct.

To make the conversation more intersting, when do you steer for a wall and when do you still hit the oncoming car?

Conservation of momentum (product of mass times velocity, mv...not kinetic energy, 1/2mv2) makes us consider the head on vice wall crash carefully. If you have greater momentum than the other car, then you are better off hitting it, than a concrete wall. Your greater momentum means you will slow down less than the other vehicle...which would actually reverse direction of travel. The difference may be slight, for example, say your car weighs 3500lbs and the oncoming vehicle weighs 2500 lbs. Calculating conservation of momentem, you would slow from 60 to 10mph, a -50 mph change, while the other guy would slow from 60 to 0 then be pushed backwards by you at 10mph opposite to his original travel...overall change of 70mph vs. your 50mph change...ouch!

Now, if the vehicles have the same mass... then both come to 0 mph...exactly as if you had hit a wall (interesting!)

OK, what if you have less mass (against say, a Brinks armoured truck full of coin!)...now you're heading backwards and you would have been literally better off hitting a brick wall.

Interestingly enough, a wall (or other unyielding structure) is actually a fully variable force structure...if strong enough (so it's structuraly integrity is not compromised) it will "push back" against the car with "just enough" force to counter the car's energy...perfectly! No less (or it would yield, crumble, chip, etc... and the car would continue forward) and no more (otherwise the wall would actually "push" the car backwards after the collision.)

Food for thought...


Cheers,
Duey

[SC David]

Sorry about those technicalities guys, I myself get a tad annoyed when people give the wrong info. The first time I watched the video I was in a library with highspeed broadband and I couldn't use sound. I just guessed the bimmer was a 535 since I tend to see those with basketweaves and 525's with the bottlecaps. Speed looked to be around 50mph.

[SC David]

Actually, now that I look at the engine, it is indeed that of a 535i. Take a look when the time is at 5:13. That's definitely the block of a 535i, unless the look of the 2.5L engine changed after 1992. Tiff may have made a slight mistake.

[andyman32]

WOW that was a hell of a video... and it hits right at home too! (check footer)

he said he got that E34 for $1k? Meaning 1,000 pounds or 1,000 USD? Still... 1,000 pounds isn't very much. Probably couldn't even get a running E34 for that in the U.S. At least, none that I've seen - not without collision damage.

[ryan roopnarine]

the europeans had the m50 motor by 1990 model year, so I think its gotta be 89 or 88 vehicle...that's the soviet lookin' :D m20 intake manifold, like you've got. i know that top gear was already on the air in 1994 (possibly earlier) so it might be an 88 or such.


Actually, now that I look at the engine, it is indeed that of a 535i. Take a look when the time is at 5:13. That's definitely the block of a 535i, unless the look of the 2.5L engine changed after 1992. Tiff may have made a slight mistake.

[DueyT]

Brian, I thought TS was made for TTCI work (tech traffic collision invest), not for general crime scene work? If so, nowonder the CSIB complains about it...they're potentially misusing it, no? I just saw a recent crime scene reconstructor that uses LIDAR (laser radar of sorts) to rebuild any type of spatial scene into a 3-D CAD file. It has pretty good resolution and even gets a bit of colour into the scene's file. I think the FBI is one of the few orgs using it at this time.

Cheers,
Duey

[Brian C.]

...but the one my office uses is very much like a surveyor's transit and a reflector on a pole, hooked to a laptop sorta thing. I'm sure it's pretty much what you're talking about. My guys don't really use it inside smallish spaces, but they may...(notice I say *may*)...take it out if a crime scene is rather involved. Many times we will get a complete cluster-f!@k with some sort of Police-involved shooting. Maybe a 7-11 robbery gone bad that went out to the parking lot or became a pursuit.There may be an extended area outside with numerous casings, blood drops and whatever laying around that can be plotted easily.

Now that I think of it, the last time I know that it was used for a crime scene was about two months ago when a little sh!thead and his girlfriend were breaking into cars in a lot and the 75 year old Security Guard tried to stop them. He had his gun on the kid when the girlfriend got in their car and sped around the lot. She pulled up to pick-up the kid and in the process ran over the old guy. The kid just yelled "Floor it!" and she took off dragging the guard down the road, around two corners and finally back to the lot. He was dragged almost a mile under the car. They plotted the drag marks and where all the various chunks had fallen off of him and the skid marks where she tried to dislodge the body. Nice kids, huh. I just took the aerial photos the next day, but when they finished their drawing, it was remarkably accurate to the photos.

I know there is so much new equipment on the market today that it would fill four vans for each one we have now. In fact I got a call last month from some salesman who wanted to demo some sort of 3-D room scanner. When there is so much continous work to do, and when the people who do it have been on the job for many years they get a routine down that they don't like to break sometimes. So much of the new technology is great, but if you give scanners and plotters and fancy stuff to people who have trouble burning CDs, it won't always make their jobs easier. But the Traffic People like it.

OK, here are my equations for it:

W x OT = X$

...as in "The amount of work to be done, times the available overtime, will produce a paycheck of relative size."

...BUT...

TS(u)/time = x(BRASS)/#TV

...or, "Total Station's use in time is directly proportional to the number of Bigshots on scene in relation to the amount of TV cameras."

...or something like that...
:p

Brian C.
(all I remember from physics is F=MA!)