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      12-10-2009, 04:49 PM   #1
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Pedestrian Safety design?

I keep hearing that the more vertical front of the new designs are for meeting increased pedestrian safety regulations. Can someone explain the reasoning behind this? At first thought, I would rather be hit with an e92 than an F01....

I would rather be ramped up onto the hood and flung over the car than have that 90 degree slab of a nose sever my legs and leave my dead torso to fly straight through the windshield.

But seriously, is it meant to spread the force over a wider and flatter area?
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      12-11-2009, 12:03 AM   #2
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I'm curious too. I never understood this. I feel like the new design is meant to run you over instead of toss you up
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      12-11-2009, 12:05 AM   #3
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Curious about this too.
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      12-11-2009, 12:23 AM   #4
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lol there is no such thing as pedestrian safety design at 30+ mph
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      12-11-2009, 01:44 AM   #5
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This is X1's



Nono your legs are fine, it's your pelvis that gets crushed

Tbh i'm curious aswell ...
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      12-11-2009, 06:01 AM   #6
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interesting
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      12-11-2009, 06:08 AM   #7
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I've been trying to sort out what the new standards really are . From what I can figure out, the front has to be flatter so that you knock the pedestrian or bicyclist down so you can run them over and squish them rather than have them fly over the hood into your windshield, causing more damage to your car for insurance companes to pay for. is this right?
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      12-11-2009, 10:09 AM   #8
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Quote:
Originally Posted by wrickem View Post
I've been trying to sort out what the new standards really are . From what I can figure out, the front has to be flatter so that you knock the pedestrian or bicyclist down so you can run them over and squish them rather than have them fly over the hood into your windshield, causing more damage to your car for insurance companes to pay for. is this right?
Maybe that's BMW's master plan to get pedestrians away from roads and into cars.
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      12-11-2009, 10:48 AM   #9
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The current e92 design flings people up 20 feet into the air which is a little bit too high so they need to make it flatter so the pedestrians won't go so high

http://www.liveleak.com/view?i=f4d_1248219900
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      12-11-2009, 01:29 PM   #10
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Besides pedestrian can potentially get lifted high in the air, the massive speed of impact may cause hood to flip over and block driver's view after the impact. This usually happened to design/style with bonnet meets top of kidney grill (e.g. E60, E90/92), where the hood latch was said to be the weakest link. But then, the new X3 (F25) bonnet line may follow the similar design judging from latest spyshot. It's a bit of marketing decision IMHO.

While the design of bonnet line across the hood was nothing new from BMW design history, if there is an option, I'd preferred E39, E46, and E70 X5 hood style where the hood continues on kidney grill.

Bonnet line across the hood looked pretty sleek (e.g. F01 7er, F10 5er, E89 Z4, E84 X1, E52 Z8, and E31 8-Series to name a few).

e.g. E31
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      12-12-2009, 03:03 PM   #11
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So the reason that the bonnet has that split at the front is to accommodate the fact that on impact the whole lid of the bonnet is raised like an airbag to cushion the damage of the head hitting the bonnet and then then engine or bottom of the windscreen.

It is now a legal requirement for all newly designed cars made in Europe to follow this safety legislation.
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      12-13-2009, 02:33 PM   #12
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Quote:
Originally Posted by simnew View Post
So the reason that the bonnet has that split at the front is to accommodate the fact that on impact the whole lid of the bonnet is raised like an airbag to cushion the damage of the head hitting the bonnet and then then engine or bottom of the windscreen.

It is now a legal requirement for all newly designed cars made in Europe to follow this safety legislation.
cool, they should have spend the money on good driving education and testing though... too many immigrants that get them for free in europe because they had one lying around from back home
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      12-14-2009, 12:51 AM   #13
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IMHO... pedestrians can suck it... they gotta watch out for drivers not the other way around...
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      12-14-2009, 01:53 PM   #14
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Quote:
Originally Posted by simnew View Post
So the reason that the bonnet has that split at the front is to accommodate the fact that on impact the whole lid of the bonnet is raised like an airbag to cushion the damage of the head hitting the bonnet and then then engine or bottom of the windscreen.

It is now a legal requirement for all newly designed cars made in Europe to follow this safety legislation.
+1, Last month's Roundel had a great write up on it. I'm going to add that there are additional rules requiring the hood to be 'X" amount of airspace bewteen it and the engine. The lack of protruding bumper also has an effect upon how a pedestrian hits the hood not to mention lessen the chance of broken legs.
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      12-28-2009, 05:34 AM   #15
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The flatter front bumper of the car means that when the bumper hits the pedestrian's leg, the contact area is bigger and the force is spread out. The force per contact area (e.g. lbs/in) exerted on the leg is reduced and so are injuries. At really high speeds, it won't matter but at lower speeds it'll help.
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      12-28-2009, 08:00 AM   #16
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I have decided that it means when the car hits you, it breaks your hip, not your knees
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      12-28-2009, 09:40 AM   #17
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Quote:
Originally Posted by my92 View Post
The current e92 design flings people up 20 feet into the air which is a little bit too high so they need to make it flatter so the pedestrians won't go so high

http://www.liveleak.com/view?i=f4d_1248219900

young fukwits racing at illegal speeds in expensive cars at night. these people should be castrated so that they no longer have a need to measure up against each other on public streets.




As for the topic, may be this will help you.


In a nutshell, they found out that this knee-bend accidents cause many fatal injuries and want to change that by making changes to front of the car (thicker bumpers, deformable headlights, higher bonnet line). They also propose going forward to almost do away with such a thing as bonnet and just allow drivers access to replace fluid areas. If there is no bonnet, there is possibility to package things more closely and away from car's bonnet, and thus create more padding and make front of safer materials for pedestrians. They still debate on it but the framework is there and manufacturers alone are starting to tackle the issue as it's a major cause of death in road accidents (head on hit).

Quote:
Designing for Pedestrians in Impact

In direct response to proposed and actual EU legislation, manufacturers are trying to stop pedestrians impacting with hard-points at the front of vehicles. The principle responses are to either raise the bonnet to a stance that better absorbs energy, or to use airbags to cushion against these hard-points. Although these approaches offer a way to maintain existing styling traits, they are unlikely to be as simple or effective as more dramatic changes in vehicle front design.

In 2000, 28% of UK road fatalities were pedestrians. Key improvements seem to revolve around giving the right amount of support, in the right areas, to a pedestrian in impact. It is suggested that bumpers have a deeper profile or a support structure below the surface to reduce “pitching of the leg-form and bending of the knee joint”. ‘Foam plastics’ could be used to absorb the energy of the impact as they possess good ‘recovery characteristics’ to reduce permanent damage to the vehicle in “low-speed car-to-car collisions”.

At the leading edge of the bonnet it is desirable to reduce the stiffness of the structure and avoid the location of catches and other fixings close to the surface. Bonnet reinforcing structure and panel seams add to the number of risk areas for impact. Statistics by the (UK) Transport Research Laboratory predict design improvements could prevent 8% of all pedestrian fatalities and 21% of serious injuries. The UK Department of the Environment, Transport & the Regions (DETR) is more optimistic, believing up to 20% of pedestrian fatalities could be prevented within 8 years.


Several key changes to design can be considered as a means to improve pedestrian impact performance:

* Bumper foam needs to be 20-40mm thicker than on current vehicles and may need to be bigger in the vertical direction.

* “A low level foam-covered beam is needed to reduce rotation of the knee joint. This could be disguised under a spoiler-style skin..”

* Lights should be kept below the upper leg crush zone or designed to deform in a controlled way.

* Under bonnet clearance should be at least 75mm, with special consideration paid to major features such as shock absorber mounts. Some suggestions have been made that double-wishbone suspension may be an alternative - this depends on the packaging in this area.

There is some difference of opinion on bonnet leading-edge height. Some sources state that anything above 650mm in height is undesirable where other point out that “making the hood edge height higher is effective in lowering the vehicle-head collision speed”. It is noted though, that “if the edge of the hood is too high, it might be dangerous for children because their heads might be directly hit by the front of the car”. They chose 800mm as a suitable height as it is lower than the head of a 3 year old child. There is no defining conclusion on the subject of leading edge height; it makes more sense to look at reducing hard points, improving controlled plastic deformation to absorb energy and stiffening lower bumper structure to minimise leg injury.

In tests on bonnet structure, it was concluded that steel, backed with a ‘soft foam elastic material’ performed better than any other metal-based structure. No solely polymer structures were tested. Traditional bonnet design involves dangerous points of reinforcement and its performance in impact is very difficult to predict or control.

Modifying existing methods of manufacture to improve pedestrian impact performance may not be the ideal direction to take. It should be noted that bonnet clearance needs are different for children and adults, that clam-shell bonnets are preferred, that simply raising everything for greater clearance over componentry will increase drag and thus fuel consumption. Existing vehicle structures cannot produce uniform responses to impact and some common practices - such as the use of MacPherson strut suspension - are almost incompatible with long-term improvements in this field.

Headlight design may also need to change. The front of the headlight could become part of the passive safety system, where the lens will be collapsible and packaging requirements will alter as the lighting unit is moved back from the likely point of impact.

Bonnets

Looking specifically at the bonnet area, user intervention in the engine bay area is constantly decreasing. In fact, with current levels of reliability, most users need access to the engine bay only to replenish items like the screenwash. Given that the bonnet is simply a reinforced sheet metal lid on most vehicles, why not separate access to the engine from that of the replenishable fluids? Access to these items could be tidied away to a more convenient place. This would allow the bonnet to be replaced by simpler, stiffer structure that could save weight or be used more efficiently in dissipating the energy of an impact.

With the bonnet replaced by a stiffer structure, it may then be possible to create a more efficient body using fewer and lighter materials. The result would be a vehicle that weighs less, requires less energy to propel and impacts with decreased momentum; ideal characteristics for a safety- and environmentally-conscious vehicle. If access from above is not required for most major engine bay components, it is then feasible to more densely package them, moving all major hardpoints even further from areas of pedestrian impact as well as reducing the vehicle’s footprint.

Bumpers

Research into bumper development used ‘special energy absorbing elements’ made of PolyPropylene under a PolyPropylene skin to achieve a balance in impact performance across the bonnet leading edge, bumper and spoiler area. Although an ideal vehicle front “is not completely achieved by choosing special material properties only”, the only firm suggestion relating to styling is that features creating high local stiffnesses should be avoided.
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      12-28-2009, 10:10 AM   #18
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probably wrong sense of humor, but the whole points thing was pretty funny to me. 16.6 points for hitting the pedestrian's head.

back on topic, well i guess things like this works great for places like NY where people just cross whenever they want to, and not look at cars
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      01-09-2010, 05:41 PM   #19
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as far as i know, bmw's are built to protect the people inside, not anyone else.... they are poor when it comes to pedestrian safety in quite a number of vehicles, but it doesnt bother me.... lol
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      01-20-2010, 11:31 PM   #20
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I guess there's only one way to find out...

Quote:
Originally Posted by Shazmonkee View Post
I'm curious too. I never understood this. I feel like the new design is meant to run you over instead of toss you up
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      01-21-2010, 12:35 PM   #21
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I guess that's part of the reason why the new 7 looks funny up front.

That 8 series is hot, by the way!
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      01-21-2010, 12:37 PM   #22
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From what I understand, the majority of car vs. pedestrian accidents occur in the city at less than 30 mph, most resulting in death from a head injury.

The current design results in the car pivoting the person at a high rate of speed, with the head slamming into the hood of the car first.

This design, along with a larger gap between the hood/engine, will reduce the amount of head injuries hopefully.
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