New Road Safety Measures

[Christophe]

Ah yes now I understand everything, thank you Gaston and Fakir

[gegyx]

Front shock between car and bike ...

http://sports.nouvelobs.com/cyclisme/ar ... ?coverhome

Does the cyclist take almost all of the energy from the 2 vehicles?

[Christophe]

lol gegyx no it's not going "fast enough" to hurt the car ...

While we're at it: how much should an 85 kg bike (all inclusive) go to have the kinetic energy of a 1200 kg car traveling at 40 km / h?

Response: 42 m / s or 150 km / h

Well, I would have thought more ...

[chatelot16]

in the case of the bike that fits into an oncoming truck fortunately the cyclist does not absorb the energy of the truck ... the truck will be just a little slowed down by the energy it gives to the cyclist

but the shock does not make it pass from the speed of the cyclist to zero speed: the shock makes it pass from its speed of cyclist to the speed of the truck in the other direction: the sudden change of speed is indeed the addition of 2 speed ... the energy to dissipate for this speed change is to be calculated with this addition of speed

[Christophe]

the cyclist does not absorb the energy from the truck ...

Not all but part of the energy from the truck is necessarily transferred to the cyclist ...

It would be interesting to estimate the G taken by the cyclist who goes from 25 km / h to -40 km / h in ... how many seconds and to know if the damage is more during the impact on the ground or against the other vehicle ...

This subject deviates well in "physical sciences of the accident" but I like lol

[Macro]

I had the 240kg motorcycle experience plus driver from 75 to 15km / h right through a kangoo at speed 0 ... Not good to see the kangoo ... My deformed helmet was on display at the local office of the bikers' mutual for a while ... With the mention: imagine if he hadn't worn it ...
It is well known that on the 75kgs of a biker there is 40% in the head (well what the big mouth is part of the head) 30% in the balls .. (if if the tank of the ninja has tasted at this level). and 20% in the right wrist (only traumatized this time) .. The remaining 10% is the rest of the body ...

The back of the kangoo has moved about XNUMX cm (according to its driver)

[chatelot16]

we can measure the g in a moderate acceleration or deceleration, when we do not deform: in case of shock the notion of g no longer means much

in the event of impact against a solid wall, the first piece of sheet metal which touches the wall takes an infinite number of g since it passes at zero speed instantaneously

then the more scrap there is to deform the more the number of g is reduced

[Gaston]

This is why in the event of an impact at 50 km / h against a (large) concrete wall, there is less danger in a sedan than in a Leclerc tank.

[chatelot16]

except that with a Leclerc tank the walls are never big enough and the tank passes through without slowing down much!

[Did67]

then the more scrap there is to deform the more the number of g is reduced

If I remember correctly, g is the deceleration; mathematically, it is the derivative of speed.

So in a car, we try to make the deceleration at the level of the human body as small as possible while knowing that we only have the length of the car in front of the driver to dissipate energy by programmed deformation of the bodywork.

Oo is caught between two extremes: a very thick "shell", so hard that the "infinite" deceleration transmitted by the wall is transmitted entirely to the body. Infinite deceleration for the body = death.

And at the other extreme, a body so deformable that it is the body that ends up against the obstacle ... Same result.

Between these two extremes, there is the programmed deformation, which plays more than the thickness of the sheet itself ... And which may be just enough to slow down the body without exploding the internal organs ...