Technical If safety is a concern...

[bredsticz]

Ahh! Your right there! TBH I just saw it as between 2 cars travelling 40MPH, the impact is 80MPH as thats the speed the gap between them is decreasing but to get that force one car would have to go from 40mph to -40MPH

 

[MikeSalt]

its all well and good a car having 5* but what happens if a big 5* car hits a small 5* car????

Ahh, excellent video Andy, and perfectly demonstrates the conservation of momentum at work (with the lighter 500 getting pushed backwards, despite same initial speed).

Of course, EuroNCAP would never publish official figures for car-on-car tests like this because the larger gas-guzzlers would come out on top with their 2000 kgs+ chassis.

 

[Andy Monty]

It's a funny concept this 'closing speed' malarky because many people do transform it into the frame of a car hitting a stationary object at twice the speed. However, to do so would result in violating conservation of energy. When two (equal mass) cars collide at 40 MPH, the damage caused is roughly equal to twice the kinetic energy of one car, which is 2 x (0.5*m*v^2). However, the dissipation of the energy is divided between the two cars, so the energy is actually identical to hitting a solid stationary object at 40 MPH (although the dynamics are less predictable).

When you hit a solid object at twice the speed, because it is a v-squared relationship, doubling the speed (to 80 MPH) increases the collision energy by a factor of four! And since you are the only car involved, your car takes all the energy.

So, in conclusion, you are going to be subject to four times more damage hitting something solid at 80 MPH, than hitting a car of equal mass head-on, both doing 40 MPH.

Of course, if the car you hit is much heavier than yours, due to conservation of momentum, your car will absorb the largest proportion of the energy. This is because you don't just decelerate from 40 to 0 MPH, but you actually get pushed backwards, effectively increasing the deceleration range (e.g 40 to -10 MPH).

then you learn the euro n-cap uses a deformable "block" just to give you another maths problem


And that manufacturers know safety sells so make their cars to "pass" the test which could make them worse in other types of crash





that and none of the cars tested are braking hard thus lowering the front end taking the front chassis rails and impact rail "off level"

 

[m20b25]

I was the passenger in a mk 1 sporting when it rolled doing a very illegal speed. It all happened so fast, the car became airborne and began to roll, not a very nice experience. We landed in someones front lawn on all fours. Both me and the driver walked away, unscratched.
My dad, on his way to work in his mk 1 punto, got rammed under a truck by an idiot in a passat doing over 80 mph, completely ruining both cars. Even the truck driver thought another truck had hit him the impact was so violent. My dad walked out of the car, in a very very foul mood and a sprained arm but otherwise unharmed.
2 examples proving these are a tough little car

 

[PuntoSS]

But Mike, another thing you have to remember is that this is not just MK1 Punto's that have low ratings. Remember they were built in the 90s, before the Euro NCAP tests were introduced; manufacturers were working to little/if any safety specifications and standards at all.
If you look at some of the videos of the older cars like Vauxhalls on the NCAP site, I'm sure you'll find they weren't far off!

Car safety has improved since the NCAP tests were introduced and hence the MK2 and Grande Punto's have better ratings, although the more airbags and safety features you can opt to have on purchase, the more expensive the vehicle.

Thus, these NCAP tests are probably being based on the bog standard models and not the top of the range models. So if you buy a higher spec model, then the safety rating would theoretically be better, I'd assume.

 

[MikeSalt]

I was the passenger in a mk 1 sporting when it rolled doing a very illegal speed. It all happened so fast, the car became airborne and began to roll, not a very nice experience. We landed in someones front lawn on all fours. Both me and the driver walked away, unscratched.
My dad, on his way to work in his mk 1 punto, got rammed under a truck by an idiot in a passat doing over 80 mph, completely ruining both cars. Even the truck driver thought another truck had hit him the impact was so violent. My dad walked out of the car, in a very very foul mood and a sprained arm but otherwise unharmed.
2 examples proving these are a tough little car

Perhaps then , in 'real world' crashes, the mk1 isn't so bad. To be honest, how many people do you hear getting killed in a mk1 Punto? It's always old Fiestas, KAs and Saxos.

 

[karbineftw]

I was the passenger in a mk 1 sporting when it rolled doing a very illegal speed. It all happened so fast, the car became airborne and began to roll, not a very nice experience. We landed in someones front lawn on all fours. Both me and the driver walked away, unscratched.
My dad, on his way to work in his mk 1 punto, got rammed under a truck by an idiot in a passat doing over 80 mph, completely ruining both cars. Even the truck driver thought another truck had hit him the impact was so violent. My dad walked out of the car, in a very very foul mood and a sprained arm but otherwise unharmed.
2 examples proving these are a tough little car

Glad that everyone was ok! How illegal are we talking though like?

 

[MikeSalt]

Glad that everyone was ok! How illegal are we talking though like?

Too illegal to publish I would guess. Andy, I missed that point about hard braking the first time I read your post, this is indeed interesting. They should really modify the test so that the car approaches the block at 50 MPH, but at 10m away, the car's brakes are applied with fixed mechanical pressure. This test is not only more realistic due to brake dive, but it actually gives better-braking cars a higher score, since they hit the object more slowly.

 

[bredsticz]

Too illegal to publish I would guess. Andy, I missed that point about hard braking the first time I read your post, this is indeed interesting. They should really modify the test so that the car approaches the block at 50 MPH, but at 10m away, the car's brakes are applied with fixed mechanical pressure. This test is not only more realistic due to brake dive, but it actually gives better-braking cars a higher score, since they hit the object more slowly.

And if you crashed due to brakes failing? Or fall asleep at the wheel?
It's showing worst case senario at that speed

 

[DaveMcT]

If you really want to learn how to drive, do the training and get a bike licence and use the bike regularly. On a bike its life & death so after that you will see so much more when you drive a car.

As for ABS and TCS, I like them but I never drive like my life depends on them. The one occasion I needed the ABS (in a Ford Galaxy) the system paid for itself by saving me rear ending someone on the M5.

The TCS on the Punto HGT has recently got me up some icy hills so I'm a convert. It wont allow mad starts without wheel-spin so wont encourage queue jumping nutters at traffic islands.

 

[Andy Monty]

Andy, I missed that point about hard braking the first time I read your post, this is indeed interesting. They should really modify the test so that the car approaches the block at 50 MPH, but at 10m away, the car's brakes are applied with fixed mechanical pressure. This test is not only more realistic due to brake dive, but it actually gives better-braking cars a higher score, since they hit the object more slowly.

this is what got me thinking.... 2" different bet with the brakes applied and front suspension compressed your looking at a lot more

 

[m20b25]

Glad that everyone was ok! How illegal are we talking though like?

Lets just sasy the needle was very far in the right hand side!!!

 

[Noddy]

this is what got me thinking.... 2" different bet with the brakes applied and front suspension compressed your looking at a lot more

YouTube- Fifth Gear - height crash test

Thats made my mind up about getting that set of lowering springs

 

[Most Easterly Pandas]

Also the mk2 is better than the mk1 I agree but theres still alot of damage,

You can't judge an accident siverity by the amount of damage

Infact often the car with the most exterior deformation was the better car to be in as the deformation abzorbed alot more of the impact rather than it being the passengers that do so.

It's a funny concept this 'closing speed' malarky because many people do transform it into the frame of a car hitting a stationary object at twice the speed. However, to do so would result in violating conservation of energy. When two (equal mass) cars collide at 40 MPH, the damage caused is roughly equal to twice the kinetic energy of one car, which is 2 x (0.5*m*v^2). However, the dissipation of the energy is divided between the two cars, so the energy is actually identical to hitting a solid stationary object at 40 MPH (although the dynamics are less predictable).

I switched off with the maths

I do know that he 40MPH EuroNCAP (bearing in mind that there are several different NCAP's that have different testing methods) into an ofset deformable barrier is the equivilent of two identicle cars hitting head-on at 35mph.

Thats made my mind up about getting that set of lowering springs

Thats one way of looking at it.