A car with locked-skidding front wheels will stop better than one with ABS as ABS takes longer to stop!

Did he specify on snow or gravel (in which case it would be true).

2 car travelling at 50mph having a head on is a 100mph collison………..OFFS.

IME, Even after to explain it to people slowly, only about 2% of the population will understand that. 🙄

some gems
a blue round sign means cyclists MUST (shouted) use the cycle lane.

Ooooh I think I’d have been having words with him or his supervisor about that one!

Can someone explain the 50mph one? Why is that not right? 😳
(it’s late and I’m too hot so apologies if it is obvious)

I did one a little while back. Found it pretty good actually.
Proved to me what lack of hazard perception and road knowledge inc road signs+speed limits the majority of vehicle drivers have.

I’ve always thought a 5 year top up test would be worthwhile consideration for drivers+riders. Simple and cheap, but it will keep us all upto a certain level of competency.

“TuckerUK – Member
A car with locked-skidding front wheels will stop better than one with ABS as ABS takes longer to stop!
Did he specify on snow or gravel (in which case it would be true). “

No they showed the old-ish road safety add why the nissan locks up and knocks a little lad down, so dry tarmac.

As for Newtons third law….. if you tell me something i know is a untrue, then how i am going to trust your other facts.

I’ve always thought a 5 year top up test would be worthwhile consideration for drivers+riders. Simple and cheap, but it will keep us all upto a certain level of competency.

Yep, me too. 😳

🙂

Can someone explain the 50mph one? Why is that not right?
(it’s late and I’m too hot so apologies if it is obvious)

Closing speed is 100mph, but you would still only be decelerating from 50mph.

I’ve always thought a 5 year top up test would be worthwhile consideration for drivers+riders.

+1

In any other walk of life if you were put in charge of a piece of machinery that killed or seriously injured 25,000 people a year then you’d need to be re-tested every year.

Graham 2 cars each at 50mh =100mph divided by 2 cars =50mph each.
google mythbusters 2 cars they do a very visual demo of this,

Oh and one more thing they asked not 1 or 2 but 3 people to leave who hadn’t bought their driving licenses……so thats £80 for the course £65 fine and 3 points……darwin at work

Closing speed is 100mph, but you would still only be decelerating from 50mph.

Ahh – so you’d be thrown forward with (roughly) the same force as 50mph into a brick wall, I see.

Presumably it is still worse though, as you’ll have bits of the other car coming through your windscreen at 50mph and your crumple zones would be subject to far greater forces as they’d be getting hit from “both sides” (being squashed by your vehicle’s momentum while also being squashed by the oncoming vehicle).

Aye. You might also get run over, pushed back, spiked, spun, rolled or indeed a combo of all of then depending on what vehicle you collide with.

depending on what the vehicle you collide with.

Yeah, seems to me it would only really balance out if the vehicles are exactly the same mass and the crumple zones are symmetrical.

Many years ago a uni mate of mine was killed in a head on with a snow plough. Wasn’t a lot left of his car 😕

sugdenr
…I would happily go back again…

Surely that would that say something about the (in)effectiveness of the course…? 😉

Presumably it is still worse though, as you’ll have bits of the other car coming through your windscreen at 50mph and your crumple zones would be subject to far greater forces as they’d be getting hit from “both sides” (being squashed by your vehicle’s momentum while also being squashed by the oncoming vehicle).

Not really. Imagine the crumple zone absorbs energy in proportion to the deformation 1cm of deformation = 1kJ of energy (made up figures, but right ballpark)

If 1 car (500kg) hits a completley imovable brick wall at 50mph (22 m/s), the energy transfered is 1/2* mass * velocity suared = 0.5*500*22*22= 121kJ = 121cm of deformation (so the whole bonnet area).

If 2 cars hit each other at 50mph each thats then that twice (242kJ) the energy and twice the derformation, but that’s over 2 bonnets, so actualy it’s the same.

If 1 car is replaced by a truck weighing an infiite ammount then the change in velocity is negligable (i.e the truck just keeps going), then the change in speed is 100mph, but it’s not 1/2* mass * change in velocity squared, it’s just velocity. So in that case the energy transfered is doubled as the car decelerates to zero, then is re accelerated to 50mph backwards, 2.42m of car is crushed and the ocupant is very very dead.

What’ll really mess with your head is the earth is spinning at ~1200miles an hour, and moving round the sun as millions of miles an hour, so relatively, both objects have experienced a very small change in velocity! What I don’t quite understand is in that case going from 1250mph to 1200mph should have a different result than 1150mpg to 1200mph, i.e. driving east a crash should hurt a lot more than driving west.

[edit] that now reads a bit insensative after the snowplough

As for Newtons third law….. if you tell me something i know is a untrue, then how i am going to trust your other facts.

So basically, they were trying to convince you but you had an equal and opposite reaction to the advice?

As for Newtons third law….. if you tell me something i know is a untrue, then how i am going to trust your other facts.

I was agreeing with you!

Yeah, seems to me it would only really balance out if the vehicles are exactly the same mass and the crumple zones are symmetrical.

True. A tank doing 50mph crashing into a small car doing 50mph, the tank would feel a 0mph impact, the car 100mph…probably.