how effective is 'skid testing' by cops?

[marty]

i've seen bikers go over 100m after hitting something, but they are usually going a bit quicker, and they were all dead. had a head inside a helmet go 150m once. that took some finding too!

also had a kid asleep in the back of a car that hit a power pole down sh27 many years ago - he was ejected out of the car (through the back window) and found with a broken leg about 60m away.

i could see how the car would stop 70-80m away from the person they hit, but most pedestrians go over the bonnet, windscreen, and into the air, landing reasonably close to the point of impact. unless it was a Hummer that hit her...

[Lou Girardin]

If she was thrown 80 metres, she would've landed in pieces. Throwing a pedestrian that far is totally different from a body thrown from an already moving vehicle.
As for stopping distances, I have strong suspicions about the accuracy of testing. It may work for an average car on average tyres, but when you start considering sticky tyres and hi performance brakes (even ABS) it starts to seem less than accurate. After all, how many bike/car tests show differences of up to 7 metres stoping from 100 km/h? But we never did skid testing so I stand to be corrected.

[Drunken Monkey]

...After all, how many bike/car tests show differences of up to 7 metres stoping from 100 km/h? ...

some examples, FYI:
Tested with an electronic G-timer, braking from 60mph (97km/h) to 0mph (damn imperial devices. Assumes 3feet per metre (close enough, but not exact)
All vehicles tested with 1 driver and 1 passenger unless otherwise stated.

2004 2L Mazda 6, auto, ABS:
42.0m, 2.86s
42.3m, 2.95s
40.3m, 2.77s
variation over 3 tests over the same surface = 2.3m

2004 2.3L Mazda 6 auto, ABS:
41.6m, 2.78s
34.0m, 2.01s ! <= braking peaked at 1.09Gs
41.3m, 2.68s
variation over 3 tests over the same surface = 7.6m

2005 Holden SV6, auto, ABS:
41.6m, 2.88s
46.6m, 2.99s
variation over 2 tests over the same surface = 5.0m

2005 Mitsubishi Lancer, manual, NO ABS:
57.6m, 4.34s
57.0m, 3.83s
variation over 2 tests over the same surface = 0.6m
(In this test the driver simply 'put the foot in it', there was no serious attempt at seeing if this was the fastest way to stop the car)

Some others (best braking acheived over 2 - 3 runs):
2005 Suzuki Swift, auto, ABS: 38.6m, 2.68s
2005 Ford Courier, auto, (braking type not recorded), driver only: 48.0m, 3.46s
2005 Mercedes C180K, auto, ABS: 39.3m, 2.65s

We have lots more data, I can't be arsed typing any more out.

We haven't done any bikes yet, still working on a easily transportable power source (probably going to make a cigarette lighter + fuse that can connect directly to the bike's battery).

[bugjuice]

so is your point that they are accurate or inaccurate?

[Drunken Monkey]

so is your point that they are accurate or inaccurate?

No point, just displaying some of the raw data. You need to draw your own conclusions.

Although one item does re-inforcce Lou's comment, there was 1 vehicle that had over 7m variation in stopping distance. This was also the shortest braking distance vehicle we have tested = 34m from 60mph. How much distance do the LTNZ say to allow for? (Add approx 30m travelled for your '1 second reaction' time)

[Skyryder]

I would have thought that tyre pressure would have an 'impact' excuse the pun on skid distance. Surely softer pressure would enhance stoppage as against harder pressure. Is that factured into the equation??

Skyryder

[bikerboy]

Not sure it really matters what the speed was. Fact is the person was killed.

From the police perspective the driver had to be speeding, otherwise at 50kpm the driver would have been able to stop, correct. Speed kills.

From the driver's point of view, no matter what fine, sentence, etc. they get, they still must live with the fact that they caused someone's death. No matter how cynical one is, still a hard ask in my book.

From the family's point of view, a tragic loss.

Will any of that change with the speed, or is it explotation of a someone's death to peddle the status quo?

[bugjuice]

Not sure it really matters what the speed was. Fact is the person was killed.

From the police perspective the driver had to be speeding, otherwise at 50kpm the driver would have been able to stop, correct. Speed kills.

From the driver's point of view, no matter what fine, sentence, etc. they get, they still must live with the fact that they caused someone's death. No matter how cynical one is, still a hard ask in my book.

From the family's point of view, a tragic loss.

Will any of that change with the speed, or is it explotation of a someone's death to peddle the status quo?

no, not at all.. This isn't what I'm asking, and it is very unfortunate that someone has died.
This isn't the focus of this thread.

The point is aside from the fact that this was a tragic accident, how can the police put a figure on the speed of the car in question? The end result of the skid isn't the point, it could have been into another car, or a lampost etc. It is unfortunate that it ended with the death of someone, but it's not the question/discussion. Could the car have been going faster than what the police say? This would make him even worse off.. or was he telling the truth and the police car looks to be going faster.. that's the point I'm getting at. There is no question about his guilt, or even the remotest possibilty that he might be innocent. By no means. He's guilty.
This is just a hypothetical thread that was brought about by a tragic accident. We're not that shallow!

At times like this, everyones thoughts are with the family. without question.

[Lou Girardin]

Not sure it really matters what the speed was. Fact is the person was killed.

From the police perspective the driver had to be speeding, otherwise at 50kpm the driver would have been able to stop, correct. Speed kills.

From the driver's point of view, no matter what fine, sentence, etc. they get, they still must live with the fact that they caused someone's death. No matter how cynical one is, still a hard ask in my book.

From the family's point of view, a tragic loss.

Will any of that change with the speed, or is it explotation of a someone's death to peddle the status quo?

Come on now, you don't know the circumstances at all. Do you think that at 50 k's a car can stop instantly? Step out in front of a car doing 50 k's and if there isn't room for the car to stop you're toast. Most pedestrian fatalities are actually from drunks walking out in front of cars