roadcraft site

"Zebee Johnstone" wrote in message
...
> In aus.motorcycles on Tue, 19 Feb 2008 08:48:21 +1100
> John Dwyer wrote:
>>
>> What is the likelihood of this situation changing? Low with present
>> policies. Riders/drivers who were originally licenced more than 20 years
>> ago
>> were probably not formally taught to ride or drive. They have no concept
>> of
>
> Funny how "20 years ago" is code for "a very long time" isn't it.
>
> I got my car licence in 1980. THere was a flourishing driving school
> industry even in backwards Perth. I failed the first driving test, my
> instructor said it was fairly common to do so and he wasn't the kind
> to lie to make someone feel better.
>
> The problem isn't that people aren't taught things, or even that they
> don't get tested.
>
> The problem is that crashes are rare.
>
> So that most people learn by experience that they don't need to keep
> big buffer zones, especially as if they do they are disadvantaged.
>
> Percentages hide so much. How many of these rear enders are at slow
> speed? How many are injury crashes? What was the actual cause, what
> made the rear-ender happen?
>
> Zebee

Zebee and others,

I draw my conclusions from my observations of gaps between vehicles on the
road, and from calculations on reaction times and required braking
distances. Most of the time you will not experience problems with smaller
buffer zones as the vehicle ahead of you will take some distance to stop.
But if it does not, you will become part of whatever has happened ahead of
you. The site http://www.datacraftsystems.co.uk/techniques/index.html
refers to a two second gap, which could result in a crash at as low as 30
km/h. Even low speed, non injury crashes can involve time and money in
having repairs done, preparing report for the police, and so on.

Like many things, buffer spaces are the responsibility of the driver or
rider. New riders need information that is soundly based.

John Dwyer
 >> Stay informed about: roadcraft site 

On 19/02/2008 1:21 PM, John Dwyer wrote:
> "Zebee Johnstone" wrote in message
> ...
>> In aus.motorcycles on Tue, 19 Feb 2008 08:48:21 +1100
>> John Dwyer wrote:
>>> What is the likelihood of this situation changing? Low with present
>>> policies. Riders/drivers who were originally licenced more than 20 years
>>> ago
>>> were probably not formally taught to ride or drive. They have no concept
>>> of
>> Funny how "20 years ago" is code for "a very long time" isn't it.
>>
>> I got my car licence in 1980. THere was a flourishing driving school
>> industry even in backwards Perth. I failed the first driving test, my
>> instructor said it was fairly common to do so and he wasn't the kind
>> to lie to make someone feel better.
>>
>> The problem isn't that people aren't taught things, or even that they
>> don't get tested.
>>
>> The problem is that crashes are rare.
>>
>> So that most people learn by experience that they don't need to keep
>> big buffer zones, especially as if they do they are disadvantaged.
>>
>> Percentages hide so much. How many of these rear enders are at slow
>> speed? How many are injury crashes? What was the actual cause, what
>> made the rear-ender happen?
>>
>> Zebee
>
> Zebee and others,
>
> I draw my conclusions from my observations of gaps between vehicles on the
> road, and from calculations on reaction times and required braking
> distances. Most of the time you will not experience problems with smaller
> buffer zones as the vehicle ahead of you will take some distance to stop.
> But if it does not, you will become part of whatever has happened ahead of
> you. The site http://www.datacraftsystems.co.uk/techniques/index.html
> refers to a two second gap, which could result in a crash at as low as 30
> km/h. Even low speed, non injury crashes can involve time and money in
> having repairs done, preparing report for the police, and so on.
>
> Like many things, buffer spaces are the responsibility of the driver or
> rider. New riders need information that is soundly based.
>

Absolutely agree with your last point. But what has this got to do with
your quote of:

> Riders/drivers who were originally licenced more than 20 years ago
> were probably not formally taught to ride or drive. They have no concept of
> the components that make up the required space that is required between a
> given vehicle and the one ahead. This situation is compounded by re-issue
> of licences, normally every five years, requires assessment of neither road
> rule knowledge nor driving skill.

Or am I just entering senility and missing the point? Or do you work for
a branch of government?

N/
 >> Stay informed about: roadcraft site 

John Dwyer wrote:

> Riders/drivers who were originally licenced more than 20 years ago
> were probably not formally taught to ride or drive. They have no concept of
> the components that make up the required space that is required between a
> given vehicle and the one ahead.

LOL. Normally we leave the outrageous generalisations and gross
misrepresentations of the truth here to Atec and Biggus but welcome
aboard anyway.

Nev..
'07 XB12X
 >> Stay informed about: roadcraft site 

"Yeebers" wrote in message

> By definition the only component of "space" is exactly that - space.
> Generally it's only referred to as such when empty.
>
> So if you want to get pedantic on our asses, start mentioning the "size"
> of the space. Otherwise your average tailgating P plater can say they
> leave "space" even if it is only 100cm of it.

Yeebers,

The following if from one of my much earlier responses to this topic and I
hope answers your question.

I have reservations about the reference to the Two Second Rule on this site.
I completed the NSW Pre-Learner's Course some time ago. They stated that
Crash Avoidance Space consisted of Reaction Time and Braking Time. They
stated that reaction time was an average of 1.5 seconds. Leaving a two
second gap allows only a 0.5 second gap in which to give yourself the space
to stop (my interpretation). You travel at 27.8 m/s at 100 km/h. A 0.5
second gap means that you have allowed only 13.9 metres to stop at 100 km/h.
May the Force be with you.

A gap of 4 seconds at 100 km/h is more realistic in my opinion. A three
second gap means that you will have to stop from 100 km/h in 42 metres.
This is a 0.94g stop. Allow a 3 second gap if you can reliably do 0.94g
stops, otherwise allow a 4 second gap at 100 km/h.

48% of all collisions in the ACT are rear enders. What any rider does is up
to him or her.

>
> John Dwyer wrote:
>> "bill_h" wrote in message
>>
>
>> ...They have no concept of the components that make up the required space
>> that is required between a given vehicle and the one ahead.
 >> Stay informed about: roadcraft site 

John Dwyer wrote:

> I have reservations about the reference to the Two Second Rule on this site.
> I completed the NSW Pre-Learner's Course some time ago. They stated that
> Crash Avoidance Space consisted of Reaction Time and Braking Time. They
> stated that reaction time was an average of 1.5 seconds. Leaving a two
> second gap allows only a 0.5 second gap in which to give yourself the space
> to stop (my interpretation). You travel at 27.8 m/s at 100 km/h. A 0.5
> second gap means that you have allowed only 13.9 metres to stop at 100 km/h.
> May the Force be with you.

I have reservations about the reference to the 1.5 second reaction time.
I reckon the average person could react to something occurring in
front of them in much, much less than 1.5 seconds. Hell, I reckon a
person doing a headcheck could react to something which occurred in
front of them, while they were facing the wrong direction in less than
1.5 seconds.
The other day on the cricket Ch9 replayed a catch in slow motion. The
ball took 0.76 seconds from the bat to Symonds hand, which he caught at
full stretch to his left with his hand merely cms above the ground. He
might look like a monkey but his arms aren't that long.

Nev..
'07 XB12X
 >> Stay informed about: roadcraft site 

On Feb 25, 4:59 pm, "John Dwyer" wrote:
> "Yeebers" wrote in message
>
>
>
> > By definition the only component of "space" is exactly that - space.
> > Generally it's only referred to as such when empty.
>
> > So if you want to get pedantic on our asses, start mentioning the "size"
> > of the space. Otherwise your average tailgating P plater can say they
> > leave "space" even if it is only 100cm of it.
>
> Yeebers,
>
> The following if from one of my much earlier responses to this topic and I
> hope answers your question.
>
> I have reservations about the reference to the Two Second Rule on this site.
> I completed the NSW Pre-Learner's Course some time ago. They stated that
> Crash Avoidance Space consisted of Reaction Time and Braking Time. They
> stated that reaction time was an average of 1.5 seconds. Leaving a two
> second gap allows only a 0.5 second gap in which to give yourself the space
> to stop (my interpretation). You travel at 27.8 m/s at 100 km/h. A 0.5
> second gap means that you have allowed only 13.9 metres to stop at 100 km/h.
> May the Force be with you.
>
> A gap of 4 seconds at 100 km/h is more realistic in my opinion. A three
> second gap means that you will have to stop from 100 km/h in 42 metres.
> This is a 0.94g stop. Allow a 3 second gap if you can reliably do 0.94g
> stops, otherwise allow a 4 second gap at 100 km/h.
>
> 48% of all collisions in the ACT are rear enders. What any rider does is up
> to him or her.
>
>
>
> > John Dwyer wrote:
> >> "bill_h" wrote in message
> >>
>
> >> ...They have no concept of the components that make up the required space
> >> that is required between a given vehicle and the one ahead.

A few days ago the owner of Balls Engineering(?) in Melb was killed
after he fell off his bike.

Its said that the fall may not have killed him, but the guy behind was
too close, had nowhere to go, and ran over his neck!

There are other things to worry about than just stopping, there is
also avoidance of obstacles. 42 metres sounds enough for me to be able
to take evasive action.

SteveB
 >> Stay informed about: roadcraft site 

Nev.. wrote:

> I have reservations about the reference to the 1.5 second reaction time.
> I reckon the average person could react to something occurring in front
> of them in much, much less than 1.5 seconds.

In drag racing, a 0.4 second reaction time is considered perfect.

First time I took the Pig for a run a got a 0.411 reaction time. Was
pipped for the prize for the best reaction time of the meet by some
arseclown who got 0.409. Beaten by two-thousandths of a second...

--
Toosmoky
Work to ride, Ride to Work...
http://users.tpg.com.au/smokey61
 >> Stay informed about: roadcraft site 

On Tue, 26 Feb 2008 06:34:35 +1000, Toosmoky
wrote:

>Nev.. wrote:
>
>> I have reservations about the reference to the 1.5 second reaction time.
>> I reckon the average person could react to something occurring in front
>> of them in much, much less than 1.5 seconds.
>
>In drag racing, a 0.4 second reaction time is considered perfect.
>
>First time I took the Pig for a run a got a 0.411 reaction time. Was
>pipped for the prize for the best reaction time of the meet by some
>arseclown who got 0.409. Beaten by two-thousandths of a second...

Yeah, but that is when you are anticipating something happening. When
you aren't expecting anything, about 1.5 would be a closer bet.
 >> Stay informed about: roadcraft site 

Kevin Gleeson wrote:
> Toosmoky wrote:
>> Nev.. wrote:

>>> I have reservations about the reference to the 1.5 second reaction
>>> time. I reckon the average person could react to something
>>> occurring in front of them in much, much less than 1.5 seconds.

>> In drag racing, a 0.4 second reaction time is considered perfect.
>>
>> First time I took the Pig for a run a got a 0.411 reaction time. Was
>> pipped for the prize for the best reaction time of the meet by some
>> arseclown who got 0.409. Beaten by two-thousandths of a second...

> Yeah, but that is when you are anticipating something happening. When
> you aren't expecting anything, about 1.5 would be a closer bet.

I doubt I'd react even that fast on the Nullarbor if an emu suddenly
appeared in front of me.

Theo
 >> Stay informed about: roadcraft site 

Kevin Gleeson wrote:

> Yeah, but that is when you are anticipating something happening. When
> you aren't expecting anything, about 1.5 would be a closer bet.

Nobody expects the Spanish Inquisition!...

--
Toosmoky
Work to ride, Ride to Work...
http://users.tpg.com.au/smokey61
 >> Stay informed about: roadcraft site 

Theo Bekkers wrote:
>
> I doubt I'd react even that fast on the Nullarbor if an emu suddenly
> appeared in front of me.
>
> Theo
>
>

Really?

And with all that practice too....


G-S
 >> Stay informed about: roadcraft site 

G-S wrote:
> Theo Bekkers wrote:
>>
>> I doubt I'd react even that fast on the Nullarbor if an emu suddenly
>> appeared in front of me.

> Really?
>
> And with all that practice too....

Seriously though, in the cut and thrust of city traffic, with lane-splitting
etc, you might achieve a reaction time of between .5 and 1 second. After
riding for six or more hours with no traffic going your way and a vehicle
coming the other way every 20 minutes or so, your reaction time to an
unexpectant event, (emu travelling at 40+kms/h crossing the road at right
angles), is going to be slower than that.

Theo
 >> Stay informed about: roadcraft site 

Theo Bekkers wrote:
> Kevin Gleeson wrote:
>> Toosmoky wrote:
>>> Nev.. wrote:
>
>>>> I have reservations about the reference to the 1.5 second reaction
>>>> time. I reckon the average person could react to something
>>>> occurring in front of them in much, much less than 1.5 seconds.
>
>>> In drag racing, a 0.4 second reaction time is considered perfect.
>>>
>>> First time I took the Pig for a run a got a 0.411 reaction time. Was
>>> pipped for the prize for the best reaction time of the meet by some
>>> arseclown who got 0.409. Beaten by two-thousandths of a second...
>
>> Yeah, but that is when you are anticipating something happening. When
>> you aren't expecting anything, about 1.5 would be a closer bet.
>
> I doubt I'd react even that fast on the Nullarbor if an emu suddenly
> appeared in front of me.

That's a pretty exceptional circumstance involving something completely
unexpected and unpredictable. The original discussion was about
reaction time to something happening in front of you, which you are
generally watching, and probably concentrating on.. ii.e. following
another vehicle at a particular distance.

Nev..
'07 XB12X
 >> Stay informed about: roadcraft site