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Re: I'm resigned to driving slower and slower.

Posted: Fri Jul 15, 2016 8:13 am
by martine
sussex2 wrote:
martine wrote:
sussex2 wrote:At very least by making people have proper eye tests before being given a licence; to be repeated at regular intervals whilst they hold the licence.
I and a few of my veteran colleagues are firmly convinced that this single measure could help a lot.

Why?


If you mean my last sentence it is because we/I think that poor eyesight, and in particular tunnel vision, is widespread and often not diagnosed.

Do you have any evidence or just gut feel?

Re: I'm resigned to driving slower and slower.

Posted: Fri Jul 15, 2016 8:38 am
by sussex2
martine wrote:
sussex2 wrote:
martine wrote:
sussex2 wrote:At very least by making people have proper eye tests before being given a licence; to be repeated at regular intervals whilst they hold the licence.
I and a few of my veteran colleagues are firmly convinced that this single measure could help a lot.

Why?


If you mean my last sentence it is because we/I think that poor eyesight, and in particular tunnel vision, is widespread and often not diagnosed.

Do you have any evidence or just gut feel?


My own observations of peoples eyesight which in many cases is poor and rarely tested.
We did, many years, ago a completely unprofessional test of pupils at a driving school and found many of them had poor eyesight; legal (just) for the driving test but poor.

Re: I'm resigned to driving slower and slower.

Posted: Fri Jul 15, 2016 8:52 am
by Horse
The bike training centre I used to be involved with regularly had static displays in the town centre. One year we borrowed a Keystone (?) test machine. Through the day we test about 85 people, mostly drivers.

IIRC, 12 had eyesight problems which put them below the driving standard.

We also found out later that a child we tested, and suggested that the parents arranged further 'official' tests, had a previously undiagnosed serious eye problem.

Re: I'm resigned to driving slower and slower.

Posted: Fri Jul 15, 2016 8:59 am
by sussex2
In Spain anyone over 40 must have an eye test every five years and their licence is valid for the same amount of time.
Whether this effects or improves safety I have no idea but at least people are having some sort of test.

Re: I'm resigned to driving slower and slower.

Posted: Sat Jul 16, 2016 2:56 pm
by Astraist
Horse wrote:Things that can't be altered are the 'scientific' aspects: reaction time and minimum braking distance*. What can be influenced are the elements I've mentioned, and they're not unique to AD.

* And that could pretty much be achieved by anyone with ABS stamping on the pedal.


Both reaction time and braking distance can be changes with driver training. Reaction time is longer for the unexpected. An observant driver will enjoy shorter reaction times in those instances where he or she can anticipate the possible outcomes.

Braking distance for most drivers is largly elongated through hesitant braking (hence the need, largely, for Brake Assist), too much fiddling with the steering and sometimes by not using the clutch appropriately in doing so.

One can also describe to a driver the important contribution of good tyres and dampers to shorter stopping distances. Replacing them early with performance in mind rather than mere integrity helps enormously.

Re: I'm resigned to driving slower and slower.

Posted: Sun Jul 17, 2016 6:30 am
by sussex2
Astraist wrote:
Horse wrote:Things that can't be altered are the 'scientific' aspects: reaction time and minimum braking distance*. What can be influenced are the elements I've mentioned, and they're not unique to AD.

* And that could pretty much be achieved by anyone with ABS stamping on the pedal.


Both reaction time and braking distance can be changes with driver training. Reaction time is longer for the unexpected. An observant driver will enjoy shorter reaction times in those instances where he or she can anticipate the possible outcomes.

Braking distance for most drivers is largly elongated through hesitant braking (hence the need, largely, for Brake Assist), too much fiddling with the steering and sometimes by not using the clutch appropriately in doing so.

One can also describe to a driver the important contribution of good tyres and dampers to shorter stopping distances. Replacing them early with performance in mind rather than mere integrity helps enormously.


'sometimes by not using the clutch appropriately in doing so' - would you expand on that please.

Re: I'm resigned to driving slower and slower.

Posted: Sun Jul 17, 2016 7:11 am
by Astraist
In an ABS-equipped car, you want to declutch right after you initiate the braking. Otherwise, the engine, trying to resist the shutdown that the massive retardation is effectively forcing it to do, will apply a bit of driveline torque to the driven wheels and mess with the function of the system.

Is it a huge effect? No. But it does elongate the stopping distance. Trying to apply both simultaneously, on the other hand, can make it harder for drivers to apply the brakes as quickly as they otherwise could have.

Re: I'm resigned to driving slower and slower.

Posted: Sun Jul 17, 2016 8:40 am
by sussex2
Astraist wrote:In an ABS-equipped car, you want to declutch right after you initiate the braking. Otherwise, the engine, trying to resist the shutdown that the massive retardation is effectively forcing it to do, will apply a bit of driveline torque to the driven wheels and mess with the function of the system.

Is it a huge effect? No. But it does elongate the stopping distance. Trying to apply both simultaneously, on the other hand, can make it harder for drivers to apply the brakes as quickly as they otherwise could have.


Thank you and that is also how I understand it.

Re: I'm resigned to driving slower and slower.

Posted: Sun Jul 17, 2016 8:46 pm
by fungus
Astraist wrote:In an ABS-equipped car, you want to declutch right after you initiate the braking. Otherwise, the engine, trying to resist the shutdown that the massive retardation is effectively forcing it to do, will apply a bit of driveline torque to the driven wheels and mess with the function of the system.

Is it a huge effect? No. But it does elongate the stopping distance. Trying to apply both simultaneously, on the other hand, can make it harder for drivers to apply the brakes as quickly as they otherwise could have.


That is exactly how I teach my pupils to emergency stop. As Reg would say "Muller the brakes as hard as you can, clutch down." keep up the presure on the pedal.

Nigel.

Re: I'm resigned to driving slower and slower.

Posted: Sun Jul 17, 2016 10:13 pm
by martine
sussex2 wrote:My own observations of peoples eyesight which in many cases is poor and rarely tested.
We did, many years, ago a completely unprofessional test of pupils at a driving school and found many of them had poor eyesight; legal (just) for the driving test but poor.

OK but all I can say is, it's not my experience. I've not come across a leaner yet who falls below the legal minimum and I've only had one driver on the NDORS National Driver Alertness Course (I help with) who was marginal.

That's not to say it's not a problem (esp with older drivers) but personally I think there are other more effective things which could be done to better improve road safety.