Emergency Stop

[Horse]

If you never do it on public roads, you are missing a chance to calibrate your perception of how far it takes to stop on a public road. Having done both, I think the stopping distances look different on airfields and tracks.

I've made people walk the 60mph 'thinking' distance, "You've travelled this far at the same speed without even touching the brakes . . . " that's sobering enough for them

[Custom24]

that's sobering enough for them

It's not about sobering all of them. Some will be only doing 45 on a road I'd do 60 on, so it's a useful exercise for them to see that the stopping distance might not be as far away as they thought, or rather that they can drive faster if they look further ahead.

[Horse]

so it's a useful exercise for them to see that the stopping distance might not be as far away as they thought, or rather that they can drive faster if they look further ahead.

Quote from one of my trainees: "It's like having cataracts removed". I don't think she had, but the point's the same

[GJD]

I'd prefer not to do it on public roads

I just did it this morning with an associate. If you never do it on public roads, you are missing a chance to calibrate your perception of how far it takes to stop on a public road. Having done both, I think the stopping distances look different on airfields and tracks.

I certainly agree with you about calibrating yourself, but with your associate did you just practice an emergency stop, or did you go as far as parking up, putting the hazards on, getting out and pacing the distance (as per your previous post). I think I might be less comfortable doing all that on a public road.

[Kevin]

Although I did say I'd prefer not to do it on public roads, I have done pretty much exactly what Custom24 has suggested. I set the car up to do 60 (using a combination of cruise control and a satnav rather than relying on the speedo) and hit the brakes very hard (dry road and ABS, also clutch down) when reaching an identifiable point on the road. I quickly got out and marked the point where the car had stopped using one of those yellow tyre crayons, then parked up off the road. I even went to the extent of measuring the distance with a tape! A bit obsessive some might say. I wouldn't like to attempt the same experiment on the public road in the wet. I've done skid pan training in a truck, but that was on an airfield, which was just as well because when 7 tonnes starts to spin it's very difficult to bring it back into line in what would be the normal width of the average road. But again, Custom24 is correct, perception of distance is much different on an airfield.

[Russ_H]

Would a learner, when on test, be penalised for not leaving the clutch pedal alone until just before stopping, as recommended by the DSA or would it not matter?

When I was examining for DSA, I ignored the technique and judged on the results, on the basis that I simply
didn't know the recommended method for every car that might come my way.

I do not remember many candidates failing on the emergency stop. Bear in mind that there's only a one in three chance of being asked to carry out the exercise.

The most popular reasons for failing, as I remember them, were:

1) poor mirror use
2) excessive junction and roundabout approach speed
3) poor observation before emerging at junctions and roundabouts
4) failing to make reasonable progress
5) right turns at lights, especially at yellow box junctions
6) corner reverse and reverse parking

This is a general purpose list. Some test centres had particular types of hazard that used to cause considerable difficulties for candidates.

Regards,

Russ

[Custom24]

or did you go as far as parking up, putting the hazards on, getting out and pacing the distance (as per your previous post). I think I might be less comfortable doing all that on a public road.

Yes we did it all. You get less than half the benefit of the exercise if you don't walk back to the start of the braking, and then add on the thinking distance, then allow the associate to turn around and look at the car.

I don't actually pace the distance out as I wrote a little gps measuring program for my phone. But I don't see much danger in parking the car on a straight road with the hazards on, and then walking along said road. These are things people do all the time.

[Custom24]

I wouldn't like to attempt the same experiment on the public road in the wet.

Why not?

[Horse]

But I don't see much danger in parking the car on a straight road with the hazards on, and then walking along said road. These are things people do all the time.

I'd advise you to think agan about that one . . .

eg
http://www.informaworld.com/smpp/conten ... a713808723

Drivers who collide with a vehicle that is parked on the hard shoulder of a motorway or dual-carriageway sometimes claim not to have seen it before the collision. Previous research into vehicle conspicuity has taken such 'looked but failed to see' claims at face value, and concentrated on attempting to remedy the problem by making vehicles more conspicuous in sensory terms. However, the present study describes investigations into accidents of this kind which have involved stationary police cars, vehicles which are objectively highly conspicuous.

[Gareth]

Without having followed the link to check ... it's well known there is a tendency to steer towards where one is looking. This is often a problem for learners, and sometimes a problem for more experienced drivers when they become distracted from the task at hand.

[Horse]

Without having followed the link to check

That's why I posted an exerpt from the abstract . . .

it's well known there is a tendency to steer towards where one is looking.

Again:
Drivers who collide with a vehicle that is parked on the hard shoulder of a motorway or dual-carriageway sometimes claim not to have seen it before the collision. Previous research into vehicle conspicuity has taken such 'looked but failed to see' claims at face value, and concentrated on attempting to remedy the problem by making vehicles more conspicuous in sensory terms. However, the present study describes investigations into accidents of this kind which have involved stationary police cars, vehicles which are objectively highly conspicuous.

[fungus]

I did an experiment with a learner a few weeks ago.

Driving at 30mph on a quiet residential road that was straight with a kerb. The road surface was dry, and the cars tyres had a tread depth of about 7mm rear, and 5mm front. Using a lamp post as a marker, I gave the command STOP. Although the pupil knew that he was going to do an emergency stop at some point, he didn't know exactly when. At the point where we stopped, I made a note of roadside features. We then parked the car and measured how far it took him to come to a halt. Counting the kerb stones (17) at 3ft each, we could see that he had stopped in 51ft. As I said, I teach brake. then clutch a fraction of a second later.

As to whether an examiner would frown upon it if a candidate didn't brake as per the DSAs Driving the Essential Skills, I think Russ has just about summed it up. Most would be more concerned that the candidate stopped the car promptly, and under controll.

[Custom24]

I'd advise you to think agan about that one . . .

Drivers who collide with a vehicle that is parked on the hard shoulder of a motorway or dual-carriageway sometimes claim not to have seen it before the collision

Food for thought certainly, but I'm uncertain of the relative risk vs the reward of the exercise, which is not insignificant.

I've heard before that parking at an angle is what the police do nowadays to alert people to the fact that the vehicle is not moving. It's not an option for me.

I guess an alternative might be when we come to a stop for me to get out and remain at that spot, and instruct the driver to park in a pre-arranged safer place. They then return and stay at that spot. Then I can walk back to the braking point, add on the thinking distance and say "look how far away I am".

It's a good compromise, even if, as I suspect, the learning effect is not as pronounced because they are not looking at their car stopped in the road, but at a person.

If anyone thinks that it is the very act of walking on the road which is dangerous, then I think they should stay indoors.

[Gareth]

That's why I posted an exerpt from the abstract . . .

My point is that while the exact detail of why it happens may not be fully understood, it is well understood that drivers tend to steer towards where they are looking. When I say well understood I mean it has been known about since before you or I were born. While investigating it further may be of passing interest we (all) already know the tendency against which we must guard.

[Kevin]

I wouldn't like to attempt the same experiment on the public road in the wet.

Why not?

Perhaps I'm too risk averse. My reasoning for not wanting to attempt it on public roads in the wet is based on my experience of trying to handle a truck on a skid pan. In slippery conditions (and perhaps I should have said something more like ice rather than just wet), should the vehicle start to spin it might take longer to bring it back under control than there is room to do so, especially if the person performing the exercise doesn't have much experience of handling a vehicle in a skid. Invariably, where I live anyway, roads quiet enough to be able to practice this exercise tend to be quite narrow (compared to an A-class road) so there's little room for error, unlike on an airfield, for example. On reflection, I could start from slower speeds, rather than start at 60. I'll give it a go and see how I get on.

Would a learner, when on test, be penalised for not leaving the clutch pedal alone until just before stopping, as recommended by the DSA or would it not matter?

When I was examining for DSA, I ignored the technique and judged on the results, on the basis that I simply
didn't know the recommended method for every car that might come my way.

Russ

Thanks Russ. That seems a sensible and pragmatic approach to the use of the clutch during the emergency stop and answers my question.

Regards,

Kev