Advanced driving

[ScoobyChris]

Why is braking and changing gear simultaneously frowned on, I don't understand the reasoning. Is there a reason, or is it one of those things that gets passed on and nobody asks why?

A few reasons I can think of are .... a) changing down a gear while braking will not be smooth (unless you can heel 'n' toe!), a hand is leaving the wheel during braking and c) it shows that you're rushing your approach to a hazard which shows poor planning/anticipation/awareness.

Here's how a traf pol explains full separation:

Firstly a lot of people convince themselves that they are performing full seperation' date=' when infact they actually perform partial overlaps. I'll explain....

[u'] Full seperation[/u]

What should be happening for full seperation, is that when you are on the brake your left foot should not be over the clutch. If your left foot goes to the clutch early you will depress it before it is time, you can't help it. If it's not there you can't depress it. If you visualise the three pedals, the time that your foot should go to the clutch is at the same time as your foot moves from brake pedal to the accelerator, so they move to the right in unison. If you are doing it correctly it will not feel at all natural to start with, it should feel really exaggerated, so you don't have the foot over the clutch until the other foot has left the brake.

The most common cause for people not being able to seperate is not making enough time to do it, and the cause of that is insufficient second stage braking. You can't brake to the hazard, you have to brake away from it. The system is a series of appointments & we all know that if you are late for your first appointment it has a knock on effect & you run out of time.

If we think of a typical tightish left turn from a major road into a minor road, you are only going to turn in at say 10mph. At 10mph we are travelling at 15ft per second. We need at least 2 seconds for our unhurried gear change in the system. That is 30ft for the gear change. What you effectively have to visualise is an artic parked between you & the junction right up to the mouth of it. You need to be at the right speed for the turn & off the brakes when you get to the rear of the artic. Then as you travel along the length of the artic you get your unhurried gear (with a good "Rev" as the gear lever passes neutral) & be off the clutch with the pedals blanced before entry. If you've got the timing exactly right, you should be off the clutch & just have time to raise your left hand to your mouth & blow on your fingernails before you take the wheel with your left hand at a 12 O'clock position & pull the steering to turn in.

When you are braking away from the junction to make room, think artic !

A common fault is people doing partial seperation (but believing they are actually seperating). You shouldn't be partial seperating, it's full seperation or overlap.

Partial seperation

If the foot goes to the clutch it will inevitably be depressed too early. Those who suffer from this do the following. As they release the brake pedal, because the foot is over the clutch they depress the clutch, in effect the feet just passing each other at the top end of pedal travel (just starting to presss one whilst just finishing with the other). This shouldn't happen. Anyone watching your feet should see clear seperation & both feet moving right at the sametime as described in full seperation.

Full overlap

A full overlap is perfectly acceptable on the grounds of safety. It shouldn't of course be a forced action as a result of a misjudgement, but should instead be part of a pre-planned approach to compromise the system on the grounds of safety. In commentary you would say "I am going to overlap on the grounds of safety because......" NOT " I overlapped because...." (which is historical & never convincing.)

For the full overlap you would extend the braking (so it's slightly less firm in the 2nd stage brakes) & as you are alongside the artic whilst still on the brake, you fully depress the clutch & take the required gear (there is no "Rev" on the downchange with an overlap. This is not a problem because road speed & engine speed will be so low & slightly slower than if you had seperated.) You should then start to gently release the clutch & effectively come off the clutch & brake pedal together at the correct speed just prior to turning in. You should still also be off the brake & clutch, with your foot on the accelerator, BEFORE you turn in.

The typical times that an overlap would be used as part of a pre-planned approach are.

1) Where you wish to turn left or right from a major road into a minor & it is on a steep downhill gradient. This is because where you unhurriedly take your gear over that 2 seconds, the vehicle will roll on a great deal, picking up speed & this will result on your entry speed being too high with you then ending up running wide into the new road & into conflict with others.

2) Where you overlap for one close behind so as to meet with their expectations of your braking. Most people turn left steering with one hand & catching a gear mid turn with the other. This is what they will expect you to do also. They expect you to brake all the way up to & into the turn. They will not expect you to brake firmly away from a junction at up to an artic distance away. So we overlap to meet with their expectations in order to not get an adverse reaction from them & so that they don't run into the back of us. We still should be off the brake & clutch before turning in though.

In general if you are considering an overlap, if there is a vehicle behind & it is going to have to brake for you taking the turn, then you can justify the overlap.

3) Where we want to take a junction left & there is a vehicle in our current road waiting to turn right across our path into that junction. Again we overlap to meet with their expectations of braking. If we brake away in these circumstances they may see this as an invitation to turn in ahead of us & pound to a penny they turn in as you come off the brake to get your gear resulting in a hurried re-application of the brakes to avoid a collision.

4) Where we want to take a junction right & there is a vehicle in that junction waiting to pull out & turn right across our path. This again is so that they don't see our braking as an invitation to pull out across our path causing potential danger.

We don't do an overlap where we want to turn right in order to complete the turn across the path of a quick one towards on the our road. This is because we would then be doing the overlap for speed (progress) NOT for safety. We instead would have to pull up & take 1st gear, wait for the vehicle to pass & then turn in when safe. We can compromise the system for safety as safety is the top priority, but we can't compromise the system for speed, which has a lower priority than the system itself.

Remember the order of priority is

Safety

System

Smoothness

Speed

You can compromise one "S" for an "S" above it in the list, but not for one below it.

The first thing you need to do is get used to braking without having your foot near the clutch & to do that try this exercise. Find some very quiet roads to practice on & make sure you check your mirrors & that it is clear behind before you do it. At a decent speed come off the drive & use a little acceleration sense before feeding in the gentle brakes & going smoothly to firmer brakes (& I mean firm). The attitude of the car needs to change so that the weight transfers forward. If your car is a petrol car & you are in 3rd you should be able to get comfortably down to about 10-12mph without it stalling. Make sure as you do it your foot is nowhere near the clutch. When you have finsihed the firm braking & got down to that speed, gently release the brake pedal (3rd stage braking, don't jump off it !) so that they weight transfers gently back & inertia lets the vehicle roll on.

Count to 2 then go to the clutch & take second gear. This is really exaggerating the seperation.

Accelerate back up to speed & repeat. Just get used to braking firmly away without your foot over the clutch so that you have the confidence to do it.

As it becomes easier to do, you can reduce the time you wait to take the gear.

The hand shouldn't leave the wheel to go to the gear lever unless the foot is going to the clutch & vice versa.

The only time other than a planned overlap, that the foot should go to the clutch whilst you are still on the brake, is when you think it may stall & you have to depress the clutch to prevent it. Anytime you do this you should be going to 1st gear OR it's an overlap & not on the grounds of safety either.

Chris

[superskib]

WOW!!!!!

Thanks Scooby Chris.

What a detailed answer - I'll print it out and digest it after an aspirin and a lie down in a darkened room.

Incidentally there are two 'a's in separation not two 'e's

Regards Gibbo

[superskib]

Second reply,

After reading the Policeman's response and thinking about it, I still don't think it gives reasons that are valid. It describes the process very thoroughly; but it is describing what it is, and how it is done, but not why. Indeed his reasons for overlaps are more reasonable inasmuch as it allows for other peoples expectations, and thus may avoid accidents.

His comments about preplanning are only really valid if one accepts that separation of the two processes is ABSOLUTELY essential. If that is so, why is it so?

Equally I don't find the comment about smoothness convincing. I can accept that smooth driving is a valid process, especially on slippery roads when jerky movements might cause a skid. But simultaneous braking and gear changing are not inherently unsmooth

[ScoobyChris]

Incidentally there are two 'a's in separation not two 'e's

Yup - but I quoted as he'd written it

Chris

[TaviaRS]

Second reply,

After reading the Policeman's response and thinking about it, I still don't think it gives reasons that are valid. It describes the process very thoroughly; but it is describing what it is, and how it is done, but not why. Indeed his reasons for overlaps are more reasonable inasmuch as it allows for other peoples expectations, and thus may avoid accidents.

His comments about preplanning are only really valid if one accepts that separation of the two processes is ABSOLUTELY essential. If that is so, why is it so?

Equally I don't find the comment about smoothness convincing. I can accept that smooth driving is a valid process, especially on slippery roads when jerky movements might cause a skid. But simultaneous braking and gear changing are not inherently unsmooth

[superskib]

Thanks Tavia and Scoobychris,

Your 4 stages of competence is well known in teaching circles. I am at the conscious incompetence stage at present and am trying to get to the conscious competence level ie I am trying to fully understand the reasons for everything I am being asked to do before I get to the final stage when I will be on 'automatic' ie not having to think about every action.

You are absolutely right when you say the observation/anticipation aspect is more important. I want to be able to concentrate on the unusual things, like the kid playing ball behind the parked car for instance.

My Observer for the IAM has promised me a demonstration drive in his Octavia TDI estate so I will be able to see it in action. He passed the Institute test in 1974 so he is very experienced, and a nice chap to boot.

I am also reminded of the saying "If it waddles like a duck, and quacks like a duck, it probably is a duck" This suggests to me that there is a reason for separation - I just want to know what it is.

PS I taught (past tense of teach) in FE, HE, and even some Primary children for a spell. My subject was lettering - handwriting, calligraphy, signwriting, lettercarving and electronic typography - all of which have nothing to do with driving I'm afraid!!!!

[TaviaRS]

PS I taught (past tense of teach)

Spot the after my comment

The primary reason for it was for stability, ie asking the car to do one thing at a time to maintain balance, rather like the steering whilst changing gear, braking whilst turning etc. A potential "hazard" of changing down whilst braking is that you get additional engine braking. Not always a bad thing but it can unbalance the car if you aren't that smooth with the downchange. The implication then was that if you did a BGOL you had not anticipated what you would have to be doing and it was seen as being in a rush rather than a considered option.

I see your point about new cars being different to old cars. When I first did my test way back, BGOL was an instant downgrade if not a fail. These days, as pointed out in the quote which Chris put up, you can gat away with it.