Can someone remind me of the speed you need to achieve before perfoming the emergency stop when on test? I thought it was 30mph, and that you have to stop within the length of the vehicle you are driving?
I am pretty sure that it is 20mph that you have to acheive on the controlled stop rather than 30, and then stop within the length of the vehicle… …
G
i remember it being 20 mph , [zb] it i had 60 foot of drawbar behind me.
jon
Thank you. It must have been 30kph(roughly 20mph) I was thinking of.
See now, I’m certain for mine it was 25mph and stop within 2 vehicle lengths…but it was back a bit now, so I may well be wrong… 
It’s approximately 20 mph, not exactly. Also it’s called a braking exercise not an emergency stop (there is a difference but I can’t remember what it is )
WHEN I TOOK MINE IT WAS 25MPH
DSA book Official Guide to Driving Goods Vehicles states, “You should build up speed to about 20 mph.”
mrpj:
It’s approximately 20 mph, not exactly. Also it’s called a braking exercise not an emergency stop (there is a difference but I can’t remember what it is
The difference between an Emergency stop and a braking exercise, is during the braking exercise it would considered bad form to brake so hard that the examiner ends up doing a Garfield impression on the windscreen. 
You have to bring the vehicle to a controlled stop with in the coned area from a speed or aprox 20mph.
It’s really just a test to see that you can stop the thing before they take you out on the road.
they’re not too fussed if you’ve past the cone a bit by the time you’ve stopped, unless it’s halfway down the trailer or somthing.
I took my test last week in class one, unfortunately I did’nt pass owing to the reverse, but the controlled stop is carried out at a speed of approximately 20mph. It is not an ermerncy stop and the examiner does not want to be propelled forward. My instructer told me that it is about the same as approaching some traffic lights that change suddenly. That is the amount of braking they expect and it should be within the length of the vehicle. Thats what I did on both my class two and class one and the examiner was ok with it.
Hope this is of help.
In the dim dark past I seem to recall that 20mph was the going rate.
20 mph, about 30 kmh and then stop the vehicle within the length of the combination. When training on wagon & drag almost all students manage to stop within the length of the prime mover - try doing that in an artic!!
The ‘Controlled Stop Excersise’ is done at 20 MPH (not approx - some examiners are stickler for a dead on 20)
The run between cones is 61 metres and you have to START the braking excersise when the front of the vehicle is in line with the second cones, bringing the vehicle to a halt ‘in the shortest possible time, safely and under control’.
In other wordsthey dont want to see you locking the brakes, skidding the vehicle, nosediving the examiner onto the screen etc.
The reason it is done within the confines of the test centre is that the examiner wants to be sure he is not sitting next to some idiot who cant work air brakes properly and endanger both the himself (examiner) and other road users if he takes the driver out on the main public highway.
So rev it up at the start - hit 20 then cruise.
Apply brakes firmly - dont pounce on 'em - and stop nicely making sure the vehicle is at a dead stop before applying the handbrake.
No probs - easy.
The ‘Controlled Stop Excersise’ is done at 20 MPH (not approx - some examiners are stickler for a dead on 20)
Just read the DSA’sLGV book, and it says;
“you should build up a speed of about 20mph”[
However is also says in ‘faults to avoid’
driving too slowly, ie less than 20mph
So i’d still say ‘aprox’ 20mph, i mean if he failed you for doing 19mph you could quote the book at him/her and have the descision over turned. You could also point out that s/he’s looking at the speed from and angle so couldn’t possibly read it with that degree of acuracy. Certainly i’d say if you got too near 15, you’d fail though. There are of course one or two scumbags, but most are quite reasonable people.
Also in the Minimum test vehicle requirements it doesnt say anything about acceleration, so if you had a vehicle that wasnt capable of reaching 20mph in 61ft he/she couldnt fail you for that either. It would have to be pretty gutless not to be able to do it though!
If I remember correctly, however, Mothertrucker is a working HGV Driving Instructor and therefore knows what the real-life examiners are looking for…hence the comment about “some of them are sticklers”. 
MT, please correct me if I’m wrong.
Slightly off topic, but when I took my car test many years ago the “apprentice”
examiner sat in the front and his boss sat in the back doing his paperwork. When it came to the emergency stop the fellow in the back was so engrossed in his paper work he didn’t notice.
Well not until I hit the brakes, his nose hit the top of the front bench seat, his glasses landed on the floor and his paperwork landed every where. Didn’t know if to laugh or cry. Either way i failed.
Yes Lucy you are right.
I am a working HGV instructor and have been for nearly 20 years. The rules are supposed to be pretty much the same as when I started 20 years ago but there are subtle differences. Mainly it is that you HAVE to drive by the book. The book being the letter of the law of the highway code.
For example - years ago they never failed any driver for avoiding a marked bus lane out of its hours of use.
Now it is an instant fail. ie. If the sign says ‘Bus Lane between the hours of 8 and 10 am’ and you are on test at 10-30 and avoid that bus lane you are failed.
Reason given is that the highway codes states ‘always drive to the nearest AVAILABLE left hand lane at all times’.
If the bus lane is not in its hours of use then it is AVAILABLE so to avoid it is a fail.
I know I have digressed off the braking excersise thread but just giving an example of the black and white rules now in place at the DSA test centres.
And yes, some examiners are more sticklers for the rules than others.
But 20MPH it is so make sure you are on 20 and you dont give them any margin for doubt.
20 miles an hour approximate, if you do it at 22 thats fine if you do it at 18 thats fine.
25 and youll brake to harsh making it hard work, at 16 they will more than likely take you round to do it again.
it is an approximate spead of 20 in th ebook it say should…should not must!!
there is tolerance on each side as margin of error.
that is at all test stations across the uk.
it would not ussually result in a fail unless 1, u put examiner into screen.2 you repeatedly do it to slow. 3, as the back up plan incase of dispute.
"This is a test of your ability to stop the vehicle as quickly and safely as possible.
Look ahead and you will see 2 cones. When you’re ready, drive forward and try to reach a speed of 20mph.
As the front of the vehicle passes between the 2 cones, stop as quickly and safely as possible.
Do you understand the exercise?
Start when you’re ready please."
That being the exact DSA wording, i’d be tempted to think that;
a) You only have to try to reach a speed of 20mph; i’m sure 18 or maybe even only 17mph may be sufficient.
b) ‘As quickly and safely as possible’ doesn’t say anything about within the length of the vehicle etc, so on a wet day for example a stopping distance longer than the length of the vehicle (but still within the manoeuvreing area) will be acceptable. Skidding may well be deemed as not as safe as possible.
Remember that the examiner can ask you to go around again to attempt the Braking Exercise (it’s not an Emergency Stop) if you don’t get to (or near enough) 20mph.
With a bit of searching I also found the quote below which comes from the Examiners Guide to Marking I think.
In assessing the ability of the candidate, the Examiner must take into consideration the surface conditions and the weight of the vehicle. With an empty vehicle, some or all wheels may lock if excesive brake pedal pressure is applied. In the case articulated vehicles or vehicles towing trailers, this may result in jack-knifing and the Examiner should look for correct application of the brakes and correct handling of the steering.
I see it didn’t state that locking the wheels, i.e. skidding, is a serious driving fault (fail). So maybe there is an element of flexibility allowed on the part of the examiner…