An emergency stop should be carried out on one third of tests chosen at random. It can normally be carried out at any time during the test; but the emergency stop exercise MUST be carried out safely where road and traffic conditions are suitable. If an emergency has already arisen naturally during the test this special exercise is not required; in such cases the candidate should be told and a note made on the DL25.
With the vehicle at rest the examiner should explain to the candidate that they will shortly be tested in stopping the vehicle in an emergency, as quickly and safely as possible.
The warning to stop the vehicle will be the audible signal “Stop!” together with a simultaneous visual signal given by the examiner raising the right hand to face level, or in the case of a left hand drive vehicle, raising the left hand. This should be demonstrated.
The examiner should explain to the candidate that they will be looking over their shoulder to make sure it is safe to carry out the exercise, and that they should not preempt the signal by suddenly stopping when the examiner looks round, but should wait for the proper signal to be given. To minimise the risk of premature braking, examiners are advised to ask the candidate if they understand the ES instructions.
The emergency stop must not be given on a busy road or where danger to following or other traffic may arise.
It is essential that examiners take direct rear observation to ensure that it is perfectly safe to carry out the exercise. They must not rely on the mirrors.
If the exercise cannot be given within a reasonable time the candidate should be asked to pull up, care being taken to choose the right moment as the candidate will have been expecting the emergency stop signal and may react accordingly. They should then be advised that the exercise will be given later and that they will be warned again beforehand. Alternatively, if conditions ahead are expected to be favourable, they should be reminded that the exercise will be given shortly, and the instructions repeated if necessary.
If a candidate asks whether they should give an arm signal, they should be told that the command to stop will be given only when it appears that no danger will arise as a result of a sudden stop, but that they should assume that an extreme emergency has arisen and demonstrate the action they would take in such a case.
The emergency stop exercise must not be used to avoid a dangerous situation.
ABS – Anti-lock braking system.
Note: Anti-lock braking systems (ABS) are being fitted to an increasing number of vehicles. Examiners should not enquire if a vehicle presented for a test is fitted with ABS.
Most ABS systems require the clutch and footbrake to be depressed harshly at the same time to brake in an emergency situation; therefore a fault should not be recorded purely for using this technique with a vehicle fitted with ABS on the emergency stop exercise. On the emergency stop exercise, under severe braking, tyre or other noise may be heard, this does not necessarily mean the wheels have locked and are skidding. Examiners should bear these points in mind when assessing the candidate’s control during this exercise. Further advice regarding ABS is given in the DVSA publication ‘driving the essential skills’.
The above is taken from The Driving Examiners Manual.
https://www.gov.uk/guidance/guidance-for-driving-examiners-carrying-out-driving-tests-dt1
Where appropriate it has been reformatted and edited so it only refers to the driving of ordinary cars (class b).
