Association of Chief Police Officers Traffic Committee
Enforcement Technology National Guidance Manual

ENFORCEMENT TECHNOLOGY DEVICES -OPERATIONAL GUIDELINES INTRODUCTION

The Road Traffic Offenders Act 1988 requires the type approval of radar speed meters and the Road Traffic Act 1991 expands that provision to allow for the type approval of other devices used for the enforcement of road traffic law. While type approval provides an assurance of the technical accuracy and reliability of a device, devices do need to be properly used. It is considered that the 'reliance on manufacturers instructions alone is not sufficient and that operational standards need to be laid down by the police in consultation with the Police Scientific Development Branch (PSDB).

Consequently the ACPO Standing Sub Committee on Road Traffic Enforcement Technology, under the auspices of the ACPO Traffic Committee, was given the task of preparing this document. In this respect officers with specialist knowledge of individual devices were drawn from various forces. The content of the document has been accepted by ACPO as to the operational standards and to be read in conjunction with manufacturers instructions.

Where these standards vary to that laid down by manufacturers the ACPO document will take precedence.

Forces should also have regard to the Home Office circulars which have and are to be issued on the installation, use and procedures for such devices. Circulars on the same subject are to be issued to highway authorities and magistrates courts.

TRAINING

This document should be used in conjunction with manufacturers instructions as the basis for training in respect of all road traffic enforcement technology equipment.

A time period for training has not been specified as this must depend upon a number of factors including the ability of the officer(s), numbers to be trained and the type(s) of equipment concerned. What has been laid down however, are the training objectives for each type of device.

Forces should ensure that sufficient staff are available as trained instructors who ideally should also have a wide range of operational experience. This may be achieved in the force concerned or by arrangement with another police force which has an established training programme in operation. Any guidance in this respect can be sought from manufacturers or The Standing Committee on Road Traffic Enforcement Technology Secretariat at Middlemoor, Exeter (Devon and Cornwall Constabulary, telephone number (0392) ******).

It is suggested that the training programme is placed under the control of a supervisory officer who will ensure that standards are maintained.

At the successful completion of the training a certificate of competence in respect of the use of the device(s) concerned should be issued to the officer. (Appendix 'A' refers).

SPEED DETECTION USING CALIBRATED SPEEDOMETER
FITTED TO PATROL VEHICLE

This type of check, commonly known as the "follow check" has been used by police forces for a number of years and is readily accepted by the courts and motoring public alike.

MEANS OF CHECK

The patrol vehicle ideally should be fitted with a certified calibrated speedometer which is regularly tested in accordance with Force instructions.

The checking vehicle should be positioned to the rear of the suspected offending vehicle so as to maintain, throughout the check, an even distance between the vehicles.

Speedometer readings should be taken throughout, preferably related to readily identifiable points passed.

MINIMUM DISTANCE

It is the view of ACPO Traffic, the recommended minimum distance for such a check be 2/10 of a mile.

SPEEDOMETER ACCURACY

The patrol vehicle speedometer should be checked for accuracy at the end of a tour of duty after detection of an offending vehicle. This will be in accordance with Force instructions utilising either certified measured distances or a rolling road type device. The speeds for the check being comparable with the speeds the subject of the report (within the 70 mph barrier) and be within + or - 2 miles per hour.

RADAR - GENERAL
1, THE DOPPLER PRINCIPLE

1 .1

All radar speedmeters currently used by United Kingdom forces rely on the doppler effect for their operation.

1.2

The doppler effect (named after a nineteenth century Austrian Physicist) occurs when a wave source and an observer are in relative motion to each other, the frequency of the waves appears to change: the frequency increases when the source of the waves and the observer approach one another and decreases when they move apart. (Figure 1).

1.3

The doppler effect can occur for any kind of wave, sound, light or radio.

1.4

This effect is most simply described by considering a listener standing on a railway platform hearing the siren of an approaching train.

1.5

The frequency (pitch) of the siren heard by the listener is higher than that heard by the train driver.

1.6

When the train has passed the frequency will sound lower to the listener.

1.7

The effect is equally true for radio waves

1.8

For a doppler radar speedmeter, a signal consisting of a narrow high frequency radio beam is transmitted along the road. A vehicle approaching along this beam will reflect some of the signal back to the system.

1.9

Because of the doppler effect the frequency of the returned signal will be higher than the transmitted signal.

1.10

The meter receives the reflected signal and measures the difference in frequency. The change in frequency is proportional to the speed of the vehicle. The meter then converts this information into miles per hour and shows it on a display.

2, RADAR COVERAGE

2.1

The meter will always display the speed of the strongest returned signal. When two cars of similar size are approaching the meter it may display the speed of the nearer vehicle.

2.2

The signal received by the radar not only depends on the distance of the vehicle, but also its size, so that a large lorry some distance from the meter may return a signal stronger than a small car closer to the meter.

FIGURE 1
THE DOPPLER EFFECT EXPLAINED THE SPEED OF A VEHICLE IS ARRIVED AT BY COMPARISON OF SIGNAL SENT AND SIGNAL RECEIVED

2.3

The radar meter has an aerial which forms the radar signal into a beam so most of the signal is sent out directly ahead of the meter, but some of the signal spreads out on either side of the main beam. The coverage of the radar depends on several factors, which include:

(a) the radar power
(b) receiver sensitivity
(c) aerial characteristics
and also
(d) the size of the target vehicle
(e) its distance from the observer
(f) its position in the aerial beam

2.4

Figure 2 shows the effective detection range for different sizes of vehicle. It can be seen from the diagram that the coverage in terms of road distance and width depend the size of the vehicle.

2.5

Different models of radar will have different coverage diagrams but figure 2 may be taken as typical for hand held radars.

3, COSINE FACTOR

3.1

Radar will only record the true speed if the radar is in the line of the vehicles path. The vehicle may be either approaching or receding.

3.2

If the radar is positioned at an angle to the path of the vehicle, the apparent speed of the vehicle is reduced. The reduction in speed is proportional to the cosine of the angle.

3.3

For an angle of 15 degrees a speed of 38mph will be recorded for a vehicle travelling at 40mph.

3.4

THE COSINE FACTOR IS ALWAYS IN FAVOUR OF THE DRIVER.

3.5

Roadside radar devices have inbuilt electronic circuits to correct the cosine factor provided the unit is aligned correctly in accordance with manufacturers instructions.

4, REFLECTIONS AND SITE SELECTION

4.1

As described previously, the radar signal is reflected from a moving vehicle. The sign can also be reflected or scattered by stationary objects such as road signs, hoardings or pillar boxes. As these objects are stationary, no doppler effect will occur and no reading will appear on the display.

4.2

However, these objects can act as radio mirrors and reflect signals from moving vehicles outside the area of the coverage diagram (Figure 2). For example, the signal could be reflected around a bend in the road and measure the speed of a vehicle not visible to the radar operator.

Fig. 2, Coverage Diagrams for a typical hand-held doppler radar
The figure shows three superimposed diagrams. The radar meter can detect each vehicle within the boundary shown, vehicle A is within its coverage area, it will not register on the meter beyond 200m. The larger vehicle B can just be detected out to 300m.
Vehicle C is just entering its coverage area.
This diagram shows the effective detection range for different sizes of vehicle. It can be seen that the coverage in terms of road distances and width will depend on the size of the vehicle. Different makes of radar will have different coverage diagrams, but the illustration above is typical of a hand-held radar speedmeter.

4.3

Because of the scattering effect, signals returned to the radar in this manner will be very weak and far less than the signal returned from a vehicle directly in the radar coverage area. It is extremely unlikely that a reflected signal will have any effect while a vehicle measurement is being made.

4.4

However, sensible precautions should be taken to select a site free from reflecting objects and with a clear, unobstructed view of the road.

4.5

The ability of objects to reflect radar signals vary. A flat metal surface, like a hoarding, will reflect more efficiently than a run of trees, which would absorb and scatter the signal.

4.6

To act as a radar mirror, lamp posts and telephone poles must: (a) be at the correct angle (b) occupy a large portion of the field of view c) be reflecting a fairly large vehicle

4.7

It is therefore an important requirement to check a site before starting measurements. The operator should always select a site with a clear view of the oncoming traffic which is free of any large objects such as:-
(a) bus shelters
(b) large road signs
(c) metal fences/crash barriers which are close to the radar.

4.8

To avoid multiple reflections the radar must not be operated under or through bridges or railway arches.

4.9

The selected site should be assessed for reflections by facing the traffic flow and aiming the meter along the road when no vehicle is in view.

4.10

Traffic passing to the side and rear of the operator may cause a reading if a reflected surface is present. A different site must be selected if the operator is not completely satisfied in this connection.

4.11

Radar equipment in the manned mode must not be operated for enforcement purposes in the central reservation of a dual carriageway or motorway when the two carriageways are in use. It may, however, be so operated when installed by manufacturers for unmanned use within cabinets.

4.12

To summarise:
(a) The site must be tested and therefore clear of any obvious source of interference.
(b) The site must be clear of nearby reflectors.
(c) The operator must have a clear view of the road.
(d) The operator must position himself at the side of the road, facing the oncoming traffic.

5, RADIO INTERFERENCE

5.1

It is impossible to obtain complete immunity from radio interference. The best protection is the use of the meter in the hands of a trained and certified operator.

5.2

If radio interference is present the speed display will show a reading. The reading may be steady, or erratic depending upon the type of transmitter. Interference effects will only occur when the radar meter is close to the transmitter or the transmitter is very powerful. It is not possible to lay down a strict criteria for safe operating distances from transmitters. The strength of the interference depends on several factors, such as transmitter frequency, type of aerial and modulation system.

5.3

Police radio transmitters, whether hand held or car mounted, must not be used at the moment a vehicle speed is being measured. It is perfectly safe to leave the receiver on provided the volume level is at a usable minimum. The use of a repeater radio in the vicinity of a radar speed meter should be avoided.

5.4

When selecting a measuring site, places with view of:-
(a) high voltage overhead lines
(b) transmitting masts or towers
(c) Airports or harbours
(d) where high power radar transmitters may be expected to operate:-
must be treated with extra caution.

5.5

With the current popularity of Citizen Band radio transmitters, it may be difficult in a suburban street, to tell the difference between transmitting aerials and domestic receiving aerials.

5.6

It is important, therefore, to ensure that no interference is present by carrying out repeated checks (in accordance with the instructions for a particular device) to see that the meter display is blank and/or that the radio interference indicator is not indicating that interference is present when set in the measuring mode and that no vehicles are present in the field of view. This is the ultimate assurance that the meter is unaffected by radio interference.

5.7

Some meters are fitted with RFI protection circuits. The operation is described in the manufacturers appendix relevant to the device.

6, RADIATION HAZARD

6.1

The Microwave radiation from radar devices having United Kingdom Type Approval, comply with standards which are designed to ensure safety when operating the device. The maximum level of radiation when transmitting is below the United Kingdom recommended level, and the devices can be considered absolutely safe for police use. No particular precautions are considered necessary. However, to avoid even low level exposure it is recommended that the radar aerial should not be held nearer than 25cms to the body.

6.2

The National Radiological Protection Board lay down guidelines in respect of maximum exposure levels to radiation. The type approval requirements demand that these levels are not exceeded.

7, CARE AND MAINTENANCE

7.1

A radar device is a precision instrument. It has been constructed robustly but emphasis must be made on the need for careful and sensible handling.

7.2

Devices are supplied with a protective carrying case which should always be used when the device is not in operation. In respect of roadside radar devices before re-packing both power and display cables MUST be disconnected.

7.3

Should a device be dropped or damaged it must be checked immediately using the standard calibration method. Any apparent defects must be reported and the device taken out of service forthwith.

7.4

The charging and maintenance of power packs is governed by manufacturers instructions.

7.5

Repair and maintenance should only be undertaken by a competent organisation approved by the Home Office, manufacturer or his appointed agent.

8, ANNUAL CALIBRATION

8.1

Any repair or calibration shall be carried out by the manufacturer, his appointed agent, or a suitably qualified technician offering appropriate evidence of technical and professional competence. Such persons shall keep accurate records which shall be open to inspection by the Home Office

8.2

The speed meters shall be annually calibrated and a certificate should be issued to this effect and held by the police. A visible sticker showing the date of calibration should be fixed to the meter.

HAND HELD RADAR
9, RECOMMENDED OPERATING TECHNIQUE

9.1

The testing procedures laid down by manufacturers for each individual device must be scrupulously adhered to. In addition the device should be checked against a police vehicle fitted with a certified calibrated speedometer at a speed compatible with the sites to be checked prior to and after operation. As this equipment does not have to be reassembled at each site this check should be at the commencement and completion of tour of duty to within an error margin of + or - 2 miles per hour.

9.2

Hand held radar speedmeters should only be operated by an officer on foot:-
(a) The only enforcement situation should be when one vehicle is isolated in the field of view of the radar device and the operator.
(b) The device should be pointed directly at the approaching target vehicle, parallel to the roadway, eliminating any significant up or down tilt.
(c) Once a reading has appeared on the display, the radar device should be held steady, pointing along the road for a duration of not less than three seconds. During this period a steady reading must be obtained which equates to the observations of the operator.
(d) 'Steady' in this context can include accelerating or decelerating readings:
e.g. readings of 45-45-46-47 or 47-46-45-43 are acceptable.
(e) If the reading jumps by several mph:
e.g. 47-40-35-47 or if for any reason the operator has any doubt as to the validity of the reading, the check must be aborted.
(f) Once the operator is satisfied that the reading showing on the display corroborates his personal observations and IS the speed of the target vehicle and WHILST THIS READING IS STILL VISIBLE ON THE DISPLAY, the trigger button must be activated to lock the display. (Where appropriate).
(g) The reading can be cleared following the manufacturers instructions for the particular device being used.

Note: Hand held radar devices are not designed for use indoors. Any demonstrations should be carried out in the open and at the roadside following normal operating procedures.

9.3

SCIENTIFIC ADVICE IS THAT THE OPERATOR AND THE DEVICE MUST BE OUT SIDE A VEHICLE, WITH A POWER SOURCE INDEPENDENT OF A VEHICLE.

10, DISTANCE AWARENESS

10.1

When operating the device and during the preparation and presentation of evidence, it is essential to visualise distances that will be travelled by the target vehicle during each check

10.2

At 60 mph the target vehicle will cover 80.4 metres in 3 seconds. One also has to take into account the observation time for an opinion to be gained. To cause the vehicle to stop will require another 73.1 metres. It is therefore imperative that these matters of physical fact be recognised and understood. For ease of reference and as a training aid, a time, speed and distance chart is attached (Appendix 'B').

11, MULTIPLE VEHICLES

11.1

Radar speed meters are designed to measure the speed of one vehicle at a time. Should there be more than one vehicle present in the radar field of view it is possible for the device to detect two different signals and alternately display different speeds as described in 9.2(e), in which case the check MUST be aborted.

11.2

With vehicles of similar size within the range of the radar, the meter may read the nearer vehicle, but not necessarily, since the reflected signal from a vehicle is very complex and fluctuates rapidly as the view of the vehicle changes slightly. AN OPERATOR MUST NOT MEASURE AND MAKE DETECTIONS FOR PROSECUTION WHEN MORE THAN ONE VEHICLE IS WITHIN THE RADAR DETECTION RANGE.

11.3

It is quite possible for the signal from a large vehicle some distance behind a smaller vehicle to override the signal from the nearer vehicle.

12, EVIDENCE

12.1

Presentation of Evidence

(a) The eventual success of any prosecution depends upon accurate observations by the officer operating the device and the professional presentation of evidence before the Court. It is in this area that the integrity of devices will be closely scrutinised.
(b) Operators should not only record evidence concerning the target vehicle, such as speed, direction of travel etc., but additionally, note the presence of any other vehicle in the vicinity, which may be used in defence when contradicting prosecution evidence.
Note: The need to document all evidence is obvious as the memory of the operator must dim with the passing of time.
(c) It must be remembered that the evidence of the equipment is only CORROBORATION of the operators prior opinion that the target vehicle was travelling in excess of the permitted speed limit for the road or class of vehicle.
(d) If the operator has any doubt as to the validity of the reading obtained by the device in comparison to his personal estimation of the speed of the target vehicle, then he will abort the check.
(e) Operators of devices should normally do so from positions where they will be clearly visible to the public.
(f) The target vehicle must be kept within direct sight of the operator of the device at all times throughout the period of observation and check.
(g) Positive identification of the target vehicle must be made by the device operator, to enable any enforcing officer to identify and process an offender.
(h) Whilst no legal requirement exists for the accused driver to be shown the speed recorded on the device, whenever this is possible he should be given that opportunity.
(Westwater -v- Milton, 1980).
(i) A trained police operator must necessarily be aware of the basic technical functions of the device. However, it is stressed that he is not technically qualified to give evidence on principles of the system nor the internal workings of the device. If such evidence is required, then an expert witness must be called.

ROADSIDE RADAR

Models exist that can measure either approaching or receding traffic by the operation of a switch on the unit as per manufacturers instructions.

Meters will operate at all times of day or night and in most weather conditions. (The equipment is Type Approved from -10 to +40C).

13, CHOICE OF SITE

13.1

Satisfactory operation of the device depends on the correct positioning and alignment of the radar. It should be positioned as near the traffic flow of interest as is convenient and it should face a straight section of road.

13.2

The radar is primarily intended to be operated at the side of the road adjacent to the traffic flow to be monitored, with that traffic flow either approaching or receding from the radar, as shown in Figures 3 and 4.

13.3

It should be noted that the traffic moving in the opposite direction to that of interest, will also be detected by certain models. The use of the range control will minimise the incidence of unwanted readings from traffic remote from the radar.

13.4

Certain models will only respond to vehicles travelling in the direction selected by a control switch on the device.

13.5

It is possible to monitor traffic speeds in both directions or to use the radar on the side of the road remote from the traffic flow of interest but care must be taken that small vehicles in the furthest lane are not out of range of the radar. The normal practical maximum width of road for detection of all vehicles is 3 lanes, with the radar situated within 4 feet of the edge of the road.

13.6

Radar equipment in the manned mode must not be operated for enforcement purposes in the central reservation of a dual carriageway or motorway when the two carriageways are in use. It may, however, be so operated when installed by manufacturers for unmanned use within cabinets.

14, SETTING UP THE RADAR METER AND OPERATION

14.1

This should be in accordance with the manufacturers instructions for the unit concerned.

14.2

The device MUST NOT BE USED for speed enforcement purposes with a display extension lead due to the possibility of radio interference other than that supplied by manufacturers and agreed with PSDB.

14.3

Internal checks as per manufacturers instructions should be carried out at each site prior to and after operation. In addition to the checks recommended by the manufacturer, the display/test display button should be operated to ensure that the digital display on the device is in perfect working order.

14.4

The accuracy of the meter should be checked by driving a vehicle with a calibrated speedometer through the beam at a predetermined speed, at the commencement and completion of operations at each location (the speed being compatible with the site being checked).

 

14.5

THE DEVICE MUST NOT BE OPERATED FROM WITHIN A VEHICLE.

14.6

Readings should only be considered valid if the operator(s) are sure that only one vehicle passed through the beam. It is therefore important that the operators have a clear view of both the area of road covered by the beam and of the speed display.

14.7

The road area covered by the radar should be in view of the operators. Where physically possible the site should be selected so that the speeding vehicle, the display and stopping officers can all be seen clearly by the radar operator.

15, NORMAL OPERATION

(a) The ideal enforcement situation is when only one vehicle is isolated in the field of view of the radar device and the operators.

(b) If there is more than one vehicle present, the operators must measure only one vehicle and they must ensure that the proximity of the other vehicles is such that a clear reflected signal can be obtained of the target vehicle.

(c) Under no circumstances must other moving vehicles, (travelling in either direction) be between the operators and the target vehicle.

(d) If for any reason the operators have any doubt as to the validity of the reading, the check must be aborted.

OBJECTIVES FOR TRAINING IN RESPECT OF
ALL RADAR SPEED OPERATORS

The ACPO recommendations are that the duration of training should be of a period of time to enable an operator to qualify for the award of Certificate of Competence.

At the conclusion of the course the student will:-
1 Know the basic principles of radar speed meter technology as outlined in this document and manufacturers instructions.
2 Be able to carry out checking, accuracy tests and operating procedures.
3 Be competent in the presentation of evidence and court procedures.
4 Have full knowledge of site selection and testing.
5 Have carried out practical demonstrations on site.
6 Have been fully assessed as an operator.

TYPE APPROVED RADAR DEVICES
HAND HELD

1 MUNIQUIP KGP
2 KUSTOM HR4
3 KUSTOM HR8
4 KUSTOM FALCON
5 KUSTOM ROADRUNNER
6 SPEEDAR SR1

ROADSIDE
1 GATSO MINI RADAR MK3/MK4
2 GATSOMETER BV TYPE 24+AUS

TIME/DISTANCE TYPE DEVICES

The TIME/DISTANCE method of speed detection may be utilised when operating ACPO approved devices (see note ACPO APPROVED TIME DISTANCE DEVICES).

The manufacturer's instructions MUST be adhered to in respect of switch operation and methods of calibration.

16, HOME OFFICE TYPE APPROVAL

16.1

Unlike the radar devices, time/distance calculating equipment does not require type approval. However, as new equipment becomes available it will be evaluated by various forces and recommendations as to its suitability submitted to ACPO Standing Sub Committee on Road Traffic Enforcement Technology who will advise as to its future use.

16.2

A number of these devices are capable of being linked into video recording equipment. This in no way effects the operation of the device but merely provides pictorial evidence of that observed through the camera and evidence on tape of the operation of the time distance mechanism. It is imperative however that PSDB have approved the interface linkage between the device and the video.

17, BASIC PRINCIPLES

17.1

The detection of speeding offences using the equation:

Speed =

Distance

Time

is a long established practice.

Initially this was carried out by use of a certified stopwatch and the odometer of the patrol car. Whilst this principle remains, technology has allowed for the introduction of sophisticated equipment which has proved to be far more efficient and accurate. The operation of the devices simply involves the operation of a distance switch and a time switch, in the appropriate sequence. This calls for a high level of accuracy and in order to achieve it, a good deal of practice is required.

17.2

The checking of a target vehicles speed can be done by a number of methods.

17.3

Where a vehicle is, in the opinion of a police officer, travelling at an excessive speed the device is used as corroboration.

17.4

In order that this can be done, the target vehicle needs to be checked between two reference points. The points used are best defined as "an identifiable point on or near the carriageway, either permanent or temporary:-
a) Which either casts a shadow so as to strike a moving vehicle, or which is so placed that the shadow of a moving vehicle strikes it or its shadow, or
b) where there is physical contact between the road wheels of the moving vehicle and a reference point e.g. change of surface, drain or
(c) where the target vehicle and the police vehicle are side by side

There are five alternatives:-
(i) a moving shadow on a stationary object.
(ii) a moving object on a stationary shadow.
(iii) a shadow-to-shadow contact.
(iv) physical contact of vehicle wheels with reference point.
(v) both vehicles are side by side. By using reference points which fit this definition we can eliminate any uncertainty.

17.5

It is important to remember that the police vehicle MUST pass between the same points as the target vehicle. This is essential as the distance information is taken from the police vehicle. When the police vehicle has travelled between the two points and the distance switch operated, on at the first point and off at the second point, the device then knows the distance between the points. As the target vehicle travels between the same two points, the time switch is operated. The switch being switched on at the first point and oft at the second point. The device now knows the time the target vehicle took to travel between the two points.

17.6

The device now has both parts of the equation required to calculate the target vehicle's speed. This is done in a fraction of a second and visible on a digital display.

17.7

If for any reason the operator has any doubt as to the validity of the check, it must be aborted.

18, TYPES OF CHECK

18.1

FOLLOW CHECKS.

This type of check is carried out when the police vehicle is following the target vehicle.

As the target vehicle passes the first reference point, the time switch is turned on.

As the police vehicle passes the same reference point, the distance switch is turned on.

As the target vehicle passes the second reference point, the time switch is turned off. The device now knows the time the target vehicle took to travel between the two reference points.

As the police vehicle passes the second reference point, the distance switch is turned off. The device now knows the distance between the two reference points that the target vehicle has travelled.

18.2

PRE FED DISTANCE CHECK

This check is carried out when the police vehicle travels between the two reference points. Turning the distance switch on at the first point and off at the second point.

The police vehicle then parks in a position that the two reference points can be clearly seen by the operator.

As the device knows the distance between the reference points, as a target vehicle passes between the points the time switch is turned on and off. The device can then calculate the speed. Providing the distance information is not cleared from the device the police vehicle can remain parked and, by clearing the time information only, another target vehicle can be checked.

18.3

BEING FOLLOWED CHECK

This check is carried out when the police vehicle is travelling in front of the target vehicle, that is the target vehicle is approaching from behind at a speed which is excessive,

The police vehicle will travel between the two reference points, turning the distance switch on and off. The device now knows the distance travelled.

As the target the vehicle, still approaching from the rear, passes the same points the time switch is turned on and off. The device now knows the time taken to travel between the reference points. The device knows the distance and time and can calculate the speed. NB When using this method operators should guard against any suggestion of being "agent provocateur".

18.4

CROSSING CHECK

This check is carried out when the police vehicle is stationary at the mouth of a junction. The target vehicle is seen approaching crossing the front of the police vehicle.

As the target vehicle passes the front of the police vehicle the time switch is operated at an identifiable reference point. The police vehicle then moves off behind the target vehicle, operating the distance switch at the same reference point.

With the police vehicle now following the target vehicle and both time and distance switched on, the completion of the check is the same as the follow check".

18.5

DIAL IN DISTANCE

This mode enables a known distance previously measured by the device to be fed into the computer without the need to drive again over the route. NB Particular care must be exercised where shadows are used as these will change with the movement of the sun. Simply record the distance on the same push button switches as used for calibration purposes. This procedure can also be used with the control module removed from the car and plugged into the portable battery pack.

18.6

THE MINIMUM DISTANCE FOR ANY CHECK IS GENERALLY1/8 OR .125 OF A MILE.

However checks over a shorter distance, down to an absolute minimum of 0.07 of a mile are permissible under the following circumstances:-

a) The general minimum can only be reduced for Pre-fed or Dial-in Distance Checks.
b) The reference points at both the start and end of the check are physical features on the road surface which provide a clear and visual contact. (e.g.. white line/change of surface) NOT shadows.
c) The maximum speed limit at the site does not exceed 40mph.

trainers are to be satisfied that operators carrying out reduced distance checks are capable of performing the function professionally (i.e. maybe specialists for urban work)

Over short distance checks operators should consider other type approved devices that will provide a specific measurement.

19, CALIBRATION

19.1

In order to maintain accuracy these devices must be calibrated in accordance with the manufacturer's instructions. Full calibration MUST be carried out (a) On initial installation, (b) Following removal and reinstatement, (c) Following the fitment of new tyres and (d) IN ANY CASE AT WEEKLY INTERVALS.

19.2

In order to establish the ongoing accuracy of the device a check MUST be carried out at the commencement of each tour of duty and at the end of that tour of duty if it has been used to detect an offence. This will be either (a) Calibration check (all types), (b) Double Switching (VASCAR/SPDM).

19.3

If the device is found to be inaccurate, then not only must the defect be remedied but any offences detected since the previous accuracy check should be reviewed as it is not known at what point the equipment became defective.

TRAINING OBJECTIVES

It is recommended that all training be carried out using similarly equipped vehicles with car to car communications.

At the conclusion of the course students should:-
a) Understand the principles and operation of the speed detection device(s).
b) Be able to calibrate the device(s).
c) Be able to carry out calibration checks.
d) Be able to perform speed checks in accordance with the test criteria.
e) Have developed early recognition of reference points including shadow principles.
f) Be aware of evidential requirements and any national/force policies.

TEST CRITERIA

Students will be required to perform five examples of each of the methods taught. No one check may exceed a two miles per hour error and in the case of VASCAR/POLICE PILOT/ SPEED MARSHALL the average error must not exceed .75 mile per hour. See paragraph 18.6 re shorter distance checks.

ACPO APPROVED TIME DISTANCE DEVICES

VASCAR, VASCAR 4000, VASCAR 400 SPECIAL, VASCAR 5000, VASCAR 5000 SPECIAL
SPDM
POLICE PILOT
SPEEDMARSHAL

 (as of 1/1/93)

ACPO APPROVED SENSOR OPERATED DEVICES
(SUB-JECT TO TYPE APPROVAL)

TRUVELO M4 SQUARED
SPEEDMAN
SPEEDMASTER DS2
MERCURY (modified version)

 

PHOTOGRAPHY ATTACHMENTS FOR SPEED DETECTION DEVICES

24, INTRODUCTION

24.1 The devices referred to in this document may be capable of producing evidence by means of photography.
24.2 The absence of such a camera will in no way affect the type approval of the device should operation be decided upon in the non photographic mode. Where such a camera has been attached the photographic elements of that system will require type approval.
24.3 Should a camera attachment be utilised for evidential purposes then in the police manned mode one photograph will suffice. If the device is unmanned then a second method of speed measurement is required thus providing a means of checking the accuracy of the device. (See paragraph 26.2).
24.4 The technical requirements of such devices are laid down in the Home Office Police Scientific Development Branch Speedmeter Handbook. The document sets out the type approval requirements with which the manufacturer will have to comply.

25, MANNED DEVICES

25.1 The camera attachment does not affect the procedures for the operation of the device concerned except that the camera should be in the operational mode to record the checking procedures on the photograph.
25.2 A check of the accuracy of the equipment should be carried out at the commencement and termination of each period of operation. Where the equipment concerned has to be dismantled and reassembled this should be at each site.
25.3 In relation to equipment which does not have to be dismantled internal checks should take place at the beginning and end of the tour of duty and in any case (where the equipment has been used) every 24 hours. As regards equipment which has to be dismantled the checks should take place at each site. Similar external checks should take place utilising a police vehicle fitted with a certified calibrated speedometer at speeds compatible with the site to be checked.

26, UNMANNED/AUTOMATIC DEVICES

26.1 These devices should be installed following consultation between the highway authority, manufacturers and the police and in accordance with guidance to be issued by the Home Office and Department of Transport.
26.2 A requirement of the type approval is that unmanned/automatic devices should have a second means of checking the primary speed measurement. One such means offered by manufacturers at this time is the taking of two photographs of the offending vehicle at a known time apart. Full details of the means of achieving this check are required by type approval to be included in the manufacturers instructions for the device concerned

27, HANDLING OF FILM

27.1 This should take place in accordance with any instructions laid down by individual manufacturers.
27.2 The legal requirement is that a notice of intended prosecution should be served within 14 days of the offence on either the driver or registered keeper. It is therefore important that devices are checked regularly in order that the registered keeper can be identified and served with a S172 notice/notice of intended prosecution within the 14 day period.
27.3 As regards manned devices, films may contain details of offenders from differing sites on the same film due to the device being moved from site to site.
27.4 Operators should ensure that the correct details of sites have been recorded both manually and on the photographs.
27.5 In the event of the device failing to record either time/date/speed etc on the photograph then unless the operator has recorded those missing details manually the check will have to be disregarded. (This problem will not be evident until the film has been developed).
27.6 In the event of an occurrence as above involving an unmanned device then obviously it will be of no evidential value and will have to be disregarded.

28, FILM PROCESSING

28.1 It is recommended that the developing of the films be undertaken by a police photographic unit (either force or nationally based) or alternatively a private confidential service offered nationally.
28.2 It has been identified that some police photographic units may not have the necessary equipment to process films of the lengths produced by these devices. It is therefore recommended that if this be the case that the lengths be reduced to workable units by cutting at 450 diagonally hence through a frame. (These actions will ensure that there can be no accusations of tampering with the film during the developing process.)
28.3 There will be no need for forces to make prints at this early stage as viewing for prosecution purposes will be undertaken utilising the negatives.
28.4 There will be no need to prove continuity in respect of these films as each will identify the site and date by means of the diode array which produces this information on each photograph. In addition the photograph will identify specific offenders through identification of the vehicle registration mark. Although this be the case forces should avoid excessive handling by numerous persons in the processing of the films.

 

29, VIEWING FOR PROSECUTION PURPOSES

29.1 Numerous viewing devices are available on the market however it is recommended that whatever device is utilised it should have the capability of dealing with a large reel of negatives; possess a zoom facility and be capable of reversing the film polarity as on occasions some vehicle registration marks are clearer in the negative mode. Where a vehicle registration mark cannot be identified by the zoom facility and/or adjusting the contrast/brightness, or reversing the films polarity, the reading will be disregarded (PNC will not be utilised to establish identity by a search of a range of numbers/letters and clarifying by make /colour). Accurate visual identification should however be verified by confirming make and colour on PNC.
29.2 Operators should have the Chief Constable's authority to carry out this task; prosecution decisions being made in accordance with force and national guidelines.
29.3 A close examination should be made of the film by the operator with a view to ensuring that it gives:-
a) Clear and unambiguous negatives of the offence.
b) All the necessary information as required by type approval is recorded.
c) Where there is a suggestion in the negative that two or more vehicles are or maybe in the measurement field the reading should be disregarded.
29.4

Secondary check

In the case of an unmanned device measurements are taken in respect of three vehicles on the film (beginning - middle - end) choosing clear images of the vehicle with defined edges to the frame. The method adopted must be in accordance with manufacturers instructions and verified by P.S.D.B.

NB In respect of the photograph measurement method the measurements should take place utilising an optical projector system (not video) with the assistance of a metal rule, digital calliper or the like duly certified by a trading standards office. In the event of two or more of the readings being outside the 10% accuracy band the film should be disregarded. If only one of the readings is outside the 10% band a further three checks should be undertaken all of which must be within the 10% accuracy band.

30, STORAGE OF INFORMATION

30.1 Forces and highway authorities will wish to consider the logging of information produced by such devices for statistical and easy reference purposes. This may be manual and/or computer based.
30.2 The evidence produced by these devices will have to be retained and stored for evidential purposes. This should be in accordance with individual force instructions following consultation with local CPS.

PROSECUTION PROCEDURES

Specific Home Office circulars on the use of technology will be issued in due course which will deal with prosecution procedures to be followed by the police, Crown Prosecution Service and Magistrates Courts. ACPO policy in this respect already exists. However, new guide lines will have to be issued particularly in regard to the use of the conditional offer.

 

LASER/OPTICAL OPERATED SPEED DETECTION DEVICES

31, INTRODUCTION

31.1 Laser /optical devices are capable of being manufactured for handheld, vehicle mounted (when stationary) or roadside use in both manned and unmanned mode, with or without camera attachments.
31.2 The handheld devices, on occasions, have the appearance of a firearm. It is therefore important that this fact is borne in mind when operating such units. The operator must be clearly visible to the public and the target vehicle throughout the check. Devices should be operated in accordance with manufacturers instructions.

32, HANDHELD

32.1 The handheld device functions by emitting pulses of infra red laser beams which are targeted at the vehicle whose speed is being measured.
32.2 Measurement of speed is performed by aiming the device at the target vehicle in the area around the registration plate and where necessary pressing the trigger button. It is important that the beam is held steady on the target area to avoid any 'slip factor'. When sufficient pulses of light have been emitted and have returned and are within the in built tolerances and checks then a reading is displayed on the device. The speed recording can be locked into the display by activating the trigger button in accordance with manufacturers instructions where necessary.
32.3 Devices are capable of recording approaching or receding vehicle speeds, this fact being clearly differentiated.
32.4 To assist the operators identification of the target vehicle the meters have electronic sighting devices (currently either "red dot" telescopic or "reticle sight" on head up displays) together with audible 'locked-on' tones where applicable.
32.5 Operators should bear in mind that the device confirms and corroborates prior personal observations.
32.6 Certain handheld laser speed detection devices have the ability to establish speeds of vehicles by calculating the time it takes a vehicle to travel over a known distance whilst in the time/distance mode. The time distance function should be operated in accordance with manufacturers instructions and ACPO guidelines as at pages 18-21 of this manual.
32.7 ACPO guidelines prohibit the use of handheld radar speed detection equipment for enforcement purposes from within a vehicle. Laser/Optical hand held devices may be used from within a vehicle but the beam will not be projected through glass or mirrors. The power source however can be taken directly from the vehicle or from an independent supply.

33, RANGE

33.1 Handheld devices are capable of measuring vehicle speeds from a minimum range of 50 feet to a maximum of 2,000 feet, recording speeds from a minimum of 5mph to a maximum of 299mph. Operators should avoid carrying out measurements for enforcement purposes at the extremity of the measurement field. Clearly the steadiness of sighting of the handheld device affects operating range, but does not affect accuracy. In any case the device will not display any speed reading unless a proper 'lock-on' has occurred.
33.2 The car/tripod mounted devices are capable of recording vehicle speeds from 1mph up to 620mph.
33.3 Heavy rain, spray or mist may reduce the range of the laser but will not effect the speed measurement.

34, COSINE/ANGULAR EFFECT

34.1 The handheld laser will only record the true speed if it is directed along the path of the target vehicle. The vehicle may be either approaching or receding.
34.2 If the laser is positioned at an angle to the path of the target vehicle, the displayed speed Is less than its actual speed. This reduction in speed is proportional to the cosine of the angle.
34.3 The angular effect or cosine error is always in favour of the target vehicle, whether the device is operated in the horizontal or vertical plain.
34.4 When operating handheld devices from the roadside the operator should be within 10 feet of the edge of the carriageway and beyond the minimum operating range (ie 50 feet).
34.5 When operating handheld devices from an over-bridge the operator must stand where possible over the centre of the carriageway being checked. In respect of minimum range, the operator must carry out a height check from the level of operation to the road surface directly below then multiply this by a factor of ten. This figure becomes the minimum distance for operation.

35, CAR/TRIPOD MOUNTED

35.1 These devices operate by measuring the time taken for vehicles to pass across two sensors emitted from the sensor box which is mounted within a vehicle or free standing. The device is positioned at right angles to the roadway. Current devices either use changes in ambient light levels to sense vehicle movements or red laser light beams across the roadway which also detects movement. These devices can be operated manually or independently with camera attachments. It is important that only one vehicle is within the measurement area when used for enforcement purposes.
35.2 Roadside/vehicle mounted laser/optical meters currently are designed to record vehicles travelling in one direction at a time. Where a device has a switch enabling vehicle speeds to be measured in both directions (either individually or simultaneously) it is important to site the device correctly and in accordance with manufacturers instructions. Where there is a camera attachment it should be correctly aligned.

36, EYE SAFETY

36.1 All laser devices tall within 'Class 1' which is the lowest classification of laser products in terms of relative potential injury to health. The Class 1' devices are completely safe for human exposure based upon current medical knowledge.
36.2 There are no special requirements except for principles of common sense, ie:-
(a) DO NOT stare directly into the beam.
(b) DO NOT stare at beam using binoculars, telescope, or other optical gain devices.
(Prescription eyeglasses, bifocals, etc. are not considered optical gain devices as they serve only to correct the focus of the eye to normal human vision.)

 

37, CARE AND MAINTENANCE

37.1 Periodic cleaning of external optical surfaces is recommended only when necessary, if evidenced by degradation in performance of unit or by visible contamination.
37.2 Cleaning should be undertaken by firstly gently brushing base debris from the optical surface and secondly by gently wiping in a circular motion using either a lint-free cloth or lens cleaning tissue, dampened with low-residue isopropyl alcohol. Excess rubbing should be avoided to attempt to clean scratches, pits and stains on optical surfaces as this will cause further damage.
37.3 The following guidelines must be adhered to:-
(a) When not in use, the protective lens cap (if applicable) must be installed and the device kept in a heavy duty case.
(b) When momentarily laying instrument down, care should be taken to keep optical surfaces from contacting other objects such as seat upholstery, belt, buckles, etc. which could scratch lenses.
(c) Instrument should never intentionally be pointed directly at the sun or any other source of intense light; doing so may cause degradation of the sensitive receiver resulting in loss of performance (vehicle headlights do not affect the device).
(d) Devices are supplied with a protective carrying case which should always be used when the device is not in operation. In respect of tripod/vehicle mounted devices, before repacking, both power and display cables must be disconnected.
(e) Some manufacturers supply a harness for carrying the device/power unit when not in operation.

38, CALIBRATION/TESTING

38.1 Due to the nature of the medium and systems used, these devices are CONTINUALLY SELF-CALIBRATING.
38.2 Calibration VERIFICATION is carried out:-
(a) By the device itself during its BUILT IN tests upon being switch 'ON' and,
(b) During and as part of the START and END of tour checks. A record of these checks will be made (ie in pocket note book).
38.3 Should a calibration defect arise, the device MUST be returned to the manufacturer or certified authorised agent before further use.
38.4 The speed meters shall be annually calibrated by the manufacturer or his agent and a certificate should be issued to this effect and held by the police. A visible sticker showing the date of calibration should be fixed to the meter.
38.5 The testing procedure as laid down by the manufacturer of each individual device must be scrupulously adhered to. These checks must be carried out before and after any check when enforcement has taken place and as follows:-
38.6 Handheld Device - Check against a police vehicle fitted with a certified calibrated speedometer at a speed compatible with the site to be checked prior. As this equipment does not have to be reassembled at each site this check should be at the commencement and completion of a tour of duty, to within an error margin of + or - 2 miles per hour.
38.7 Roadside/Tripod - The accuracy of the meter should be checked by driving a vehicle with a certified calibrated speedometer through the beam at at a predetermined speed at the commencement and completion of operation at each location (speed to be compatible with the site being checked).
38.8 Vehicle Mounted - If the equipment is dismantled after each operation the check should be in accordance with roadside/tripod guidelines, if not as handheld guidelines.
38.9 Some devices have the facility to measure distance and this should also be used to confirm accuracy following manufacturers instructions.

39, EVIDENCE

39.1

Presentation of evidence:-
(a) The eventual success of any prosecution depends upon the accurate observations by the officer operating the device and the professional presentation of evidence before the court. It is in this area that the integrity of devices will be closely scrutinised.
(b) Operators should not only record evidence concerning the target vehicle, such as speed, direction of travel etc., but additionally, note the presence of any other vehicle in the vicinity, which may be used in defence when contradicting prosecution evidence. (With accurate sighting this problem is unlikely to occur.)

NOTE: The need to document all evidence is obvious as the memory of the operator must dim with the passing of time.

(c) In respect of non photographic devices, it must be remembered that the evidence of the equipment is only CORROBORATION of the operator's prior opinion that the target vehicle was travelling in excess of the permitted speed limit for the road or class of vehicle. (Corroboration is not required for photographic devices.)
(d) If the operator has any doubt as to the validity of the reading obtained by the device in comparison to his personal estimation of the speed of the target vehicle, then he will abort the check.

OBJECTIVES FOR TRAINING
IN RESPECT OF LASER/OPTICAL DEVICE OPERATORS

The ACPO recommendations are that the duration of training should be a suitable period of time to enable an operator to qualify for the award of Certificate of Competence. At the conclusion of the course the student will:-
(a) Know the basic principles of laser/optical (whichever applicable) speed detection technology as outlined in this document and manufacturers' instructions.
(b) Be able to carry out checking, accuracy tests and operating procedures applicable to that device.
(c) Be competent in the presentation of evidence.
(d) have carried out practical operation techniques.
(e) have been fully assessed as an operator.

RED LIGHT CAMERAS

INTRODUCTION

This document has been prepared by ACPO Traffic as operational guidance which should be read in conjunction with manufacturers instructions. Where this differs or compliments the manufacturers instructions ACPO policy will take precedence.

Police forces should liase closely with highway authorities in respect of installation, the ethos being to reduce casualty figures by means of influencing driver behaviour with a view to an overall reduction of accident figures.

In this respect forces should keep in mind the considerable benefit of media involvement by advertising their commitment to such schemes both on a local and force basis.

1, CRITERIA FOR SITE SELECTION

1.1 Police forces should ensure that there is continual discussions with highway authorities in respect of the sighting and installation of permanent sites for the use of automatic devices and that they are selected in accordance with Home Office guidance to be issued.
1.2 This liaison should also extend to residents living near sites as experience has shown that the activation of the flash facility has caused annoyance particularly at night.
1.3 Whilst the installation will normally be on accident grounds police forces will be involved in the discussion process and may well be able to provide additional information from their own records, or on a basis of local experience to supplement highway authorities records. There should however be a clear indication that the accident record is significantly related to the traffic sign disobedience.

2, INSTALLATION

2.1 Roadside furniture and equipment should be installed in accordance with manufacturers instructions.
2.2 Care should be taken to ensure that the presence of the equipment does not create a road safety problem and that road signs and the like are not obscured or their effectiveness diminished by the equipment.
2.3 The use of dummy flash units should receive favourable consideration as experience has shown they have a deterrent effect and are an excellent accident prevention factor.
2.4 Experience has further shown that one camera circulating between up to a maximum of ten sites and moved at regular intervals will produce a cost effective result.

3 THE CAMERA UNIT - LOADING AND UNLOADING THE SYSTEM

3.1 These units should be tested and installed in the housing unit in accordance with individual manufacturers instructions. The parameters to which the machine has been set together with the testing procedure will be recorded at the commencement of the film and if fitted on the smart card' facility.
3.2 It is ACPO view that there is no need for a police vehicle to be used as a test facility for the device. If however in the event of a serious incident' being recorded on film forces wish to reproduce the circumstances with a view to re-enforcing certain evidence of a peripheral nature such a course of action may be of benefit.
3.3 The camera unit is fitted with a number of control switches which govern the camera operation. It is possible to regulate the camera operation in a number of fields including time delay (all manufacturers) and speed activation (Gatso only).
3.4 The speed aspect does not produce an accurate measurement for enforcement purposes. The facility however does assist in preventing numerous activations as a result of run over' and is incorporated into the Gatso device.
3.5 The time adjustment enables operators to set the device to photograph offenders contravening the red light after a specific time delay. ACPO has not suggested a minimum time setting due to the variation of circumstances at each particular site. However, forces may feel that a setting of less than half a second should not be considered. The credibility of the equipment must be maintained. Even at this setting offenders will have had three seconds of amber to stop prior to the half second.
3.6 The equipment operational time must be governed by two factors namely the length of film available for use and the volume of traffic at the site concerned. Operators should bear in mind the legal requirement for notices to be served within fourteen days of the incident.
3.7 The unit should be unloaded in accordance with manufacturers instructions ensuring that the test procedures as specified are carried out.
3.8 In the event of any fault being detected upon loading or unloading of the camera unit the fact should be reported immediately and the system taken out of use until the fault has been corrected. Likewise if when the film has been processed there is a fault or the data at the beginning and end varies the film evidence should not be used.

4 FILM PROCESSING

4.1 It is recommended that the developing of the films be undertaken by a police photo graphic unit (either force or nationally based) or alternatively a private confidential service offered nationally.
4.2 It has been identified that some police photographic units may not have the necessary equipment to process films of the lengths produced by these devices. It is therefore recommended that if this be the case that the lengths be reduced to workable units by cutting diagonally at 450, hence through a frame. (These actions will ensure that there can be no accusations of tampering with the film during the developing process).
4.3 There will be no need for forces to make prints at this early stage as viewing for prosecution purposes will be undertaken utilising the negatives.
4.4 It is the legal view, there will be no need to prove continuity in respect of these films as each will identify the site and date by means of the diode array which produces this information on each photograph. In addition the photograph will identify specific offenders through identification of the vehicle registration mark. Although this be the case forces should avoid excessive handling by numerous persons in the processing of the films.

5, VIEWING FOR PROSECUTION PURPOSES

5.1 Numerous viewing devices are available on the market however it is recommended that whatever device is utilised it should have the capability of dealing with a large reel of negatives; possess a zoom facility and be capable of reversing the film polarity as on occasions some number plates are clearer in the positive mode.
5.2 Viewers should have the Chief Constable's authority to carry out this task; prosecution decisions being made in accordance with force and national guidelines.
5.3 A close examination should be made of the film by the operator with a view to ensuring that it gives:-
a) Identical data readings at the beginning and end of the film.
b) Clear and unambiguous negatives of that alleged.
c) All the information as required by type approval is recorded.
d) Where there is a suggestion in the negative that two or more vehicles are or maybe in the measurement field, and hence cause confusion, the reading should be disregarded.

6, STORAGE OF INFORMATION

6.1 Forces and highway authorities will wish to consider the logging of information produced by such devices for statistical and easy reference purposes. This may be manual and/or computer based.
6.2 The evidence produced by these device (i.e. photographic or video) will have to be retained and stored for evidential purposes. This should be in accordance with individual force instructions and following consultation with local OPS.

PROSECUTION PROCEDURES

Specific Home Office circulars on the use of technology will be issued in due course which will deal with prosecution procedures to be followed by the police, Crown Prosecution Service and Magistrates Courts. ACPO policy in this respect already exists. However, new guide lines will have to be issued particularly in regard to the use of the conditional offer.

TYPE APPROVED TRAFFIC LIGHT CAMERAS

1 GATSOMETER BV TYPE 36
2 TRAFFIPHOT 111G RED LIGHT MONITOR

 

 

APPENDIX B

MINIMUM DISTANCES TO STOP

Speed in mph in radar display Distance travelled in 3 seconds (metres) Stopping Distances (metres) Total distance to stop at operator (metres)
30
35
40
45
50
55
60
65
70
40.2
46.9
53.6
60.3
67.0
73.7
80.4
87.1
93.8
22.8
29.3
36.5
44.5
53.3
62.8
73.1
84.2
96.0
63.0
76.2
90.1
104.8
120.3
136.5
153.5
171.3
189.8

 

(as of 1/1/93)