There are Four main speed cameras utilised to detect a speeding motorist.
Briefly they are:-
Gatso fixed cameras uses radar technology at the passing vehicle. The beam is then returned back to the speed camera equipment, providing an exact speed. These cameras usually take rear shot of the vehicle
LTI 20/20 are the favoured camera of the mobile units. They can be hand held but are usually stand mounted. Usually they take a front shot when tripod mounted but can be reversed to take a rear view shot.
- Truvelo use loops in the road, if the passing vehicle drives too fast over the loops, the speed camera is triggered. These can take a front shot.
- Specstake a photograph of all passing vehicles at point 'a', then several hundred metres along the road at point 'b' a second photograph is taken. Both photographs are date and time stamped, the speed camera equipment then calculates your average speed. Specs Presentation click here
Truvelo Gatso LTI20/20 Specs
More information can found by clicking on the respective camera. There are other derivaties of the above and other models but basically they are all designed to give an accurate calculation on the speed of a vehicle.
How they work Mobile CamerasPhotographic Evidence
In the case of mobile enforcement, the officer assesses the speed of the vehicle as being in excess of the speed limit for the road and uses the equipment to corroborate this by taking a single photograph. At the same time a video is recorded which acts as an audit trail. The details on the photograph show the date, time, site code, officer details, speed and direction of travel.
Calibration All equipment is calibrated annually in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Camera officel for that area.
PersonnelThe cameras are managed on a daily basis by the Camera Technicians under the supervision of the Senior Camera Technician. All staff are trained and certified in accordance with Home Office and Department of Transport Guidelines. Training certificates for all staff are held at the Central Ticket Offices, and are the responsibility of the Senior Camera Technician. In addition to this, all technicians are assessed every three months by the Senior Camera Technician.
The system consists of a camera and a flash unit that are linked to speed radar. The activation occurs when a vehicle exceeds the predetermined speed that is set on the unit.
Photographic EvidenceIn the case of static or fixed sites, two photographs are taken by the apparatus, each being 0.5 seconds apart. As the time between the two photographs is known, the distance the vehicle has travelled can be measured and the speed is determined.
This distance is measured by counting the number of marks that are painted on the road surface. The distance between the marks is exact and is checked on an annual basis along with the rest of the site.
CertificationAll sites are commissioned and certified in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices, and are the responsibility of the Camera Technicians and the local road safety partnerships.
Prior to each site being used the Camera Technician carries out a visual inspection to ensure nothing is amiss. Records of all these checks are logged in the technicians notebook. In the event that a site is at fault then it is not used until the fault has been rectified to the satisfaction of the Senior Camera Technician.
CalibrationAll equipment is calibrated annually in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices,
Enforcement Speeds
Below is a table that it is representative only. It is important to realise that different police areas will have different cautioning and conditional offer levels. Some forces also run Speed Awareness Courses (SAC) as a diversion from prosecution. At the moment these are few and far between but we expect the numbers to grow in the future.
The ACPO guidelines are clear on two things .
- That enforcement should begin following the ten percent plus two mph rule Eg 50 mph + 10% (5) + m2 mph = 57.
- Thata driver cannot be dealt with a Conditional Offer of Fixed Penalty if the speeds reach the levels indicated in the last column
Speed limit
Enforcement speed
Caution
S.A.C
Con Offer
Summons
30
35
35
36
37
50
40
46
46
47
48
66
50
57
57
58
59
76
60
68
0
0
68
86
70
79
0
0
79
96
All equipment is calibrated annually in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Camera officel for that area.
PersonnelThe cameras are managed on a daily basis by the Camera Technicians under the supervision of the Senior Camera Technician. All staff are trained and certified in accordance with Home Office and Department of Transport Guidelines. Training certificates for all staff are held at the Central Ticket Offices, and are the responsibility of the Senior Camera Technician. In addition to this, all technicians are assessed every three months by the Senior Camera Technician.
The system consists of a camera and a flash unit that are linked to speed radar. The activation occurs when a vehicle exceeds the predetermined speed that is set on the unit.
Photographic EvidenceIn the case of static or fixed sites, two photographs are taken by the apparatus, each being 0.5 seconds apart. As the time between the two photographs is known, the distance the vehicle has travelled can be measured and the speed is determined.
This distance is measured by counting the number of marks that are painted on the road surface. The distance between the marks is exact and is checked on an annual basis along with the rest of the site.
CertificationAll sites are commissioned and certified in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices, and are the responsibility of the Camera Technicians and the local road safety partnerships.
Prior to each site being used the Camera Technician carries out a visual inspection to ensure nothing is amiss. Records of all these checks are logged in the technicians notebook. In the event that a site is at fault then it is not used until the fault has been rectified to the satisfaction of the Senior Camera Technician.
CalibrationAll equipment is calibrated annually in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices,
Enforcement Speeds
Below is a table that it is representative only. It is important to realise that different police areas will have different cautioning and conditional offer levels. Some forces also run Speed Awareness Courses (SAC) as a diversion from prosecution. At the moment these are few and far between but we expect the numbers to grow in the future.
The ACPO guidelines are clear on two things .
- That enforcement should begin following the ten percent plus two mph rule Eg 50 mph + 10% (5) + m2 mph = 57.
- Thata driver cannot be dealt with a Conditional Offer of Fixed Penalty if the speeds reach the levels indicated in the last column
Speed limit
Enforcement speed
Caution
S.A.C
Con Offer
Summons
30
35
35
36
37
50
40
46
46
47
48
66
50
57
57
58
59
76
60
68
0
0
68
86
70
79
0
0
79
96
In the case of static or fixed sites, two photographs are taken by the apparatus, each being 0.5 seconds apart. As the time between the two photographs is known, the distance the vehicle has travelled can be measured and the speed is determined.
This distance is measured by counting the number of marks that are painted on the road surface. The distance between the marks is exact and is checked on an annual basis along with the rest of the site.
CertificationAll sites are commissioned and certified in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices, and are the responsibility of the Camera Technicians and the local road safety partnerships.
Prior to each site being used the Camera Technician carries out a visual inspection to ensure nothing is amiss. Records of all these checks are logged in the technicians notebook. In the event that a site is at fault then it is not used until the fault has been rectified to the satisfaction of the Senior Camera Technician.
CalibrationAll equipment is calibrated annually in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices,
Enforcement Speeds
Below is a table that it is representative only. It is important to realise that different police areas will have different cautioning and conditional offer levels. Some forces also run Speed Awareness Courses (SAC) as a diversion from prosecution. At the moment these are few and far between but we expect the numbers to grow in the future.
The ACPO guidelines are clear on two things .
- That enforcement should begin following the ten percent plus two mph rule Eg 50 mph + 10% (5) + m2 mph = 57.
- Thata driver cannot be dealt with a Conditional Offer of Fixed Penalty if the speeds reach the levels indicated in the last column
Speed limit
Enforcement speed
Caution
S.A.C
Con Offer
Summons
30
35
35
36
37
50
40
46
46
47
48
66
50
57
57
58
59
76
60
68
0
0
68
86
70
79
0
0
79
96
All equipment is calibrated annually in accordance with Home Office and Department of Transport Guidelines. Certification certificates for all sites are held at the Central Ticket Offices,
Enforcement Speeds
Below is a table that it is representative only. It is important to realise that different police areas will have different cautioning and conditional offer levels. Some forces also run Speed Awareness Courses (SAC) as a diversion from prosecution. At the moment these are few and far between but we expect the numbers to grow in the future.
The ACPO guidelines are clear on two things .
- That enforcement should begin following the ten percent plus two mph rule Eg 50 mph + 10% (5) + m2 mph = 57.
- Thata driver cannot be dealt with a Conditional Offer of Fixed Penalty if the speeds reach the levels indicated in the last column
Speed limit | Enforcement speed | Caution | S.A.C | Con Offer | Summons |
30 | 35 | 35 | 36 | 37 | 50 |
40 | 46 | 46 | 47 | 48 | 66 |
50 | 57 | 57 | 58 | 59 | 76 |
60 | 68 | 0 | 0 | 68 | 86 |
70 | 79 | 0 | 0 | 79 | 96 |
Speed Calculation-Fixed Camera
This photograph is the first of two taken by the GATSO fixed camera at a time interval of 0.5 seconds
There is a block of data on the top right hand corner of the photograph and contains the following information:
1. the last three digits n the first line show the speed of the vehicle; 84 mph
2. The second ine shows, ffrom left to right, the time of the offence (six digits) and the date of the offence (six digits).
3. The third line shows the site number (three digits) and the fim negative number (three digits)
Second Photograph
This is the second photograp taken by the GATSO camera, the date block contains the following information;
1. The first line identifies the type of device;
2. the second line shows the time and date;
3. The third line confirms that the photograph was taken 0.5 seconds after the first and gives the filme negative number (three digits).
By using he secondary check marks on the carriageway, the approximate speed of the vehicle can be calculated.
Calculation
First count the number of lines the vehicle has travelled in the time between the first and second frames (0.5 seconds). the distance between each line is 5 feet.
Number of lines travelled 12.1
Multiply by the distance beteen each line 5.
The result is multiplied by 2 to give the speed of the vehicle per second= 123
To convert this to mph = 123 (feet per second) multiplied by 3600 (seconds per hour) divided by 5280 (feet per mile) = 83.86mph
Speed Calculation - Mobile Cameras
The camera utilises an infrared beam calibrated to 999metres
The beam is positioned on the vehicle where the cross-hairs (see below) converge. The beam is a relatively narrow and at about 400 metres it is only the circle radius of the number plate. At a distance of about 200 metres it narrows further to the size of a tennis ball.
As can be seen the reading is instant at 42 mph.
The second shot below of the same vehicle (Note the driver can be identified)
Accuracy
There is hot debate on the question of camera reliability and accuracy. To put this into perspective the Gatso technology is now comparativley old but its still reliable in its accuracy. The newer laser based technologies have come under more scrutiny with submissions being made that the beam has been deflected off the road or some other static structure, prior to hitting vehicle being checked. This alleged fault is termed "slippage" and at least one expert in laser technology is convinced the LTI 20/20 is flawed (especially the ultralyte model). The Daily Mail of 15/10/05 ran a comprehensive article on the subject and is worth a read. The problem is that the Home Office experts are equally convinced of its reliability, so its a case of watch this space for the foreseeable future.
If this line of defence is taken be prepared for a long battle with the big guns at CPS. A better option is to request the video to peruse at an early stage and state why you require it. It may just be enough to stay a prosecution. However the legislation regarding its disclosure is set against the motorist until the motorist has entered a firm Not guilty plea-more about this on the advice page
The cameras can only take readings from moving objects so taking this type of defence line is risky to say the least and definitley in the realm of the expert
Calibration (Checking the equipment)
All speed cameras have to calibrated on arealy basis as a minimum and checks are taken on a daily basis for some camera types. Speedometers on police vehicles must be approved at point of installation and should be calibrated ( checked) on daily basis and must be calibrated after a detected speed offence