GB/T 21255-2019 English PDF (GBT21255-2019)

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GB/T 21255-2019: Motor vehicle speed detector
GB/T 21255-2019
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.020
R 82
Replacing GB/T 21255-2007
Motor Vehicle Speed Detector
ISSUED ON: DECEMBER 31, 2019
IMPLEMENTED ON: JULY 1, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 6 
2 Normative References ... 6 
3 Terms and Definitions ... 7 
4 Classification and Model ... 10 
5 Technical Requirements ... 11 
6 Test Methods ... 22 
7 Inspection Rules ... 39 
8 Requirements for Verification ... 42 
9 Marking, Labeling, Inspection Certificate and Packaging ... 42 
Appendix A (normative) Format of Interface ... 44 
Appendix B (normative) Information Items of Point-to-point Speed Detector . 52 
Appendix C (normative) Information of Running Status ... 56 
Bibliography ... 57 
Motor Vehicle Speed Detector
1 Scope
This Standard specifies the classification, technical requirements, test methods,
inspection rules, verification requirements, and the technical requirements for marking,
labeling and packaging of motor vehicle speed detector.
This Standard is applicable to devices for the speed measurement of motor vehicles
on the road.
2 Normative References
The following documents are indispensable to the application of this document. In
terms of references with a specified date, only versions with a specified date are
applicable to this document. In terms of references without a specified date, the latest
version (including all the modifications) is applicable to this document.
GB/T 2423.1 Environmental Testing for Electric and Electronic Products - Part 2: Test
Methods - Tests A: Cold
GB/T 2423.2 Environmental Testing for Electric and Electronic Products - Part 2: Test
Methods - Tests B: Dry Heat
GB/T 2423.3 Environmental Testing - Part 2: Test Method - Test Cab: Damp Heat,
Steady State
GB/T 2423.5 Environmental Testing for Electric and Electronic Products - Part 2: Test
Methods - Test Ea and Guidance: Shock
GB/T 2423.10 Environmental Testing for Electric and Electronic Products - Part 2: Test
Methods - Test Fc: Vibration (sinusoidal)
GB/T 2423.17 Environmental Testing for Electric and Electronic Products - Part 2: Test
Methods - Test Ka: Salt Mist
GB/T 4208 Degrees of Protection Provided by Enclosure (IP code)
GB 7247.1-2012 Safety of Laser Products - Part 1: Equipment Classification and
Requirements
GB/T 17626.2 Electromagnetic Compatibility - Testing and Measurement Techniques
- Electrostatic Discharge Immunity Test
GB/T 17626.3 Electromagnetic Compatibility - Testing and Measurement Techniques
- Radiated, Radio-frequency, Electromagnetic Field Immunity Test
GB/T 17626.4 Electromagnetic Compatibility - Testing and Measurement Techniques
- Electrical Fast Transient / Burst Immunity Test
GB/T 17626.5 Electromagnetic Compatibility - Testing and Measurement Techniques
- Surge Immunity Test
GB/T 17626.11 Electromagnetic Compatibility - Testing and Measurement Techniques
- Voltage Dips, Short Interruptions and Voltage Variations Immunity Tests
GB/T 19056 Vehicle Travelling Data Recorder
GB/T 21437.2 Radio Vehicles - Electrical Disturbances from Conduction and Coupling
- Part 2: Electrical Transient Conduction along Supply Lines Only
GA/T 16 (all parts) Code for Management Information of Road Traffic
GA 36 License Plate of Motor Vehicle of the People’s Republic of China
GA/T 497 General Technical Specifications for Intelligent Monitoring and Recording
System for Vehicles on Roads
GA/T 543 (all parts) The Data Elements for Public Security
GA/T 832 Technical Specifications for Image Forensics of Road Traffic Offences
GA/T 833 Technical Specifications for Automatic Recognition Technology of Motor
Vehicle License Plate Images
GA/T 1043 Specifications for Operation and Maintenance of Road Traffic Monitoring
and Controlling Equipment
GA/T 1202 General Technical Specifications for Fill Light Devices of Traffic Monitoring
Cameras
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 Motor Vehicle Speed Detector
Motor vehicle speed detector is a device for the speed measurement of a motor vehicle
running on the road.
3.2 Radar Speed Detection
Radar speed detection is a method of calculating the running speed of a motor vehicle
Speed detection in moving mode is a method of measuring the running speed of a
motor vehicle when the vehicle is in moving mode and the speed detector is installed
on the vehicle being tested.
3.11 Speed Detection Angle
Speed detection angle is the angle between the speed detection unit of the speed
detector and the running direction of the motor vehicle being tested.
3.12 Detection Area
Detection area refers to the area where the speed detector can effectively measure
the running speed of the motor vehicle and collect images of the corresponding motor
vehicle.
3.13 Speed Detection Range
Speed detection range refers to the range, within which, the speed detector can
effectively measure the running speed of a motor vehicle.
3.14 Effective Area of Taking Pictures
Effective area of taking pictures refers to the area where the speed detector can clearly
capture images of a motor vehicle.
3.15 Overspeed Vehicle Capture Ratio
Overspeed vehicle capture ratio refers to the percentage of the number of effectively
recorded overspeed vehicles to the number of effectively passing overspeed vehicles.
NOTE 1: the number of effectively recorded overspeed vehicles refers to the number of
vehicles that contain effective vehicle information (license plate number, license
plate color and vehicle type, etc.) and corresponding running speed in the record.
NOTE 2: the number of effectively passing overspeed vehicles refers to the number of
vehicles that exceed the speed limit in the actual driving and have an intact
license plate (the hanging of the license plate is standardized; there are no
obstructions or defects).
3.16 Effective Ratio of Overspeed Vehicle Images
Effective ratio of overspeed vehicle images refers to the percentage of the number of
effectively recorded images of overspeed vehicles to the total number of recorded
images.
NOTE 1: among the number of effectively recorded images of speeding vehicles, the
number of valid recorded images of the same speeding vehicle is no more than
3.
± 10%)  nom.
NOTE: nom is the nominal value of main lobe width of transmitting antenna of the multi-
target radar speed detector, expressed in (°).
5.3.2.2.2 Sidelobe level
The sidelobe level of the multi-target radar speed detection unit shall be less than -15
dB.
5.3.2.2.3 Average value of microwave emission frequency
The average value of microwave emission frequency of the multi-target speed
detection unit shall comply with (1 ± 0.2%)  f0.
NOTE: f0 is the nominal value of microwave emission frequency of the multi-target
radar speed detector, expressed in (MHz).
5.3.3 Laser speed detection unit
5.3.3.1 Pulse repetition rate
The pulse repetition rate of the laser speed detection unit shall be not greater than
0.1%.
5.3.3.2 Eye safety
The laser speed detection unit shall comply with the Class-1 safety requirements for
human eyes in GB 7247.1-2012.
5.3.4 Loop speed detection unit
5.3.4.1 Self-check function
The loop speed detection unit shall be able to automa...