At present, the speed measurement methods commonly used in my country include radar speed measurement, ground sensor coil speed measurement, video speed measurement, infrared detection and laser speed measurement. Among them, radar speed meter is the most widely used in my country's public security traffic management department because of its low price, easy use and ability to detect vehicle speed during movement. The editor focuses on the application of laser speed measurement in road traffic law enforcement.
1. The principle of laser speed measurement
Laser speed measurement is a vehicle speed detection technology developed in foreign countries in the 1990s. It adopts the principle of laser ranging (i.e. electromagnetic wave, with a speed of 300,000 kilometers per second). By emitting a laser beam to the object to be measured, receiving the reflected wave of the laser beam, and recording the time difference, the distance between the object to be measured and the test point is determined. Laser speed measurement is to perform laser ranging on the object to be measured twice with a specific time interval, obtain the moving distance of the object to be measured during the period, and thus obtain the moving speed of the object to be measured.
2. Characteristics of laser speed measurement
1. Accurate aiming: The laser beam emitted by the laser speed meter is extremely fine (the divergence angle of the laser emission part is 3mrad), and the diameter is only 30cm at 100 meters, so the irradiation surface is small and can accurately aim at any target.
2. Long measurement range: The speed measurement distance is far from the effective distance of radar speed measurement, and can measure 1000M away. It can be captured from a long distance without being detected.
3. Sensitive speed measurement: fast response, single speed measurement time is about 0.33-0.66 seconds.
4. Static use: In view of the principle of laser speed measurement, the laser speed meter cannot be used in motion, but can only be used in a static state; therefore, traffic police generally put the instrument on the patrol car and use it when it is parked.
5. Anti-interference: Since the laser beam of the laser speed meter is extremely thin and its response time is extremely fast, the general electronic detectors on the market are useless for interfering with and detecting the laser speed meter.
III. Application of laser speed measurement in traffic law enforcement
At present, many law enforcement units in China are using handheld laser speed meters LTI TruSpeed, Onick LS320, and LSP320 with photo evidence speed meters. The laser speed meter is a new type of traffic management law enforcement tool. It provides a reliable technical evidence collection method for the governance of illegal speeding. It overcomes the shortcomings of radar speed meters such as slow measurement speed, wide beam, and adverse effects of radiation on human health. Therefore, it has advantages that radar speed meters cannot match. It can measure speed and distance, and has strong functionality. It can effortlessly detect the speed of a single vehicle or even a motorcycle on a busy multi-lane road. With the widespread use of new equipment, radar detectors alone can no longer provide sufficient protection. It can be seen that laser speed measurement will be more and more widely used in future traffic law enforcement.
