Visibility Sensors Enhance Expressway Weather Monitoring and Safe Travel

Visibility sensors are professional meteorological monitoring devices designed for expressway environments. Operating within a network of roadside stations, they capture real-time data on road visibility and weather phenomena, transmitting this information to monitoring platforms to assist with traffic management. They also support the expansion and upgrading of various other meteorological monitoring systems.

As a core component of road weather monitoring systems, these sensors are primarily deployed along expressways. Through a networked multi-station configuration, they enable automated, continuous monitoring of regional weather conditions. The device comprises an optical transmitter, an optical receiver, and a microprocessor controller, utilizing the principle of aerosol forward scattering for detection. The transmitter emits infrared pulsed light, while the receiver captures the intensity of light scattered by atmospheric aerosol particles. Built-in algorithms then precisely calculate the meteorological optical range, ensuring professional-grade accuracy in the monitoring data.

These visibility sensors offer robust monitoring capabilities, featuring a standard measurement range of up to 50 km and a resolution of 1 meter. Measurement errors are tightly controlled based on the range: under 2% for distances up to 2 km, under 5% for the 2–10 km range, and under 10% for distances exceeding 10 km, with a repeatability error of less than 4%. Additionally, the devices accurately identify various weather phenomena—such as fog, rain, snow, and mixed precipitation—with a recognition rate of at least 95%, effectively capturing adverse weather conditions that impact expressway traffic.

Designed for complex outdoor road environments, the sensors are equipped with 4G wireless transmission modules that rapidly upload real-time monitoring data to cloud platforms and traffic monitoring systems, enabling immediate data sharing. They support dual power supply modes—solar and mains power—allowing for flexible selection based on local infrastructure, which significantly enhances operational stability and adaptability. The complete monitoring system includes the visibility sensor, data logger, mounting pole/bracket, power supply system, and cloud platform, offering a streamlined structure and ease of operation and maintenance. To meet monitoring requirements across different road sections, the visibility sensor can be equipped—as needed—with devices such as an integrated weather station (measuring temperature, humidity, wind, pressure, and rainfall) and a laser-based road surface condition sensor, thereby expanding capabilities for monitoring meteorological elements and road surface conditions. During adverse weather—such as rain, snow, or dense fog—the system promptly issues early warnings to both traffic management personnel and passing drivers, facilitating traffic control operations, effectively mitigating risks associated with poor weather, and continuously enhancing the safety and orderly operation of highway traffic.