The road condition sensor avoids damage to the road surface, thereby avoiding the interference to traffic caused by the installation of road weather stations in the past. Remote sensing installation means no need to cut the road surface or break the circuit. The principle of spectral measurement enables accurate measurement of the amount of water, ice, and snow. The road condition sensor also provides measurement of the degree of wetness. Next, let me introduce the working principle of road sensors!

The road condition sensor is used to indicate the degree of slippery road surface caused by icing. The road condition sensor is based on spectrum for close range telemetry of the road surface. The road condition sensor is equipped with an infrared emitter aimed at a selected position on the road surface, and the emitted light is reflected from the measured location into the receiver for integration. Sensors can distinguish specific wavelength reflections caused by water or ice on road surfaces, and can also detect snow or frost. Usually, when the ice layer reaches about 30 μ m, the road surface begins to become slippery. The high sensitivity of the road condition sensor makes it easy to detect ice of this magnitude. However, the smoothness of the pavement is not only related to the amount of ice. Research has shown that hard ice roads with low moisture content are smoother than soft ice with a large amount of water or salt.

The road condition sensor can detect water and ice separately, thus establishing a practical "slippery degree" index that represents the friction ability of typical road surfaces and tires. On dry roads, this index is set to nearly 0.8, while on hard ice roads or roads with a lot of snow, this index decreases to 0.1. The level of this index is based on the measurement of actual friction force under various road meteorological conditions.

The road condition sensor can be installed on the roadside, facing the road surface at a horizontal angle greater than or equal to 30 degrees. It can also be installed above roads, such as bridges or signal lights. The traffic flow at the measured location will not affect the measurement unless there are vehicles completely parked at the measured location for several minutes. The road condition sensor is a processor based system that can be used as a component of the road weather station network.

The remote sensing road condition sensor adopts infrared laser remote sensing technology, which does not require cutting the road surface and avoids damage to the road. Non contact remote sensing detection means that there is no need to close the road, and the installation work is both safe and convenient. It is an ideal choice for road meteorological monitoring systems as it will not cause interference to traffic due to the installation of detectors. It can be installed on existing weather stations or on other buildings with unobstructed road views. The telemetry based road surface condition sensor compares the spectral information reflected by dry road surfaces with the spectral information obtained under covered conditions based on the infrared spectral characteristics of water, ice, and snow. It detects the dry, wet, and damp states of the road surface in real time, measures the coverage type and thickness of water, ice, and snow, and provides road slippery warning information for the road meteorological information system. At the same time, it has infrared temperature measurement function, can monitor road surface temperature, and provide high temperature warning. The instrument is installed in an all-weather, durable casing to withstand harsh weather conditions, allowing it to provide accurate data under any weather conditions.