Road condition monitoring

Common measurement principles involve in situ measurements, where sensors are embedded in the road surface, and remote sensing technologies using visual cameras and infrared (IR) sensors or cameras. Recent days, development of cooperative traffic systems has increased the expectations concerning automatic road friction measurement units. Automotive industry has been investigating chances to utilize the roadside friction data for adjusting car control functions (i.e., ADAS). This chapter will review the promising camera vision and the short-wave IR (SWIR) laser unit technology to provide friction estimation for road users. The laser system consists of two laser diodes emitting at wavelengths λ1 = 1323 nm and λ2 = 1566 nm, whereas the camera system operates in the near-IR (NIR) band 850–950 nm. The algorithms have been developed to identify condition of the road surface (dry, wet, snow, icy, etc.