Mobile mapping technology of wind velocity data along highway for traffic safety evaluation

Traffic safety of highway vehicles under strong crosswind gust and other hazardous driving conditions has become a pressing issue for modern highway transportation and economy. It is known that the actual wind environment at the typical height of a moving vehicle varies considerably from one segment to another even on the same highway, because of influence of the specific terrain and surroundings. Therefore, accurate crosswind velocity data in both time and spatial domains are needed, for a rational assessment of traffic safety risks for various moving vehicles on highways in windy conditions. In addition to site-specific wind data which can be used for most vehicles, vehicle-specific crosswind velocity is often required for an accurate safety assessment of high-sided vehicles with unique shapes. A mobile mapping technology aiming at collecting site-specific as well as vehicle-specific wind velocity data for traffic safety evaluations was developed. Such technology integrates a 3D sonic anemometer and geospatial video mapping system, mounted on a vehicle driven along highways at a normal (cruising) speed. As a result, both vehicle-specific and general site-specific crosswind velocity can be directly “sensed” and collected by using a high-sided vehicle or a streamlined car as the test vehicle. A field test of the developed technology with a high-sided truck driven on mountainous sections of the interstate I-70 (in Colorado) was conducted. The crosswind data at six selected feature locations along I-70, representing different roadside environments, was analyzed. Wind-tunnel investigations employing the scaled models of the truck used in the field test as well as a common streamlined sedan car were conducted to evaluate the accuracy and the feasibility of the developed technology.