Road scanners

Inclement and variable weather can make for treacherous conditions on the road, but solutions are available to aid traffic managers with such challenges

Words | Anders Björk, MetSense, Sweden

Higher demands for road weather monitoring and maintenance are being imposed, as a result of increasing traffic volumes and requirements for emergency prevention. Technological developments aim to find an elaborate solution that makes road monitoring more cost-effective and eco-friendly, and can increase traffic safety.

Two key types of sensors have been developed to monitor road weather conditions: intrusive sensors that require physical installation into the road surface, and non-intrusive sensors that operate remotely without causing any damage. Both types of sensors have limitations, however.

Non-intrusive monitoring

A new meteorological video camera, 2DRoad, developed by MetSense, has a unique non-intrusive sensor that provides a full multilane description of road friction and road surface conditions. In contrast to most widely used devices, the sensor can scan a broad road area instead of one particular point and it does not need to be physically installed in the surface of a road.

In a fast, easy process, the modern 2DRoad meteorological camera can take a number of near-infrared spectroscopy pictures, and an invisible flash can adjust light conditions in the area. Each picture is filtered to capture only part of the spectrum, and detection of the current state of the road is based on an analysis of the images. This

Left: The 2DRoad

meteorological camera

Below: The visual

output from a meteorological camera

complete process can be carried out from a remote location, so no adjustments to the road surface are required.

The 2DRoad sensor can provide information about a road surface area of 2m2 (21.5ft2) to 6m2 (64.6ft2). This area is divided into 64x64 points – 4,096 in total. The sensors of other non-intrusive devices can monitor only one point or just a few square centimeters. The area covered by 2DRoad can be set according to the requirements of the road. Subsequent outcomes can then provide an overview of the whole area selected.

For each point, the camera can determine whether the road surface is dry, wet or covered in snow or ice. This is calculated according to different wavelengths that correspond to a particular type of surface and its condition. The camera recognizes seven road surface statuses: dry, moist, wet, dark ice, bright ice, snow and slush. Using an integrated pyrometer, the 2DRoad platform can also remotely measure the road surface around the center of a point.

The outcome of a meteorological road scan is organized and structured into a simple, visual and data-based presentation with a clear view of the state of the road at each point that is monitored. These data presentations are particularly useful for winter road maintenance contract dispatchers and for other road maintenance workers.

Implementing sophisticated meteorological information systems with well-equipped sensors, such as 2DRoad, is key for reducing maintenance costs, making winter road maintenance more efficient, increasing road safety and being kind to the environment.

An eco-friendly solution

Adverse weather conditions, whether snow, heavy rain or dry, can greatly influence the cost of road maintenance and affect overall safety. The potential outcomes caused by these elements can be reduced with the use of proper and up-to-date meteorological information systems. With adequate measures and suitable devices in place – for example, detailed weather forecasts – maintenance can be targeted at specific parts of the road. Prompt and efficient treatment of roads can lead to increased safety for road users.

Subsequent maintenance can be directed exactly to the area of road that is affected by natural, weather-related events and this in turn reduces the need for, and amount of, human resources required.

Another advantage of sophisticated meteorological information systems is that they are eco-friendly. With efficient road area targeting, which reduces the need for excessive and unnecessary interventions, a smaller amount of chemicals (such as road salt and brine) is needed to treat roads. n