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Groundbreaking road sensors

Vaisala offers a modular, highly configurable range of options for collecting, managing, and displaying actual and forecast weather data for roads and airport runways. Chicago is one of the cities to have opted for Vaisala technology to help improve both reactive maintenance and proactive operations in advance of bad weather.

Chicago is well-known for its changeable weather, and receives an average of 39 inches (99 cm) of snow every winter. The city’s Snow Command Center, managed by the Department of Streets and Sanitation, is responsible for keeping the streets free of ice and snow, and dispatches a fleet of salt spreaders/ploughs to 261 major routes when bad weather nears the city.

Traditionally, the city relied on pavement weather data from a network of embedded sensors at various key locations to provide the information needed for this, but these proved expensive to install and maintain. A non-intrusive pavement sensor package from Vaisala has proved a major step up in performance and reliability.

Thanks to Vaisala technology, Chicago is now better-prepared to deal with its tough winter weather. Photo courtesy of the City of Chicago.

Quick installation, low costs

Vaisala’s road weather sensors now play an important part in the resources available to Chicago’s state-of-the-art Snow Command Center, together with cameras, radar, and Global Positioning Satellite (GPS) sensors.

The sensors have been deployed at key locations, mainly on bridge decks, which have a tendency to freeze well before surrounding roads. By utilising existing light columns, it was possible to install them in under four hours, a fraction of the time needed for traditional sensors, and at a fraction of the cost as well.

How slippery are the roads?

The spectroscopic measuring principle employed by the Vaisala Remote Road Surface State Sensor DSC111 delivers a substantial improvement on the type of data previously gleaned from Road Weather Information Systems (RWIS). Because the sensor measures water, black ice, and white ice (hoar frost) independently of each other, it is now possible to track the reduction in surface friction resulting from adverse weather. This means that maintenance personnel can now determine how slippery a road surface is, as well as measure its temperature and state, and provide objective performance indicators.

Non-intrusive sensor solutions such as the one in Chicago are revolutionising the traditional concept of road weather information and opening up cost-effective solutions for cities, large and small, and bypassing the disruption and cost traditionally associated with obtaining critical information of this type.

The Vaisala Remote Road Surface State Sensor DSC111 enables highway engineers to determine how slippery road surfaces are, as well as roadside temperatures and overall conditions. By utilising existing light columns, Chicago was able to install its sensors in a fraction of the time needed for traditional sensors, and at a fraction of the cost.

Traffic management solutions

Vaisala provides a comprehensive range of applications for road engineers to deal with adverse weather events, such as ice, snow, and fog, all of which can have a major impact on traffic flows and safety through accidents and delays.

The company’s roadside weather stations – also known as RWIS or Environmental Sensor Sites (ESS) – provide real-time data, while short-term SnowCasts, 24-hour forecasts, and Thermal Mapping ensure that engineers have all the decision-making tools they need to manage situations. Provided as complete solutions with 24-hour support and maintenance, data quality control, and ‘Best Practice’ consultancy, Vaisala’s solutions can make a real difference.


Vaisala is a global leader in environmental and industrial measurement. Building on over 70 years of experience, Vaisala contributes to better quality of life by providing a comprehensive range of innovative observation and measurement products and services for meteorology, weather-critical operations, and controlled environments.

Headquartered in Finland, Vaisala employs over 1,100 professionals and has customers in over 100 countries.

> Paul Bridge
(Published in HighTech Finland 2009)