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back to Services & Technology list  Weather Applications > Weather Information
When road users are better informed about road weather conditions, they can respond accordingly by changing their travel routes, slowing down, or staying home. It is also important that highway agency and public safety personnel have accurate and timely information about weather conditions. In recent years, a number of different systems have been developed to disseminate the data that is increasingly gathered by automated or intelligent systems. Some of the most widely used systems are remotely and automatically updated dynamic (or changeable) message signs, the 511 telephone number, highway advisory radio, advanced traveler information services, and various Internet and cell phone services. There are various types of systems to disseminate weather-related traveler information. While many are specific to particular states, the most widely used are what are known as road weather information systems. Sensors collect real-time data on air and pavement temperatures, precipitation, and other factors, such as the amount of deicing chemicals on the pavement. These data are combined with information from meteorological services to predict pavement temperatures for a specific area, such as a mountain pass, over a 24-hour period. The predictions are then transmitted to a computer at the highway agency's winter maintenance center. Because deicing chemicals must be applied about an hour before pavement reaches freezing temperatures, this information is critical to an anti-icing strategy. (See "Snow and Ice Removal") Using portable computers linked by modem to the central computer, maintenance managers can monitor conditions, advise motorists, and dispatch crews as necessary. Washington State Road Weather Information System In 2002 the Washington State Department of Transportation (WSDOT) integrated two environmental sensing stations (which included closed-circuit tv cameras enabled for live broadcast in real time) with a road weather information system and transportation management center on a remote stretch of U.S. 395 north of Spokane. The information collected by the environmental sensor stations and cameras was disseminated to travelers via the WSDOT traveler information Web site. Forty drivers for trucking companies were polled before and after the new information system was installed, and majority (57%) said they felt safer having the additional information. To learn more, go to http://www.benefitcost.its.dot.gov/ITS/benecost.nsf/ByLink/BOTM-February2005 In 1999 the Washington State Department of Transportation (WSDOT) developed rWeather, a real-time statewide system that collects and disseminates road and weather information via a Web site. It provides access to more than 400 observing locations around the state, area forecasts, and road information such as closures or construction. The site was updated in 2003 and 2004 with enhanced road weather information display capabilities that provide visual clues to current weather and pavement temperatures over certain road segments. It also provides near real-time camera views of key stretches of highway, including mountain passes and border crossings, as well as access to statewide weather reports and road conditions. The site is located at http://www.wsdot.wa.gov/traffic/. For a WSDOT report on rWeather go to http://www.wsdot.wa.gov/biz/atb/pdfs/rWeather_fall2004.pdf Automated Real-Time Road Weather System (ARROWS) In 2003 the Washington State Department of Transportation launched ARROWs, which provides forecasts of weather and pavement conditions for the state’s entire network of highways. Accurate and timely weather and road condition forecasts are crucial for selecting the right strategy for tackling snow and ice, but most meteorological services are site-specific and cannot provide pavement-specific information. ARROWS, which was developed by the University of Washington for use by highway maintenance personnel around the state, takes numerical weather prediction output and presents roadway forecast information in an easy to use format. Integrating weather information sources into a high-resolution modeled output, ARROWS provides forecasts of key information milepost by milepost. For more on ARROWS, go to http://www.wsdot.wa.gov/biz/atb/pdfs/rWeather_fall2004.pdf This three-digit telephone number designated by the Federal Communications Commission in July 2000 connects callers to traffic, weather and road condition information. There are currently 25 5-1-1 systems across the country in 21 states. Eventually travelers will be able to dial 511 anywhere in the country to obtain local travel information. 511 services are developed by state and local transportation agencies with help from the private sector. In general, each system relies on information already collected for managing traffic and transit, including weather information, and makes it available in real time to callers around the clock. In areas where 511 has been implemented, travelers have responded enthusiastically. In Virginia, nearly half of callers adjusted their travel plans based on information received via 511. Weather information considered to be most valuable to travelers is atmospheric weather, such as precipitation and winds, road weather, such as pavement temperatures, fog at the road surface, and road conditions, such as icy roads or roads that have been plowed or treated with salt. (Source: 511 Deployment Assistance Report #6, June 2003) How Are Weather-Related Traveler Information Dissemination Systems Integrated with Other ITS Weather Systems? Most traveler information systems are integrated with other ITS weather systems in order to increase their efficiency. Here are examples of programs that illustrate these various combinations: Traveler information systems that also detect weather: The FHWA’s Highway Fog Warning System detects fog conditions with visibility sensors and conveys that information to drivers through roadside displays or audio communication. Traveler information systems that also forecast weather: The 5-1-1 systems are designed to forecast weather conditions and provide travelers with road condition reports via cellular or wireless phones. Traveler information systems that can detect and forecast weather: Aurora research programs study the different aspects of RWIS, including ways of improving its forecasting and information dissemination capabilities. Go to Aurora Web site. Traveler information systems that can detect weather, forecast weather, and initiate road maintenance: Anti-icing and de-icing technologies are often used in conjunction with RWIS, resulting in an integrated system that can forecast and monitor weather, maintain roads, and disseminate road weather information to travelers. Traveler information systems that can detect weather, forecast weather, and control traffic in adverse weather conditions: The Tennessee Fog Detection and Warning System detects foggy conditions, predicts fog formation, and disseminates this information to travelers. It also controls traffic speed through variable speed limit signs. Highway officials can make more informed choices about how to manage road networks in adverse weather conditions (i.e., how and when to deploy highway maintenance vehicles to treat roads affected by precipitation). Road users can know about upcoming weather conditions and adjust their travel time, mode of transportation, or even delay their trip. Implementation and Operational Challenges User satisfaction with 511 services has been extremely high, and use has risen dramatically, although it is still available in limited areas of the country. Nationwide RWIS need to be expandable, transferable, and compatible. The lack of a standardized architecture hinders the spread of RWIS. Many road maintenance staff are resistant to RWIS because they are uncomfortable with the new technologies and lack an understanding of their customers’ needs. Highway officials often provide overly conservative information about weather conditions, which can be misleading. Most state DOTs must go through the slow and inefficient processes of consulting numerous weather sources and interpreting weather data. More specific forecasts are needed so that forecasts can be integrated along particular travel routes. Travelers need more focus placed on measuring road surface temperatures, rather than atmospheric conditions. Road weather information systems research: http://www.aurora-program.org/ For information on 511: http://www.its.dot.gov/511/511.htm http://www.its.dot.gov/511/511weath.htm Last update: April 6, 2005 |
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