To mitigate the effects of winter weather on the nation’s roadways, transportation professionals increasingly are turning to intelligent transportation systems (ITS) and other innovative technologies. U.S. researchers are developing many of these innovations, and also they are observing the solutions that highway agencies in other countries are using to battle ice and snow.
Teams of U.S. transportation experts traveled overseas three times in the past decade to study how other countries handle winter maintenance and operations. The first two scans, in 1994 and 1998, were devoted to maintenance, while a 2002 scan focused on ITS technologies related to winter operations.
The reviews were conducted under the Federal Highway Administration’s (FHWA) International Technology Exchange Program, which organizes studies of innovative foreign technologies and practices with potential to benefit the U.S. transportation system. The American Association of State Highway & Transportation Officials (AASHTO), Transportation Research Board (TRB) and FHWA jointly sponsored the 2002 scan.
Over the years, the interactions between the scanning teams and experts in other countries have resulted in many benefits for state highway agencies. In addition to direct investments in new technologies, the benefits include lives saved and costs cut because of the innovations.
“The face-to-face exchange of information with transportation professionals in other countries is invaluable,” said Leland Smithson, coordinator of the AASHTO Snow and Ice Pooled Fund Cooperative Program and co-chair of the first winter maintenance scan.
Road weather information systems (RWIS) technology, for example, is one innovation deployed as a result of the winter operations scans. RWIS—now used in 46 states and Washington, D.C.—includes various technologies for collecting, transmitting and disseminating information on weather and road conditions.
RWIS enables highway maintenance managers to treat roads before snow and ice can take hold. It offers traffic managers new ways to communicate road condition information to the public. It also provides valuable data for traveler information systems such as the nationwide 5-1-1 telephone system, which generates more than 1 million calls per month from travelers seeking real-time information on road conditions.
Take what is theirs
The 2002 scan included representatives from FHWA and state highway agencies, as well as the National Oceanic and Atmospheric Administration’s National Weather Service, National Association of County Engineers, American Public Works Association, academia and the private sector. The team met with representatives of a research institute, four major road authorities, a university and various private-sector organizations in Hokkaido, Japan’s northernmost island.
Team members also discussed advanced technologies with European highway experts at two conferences on winter road operations in Sapporo, Japan. The Standing International Road Weather Commission and the World Road Association sponsored the conferences.
Based on observations during the scanning study, the team developed an implementation plan that recommends further investigation of several technologies and practices that could be adapted for use in the U.S. They include winter maintenance equipment with enhanced sensors and control devices, integrated ITS corridors that use RWIS sensors for both winter-road management and traffic information, and measures for evaluating the performance of winter maintenance operations.
“Scans target countries where considerable research efforts are focused on snow- and ice-control technologies,” said Richard Nelson, co-chair of the 2002 scan and assistant director of operations for the Nevada Department of Transportation (DOT). “This allows us to take advantage of their research efforts to jump-start our programs.”
More plow power
During the 2002 scan, the U.S. delegation learned that innovative winter maintenance equipment developed in Japan and Europe includes advanced maintenance vehicle systems, automated vehicle location (AVL) and navigation systems, and vehicle-mounted performance-monitoring systems.
Japanese engineers, for example, have modified the design of snowplows so that the truck cab sits over the engine on a chassis. This cab-over-engine configuration gives the operator an unobstructed forward view of the roadway and helps keep snow that is blown over the top of the plow from accumulating on the windscreen.
Some vehicles also have dual front axles, which enable plow drivers to remove snow while traveling at high speeds. Other vehicles incorporate technologies to control the pressure on the plow blade automatically during snow and ice removal.
In Italy, an AVL unit is combined with global positioning systems (GPS) technology to provide chemical spreaders with enhanced capability. This capability includes preprogrammed variations in the application rate of snow- and ice-control chemicals on the roadway, and automated tracking and billing of materials that the spreader has dispensed.
In Japan, a system known as the millimeter-wave radar sensor is mounted on the front of a snowplow to detect obstacles in the roadway during low-visibility conditions, such as blowing snow and fog. Japanese engineers also are exploring several vehicle-mounted devices to determine the condition of snow- and ice-covered pavements. Among them are ground-view sensors that identify eight wintertime road-surface conditions, and researchers hope one day to use the sensors to adjust chemical applications automatically.
Snow- and ice-control equipment used in Japan and Europe generally is available in the U.S., but what to use and how to connect the pieces into an integrated system can be a challenge for many state and local highway agencies. The scanning team recommends that U.S. researchers continue to investigate vehicle-based winter maintenance technologies, including how to integrate those technologies.
More than just keeping roads clear, effective winter operations are a function of coordinated highway maintenance, traffic management and traveler information. Integrated ITS corridors feature a variety of technologies that combine maintenance with variable speed-limit signs and other types of information systems designed to keep traffic moving smoothly.
The scanning team found significant advances in Japan and Europe on improving communication systems and protocols between RWIS sensors and traffic operations centers. This work is part of an integrated ITS effort to use RWIS not only for winter road management, but also for traffic information and control.
The Finnish Road Administration, for example, uses RWIS information for automated traffic management and control decisions on E18, a road on the southern coast that carries cross-border goods between Finnish harbors and Russia. The E18 weather-related traffic management system covers a 15.5-mile section of the highway using RWIS sensors, variable speed-limit signs that are adjustable to reflect changing weather and road surface conditions, and variable message warning signs that communicate real-time travel information to motorists.
Japanese expressways have variable speed-limit signs that traffic control centers can change in response to wind speed, visibility and air and road temperatures. The centers collect information on winter-road conditions transmitted by weather observation equipment along the expressways and retransmit it to maintenance vehicles, variable message signs and rest area kiosks.
The scanning team recommended that U.S. researchers further investigate the use of weather-related information in ITS corridors around the world and develop an integrated system design concept that combines maintenance and traffic management.
The scanning team learned that many European countries are moving toward privatization of winter maintenance operations. The contractual relationships between highway agencies and contractors require a clear definition of wintertime service levels expected for a variety of road systems. As a result, agencies are developing methods to evaluate performance of winter maintenance operations.
Nineteen European countries are participating in an initiative to improve snow and ice control on roads and bridges. The project is being conducted by COST, an intergovernmental framework for European Cooperation in the Field of Scientific and Technical Research. The project, known as COST Action 344, includes six areas of research to generate improvements in program management, planning operations, operational practices, anti-icing products and spreading controls, measures to treat modern road and bridge surfaces, and driving information.
Researchers will conduct full-scale experiments employing various snow- and ice-control measures, will evaluate the results and then will develop best practices for performing and measuring winter maintenance activities. European officials anticipate that these best practices will lead to more effective management of winter operations, as well as fewer traffic delays and crashes.
In Japan, the Hokkaido Regional Development Bureau (HRDB) developed a guideline for maintenance of winter-road surfaces, and the Japan Highway Public Corp. published a national maintenance manual. Both documents describe recommended levels of service during wintertime conditions. The HRDB guideline includes road management goals for various highway facilities based on factors such as average daily traffic volume and road-surface conditions. Patrolling inspectors conduct visual inspections to evaluate the effectiveness of winter maintenance operations.
Many state highway agencies use performance-based standards on winter maintenance, whether for internal assessments or contract monitoring. The scanning team recommends that researchers compile U.S. and international performance standards applicable to winter maintenance and determine the circumstances under which various measures work best.
Here are the results
Several studies are under way already as a result of the scanning team’s recommendations, including a winter maintenance study organized by FHWA’s Transportation Pooled Fund Program, which enables federal, state, local and other organizations to combine resources to conduct transportation research studies. The pooled-fund winter maintenance study, led by the Wisconsin DOT, will conduct field tests of innovative materials, equipment and methods for improved winter highway maintenance. Researchers will carry out tests across a range of winter conditions to assess the effectiveness, ease of use and durability of the innovations.
In another spinoff from the scan trip, the TRB’s National Cooperative Highway Research Program is launching a project to document U.S. and international standards for winter maintenance operations. The objective is to identify the state of the art of winter maintenance practices, including policy development, implementation and measurement methods. Ultimately, the researchers plan to establish best practices that can be incorporated into the AASHTO Guide for Snow and Ice Control. Clearly defined standards will help highway agencies develop strategies to manage winter maintenance operations efficiently and effectively. More uniformity in winter maintenance, in turn, can improve mobility and safety on the nation’s highways.
Even simple solutions to common problems result from scans. During the 2002 Japan visit, Nelson noted that freeway signs were mounted at a slight downward angle.
“Our hosts indicated that this keeps the snow from accumulating on the sign and obscuring the message,” he said. The Nevada DOT initiated a field test of signs mounted at various angles to determine the most beneficial for keeping off snow, work that is expected to be completed next year.
Based on the scanning team’s success in Japan, FHWA and AASHTO are planning another winter operations scan in 2006 in conjunction with the World Road Association’s Winter Road Congress in Italy. That study will focus on European technologies.
“It’s an advantage to go to other countries and see technologies in actual practice,” Smithson said. “By learning from what others are doing, we can make a quantum leap in implementation in the U.S.”