Warming up to technology
When it comes to doing battle with Old Man Winter, street and highway officials are finding that brains, not brawn, is the way to go. Instead of relying on massive trucks with wide plows and powerful engines, or attempting to smother ice with blankets of salt, road crews increasingly are putting high-tech equipment and software to work and using preventive “anti-icing” methods.
Anti-icing involves the application of liquid brine and mixtures including such chemicalsas liquid magnesium chloride, liquid sodium chloride and potassium acetate to roadways to prevent the formation of bonded snow and ice. The process saves money by cutting salt usage, and it reduces harm to the environment and ensures safer roads for motorists.
De-icing, by contrast, is an after-the-fact action that involves spreading salt or other substances onto roadways to melt existing snow and ice. The de-icing process is performed precisely to reduce salt consumption and minimize damage to infrastructure, vehicles and the environment.
Augmenting those strategies are road weather information systems (RWIS), which gather data from solenoids, sensors and weather monitoring equipment. Remoteprocessing units, also known as environmental sensor stations (ESS), digest data such as temperatures (air, pavement surface and pavement subsurface), humidity, precipitation, wind speed and direction, and barometric pressure.
The ESS then feed that data to central computers, triggering either an automatic or manual response. The latter typically involves officials who give orders to their snow and ice removal crews, activate anti-icing sprayers, adjust variable message signs and, in some cases, update information available to motorists on the Internet. Highway departments frequently supplement RWIS data with weather data they purchase from private forecasting firms, and it is becoming more common for bordering states or neighboring municipalities to share RWIS data, according to John MacMullen of the Kansas City, Mo.-based American Public Works Association.
The brains behind anti-icing RWIS and anti-icing frequently go hand-in-hand because the former helps determine the composition of the latter — the blend, concentrations and types of chemicals that will be applied to the roadway. “The major point of all of these chemicals is to depress the freezing point,” says Rob Fox, product manager for Seattle-based Coastal Environmental Systems, an RWIS manufacturer. As for determining which anti-icing chemicals to use, “It’s all a matter of balancing out cost and effectiveness,” Fox says.
Some chemicals are used for both anti-icing and de-icing, according to Tony Myhra, product manager for Fort Madison, Iowa-based Cryotech Deicing Technology, a manufacturer of calcium magnesium acetate (CMA). At least 12 state DOTs use CMA mixed with salt to alleviate corrosion.
Generally, users purchase CMA in a solid form and mix it with liquid solutions. “The advantage of putting down liquids is they will stick to the pavement,” Myhra says. “The problem with the dry stuff is that traffic or wind can move it out of the way.”
Some RWIS are integrated with automated bridge deck anti-icing systems featuring nozzles that spray the roadway with anti-icing chemicals pumped from storage tanks underneath the bridge. Such systems typically are used on bridges or stretches of roadway that either are notoriously treacherous during inclement winter weather or are so remote that it is costly and time-consuming for maintenance crews to reach them.
Europe has used such systems since the early 1970s, but they arrived on the American scene only recently. Two years ago, the National Cooperative Highway Research Program funded installation of a bridge deck anti-icing system on the South Street overpass at Interstate 215 in Salt Lake City.
Since then, Chicago-based Energy Absorption Systems has obtained the license to manufacture the Odin Anti-Icing System, which employs hardware, software, communication interfaces and other equipment to monitor weather conditions at a given location. Depending on the configuration, the system can alert DOT officials when conditions are conducive to icing, or it can automatically spray anti-icing chemicals on the road surface. Three northern Minnesota bridges — two on Route 37 and one on Interstate 35 — are equipped with the system. Wisconsin uses it on Interstate 43 in Delevan, and Kentucky uses it on Interstate 75 in North Corbin.
Another bridge system uses electrically heated pavement to melt snow or ice. Chicago-based Superior Graphite Co. owns the technology, which combines synthetic graphite, asphalt and electricity to heat bridge decks or airport runways. The New Jersey DOT has installed the system on a bridge at Deepwater.
Common language Incompatibility of RWIS hardware and software from different manufacturers has made for a modern day Tower of Babel, but work is under way to eliminate that problem. The Joint Committee on the National Transportation Communications for ITS Protocol originally was formed to develop standard electronic protocol for traffic signals. The committee, consisting of state and federal officials and representatives of trade associations including the American Association of State Highwayand Transportation Officials, now is trying to hash out a uniform communications protocol for RWIS.
A common language will make it easier to integrate data from diverse sources. That is the mission of Foretell, a public-private partnership that will assimilate and filter weather data from disparate sources and disseminate detailed road and weather information to state highway departments and the traveling public.
The Federal Highway Administration (FHWA) is partially funding the initiative, and the Iowa Department of Transportation is the lead public sector agency. Leesburg, Va.-based Castle Rock Consultants, a transportation consulting firm, is the private sector lead.
Foretell is perhaps the most ambitious weather data integration project ever undertaken. Data from satellites, supercomputers, radar, wind profilers, airborne platforms, weather stations and RWIS will be integrated. The National Weather Service, National Oceanic and Atmospheric Administration, Department of Defense, Federal Aviation Administration and Canada’s weather service, Environment Canada, all will supply data.
“We’re trying to get much better, more detailed and time-specific information on weather that relates to snow and ice control,” says Peter Davies, chairman of Castle Rock Consultants. He adds that the National Weather Service is nearing completion of a $4 billion modernization program that bodes well for Foretell. “[The NWS] is vastly upgrading its computers and forecast capabilities,” Davies says. Foretell, phase one of which should be ready for implementation late this year, is one of the many intelligent transportation systems (ITS) resulting from ISTEA. Within five years, its creators want to make its data available to the states.
Foretell also is intended to stretch the snow and ice control data to promote greater safety for motorists. “We believe we need to disseminate seamless information to the public,” Davies says. That will be done through a variety of media, including commercial radio and TV, conventional and cellular telephones, pagers, the Internet, and various ITS information systems such as highway advisory radio and variable message signs.
Acting on weather data No matter how accurate, timely and plentiful the RWIS and related weather data are, they will be of little use if those who act on them do not have excellent equipment and training. In that regard, the Federal Highway Administration has taken an active role in spreading the gospel of high-tech snow and ice control. The agency has set up “Ice Warriors,” a team of state DOT officials who travel across the country explaining anti-icing and other winter maintenance techniques to street and highway officials.
Aside from the pervasive anti-icing and high-tech initiatives already mentioned, numerous other pilot programs either are planned or are under way for new equipment and new approaches. For example, three Rocky Mountain state DOTs are testing equipment that will automatically close roadways a few seconds after an avalanche starts.
“The goal is not to forecast avalanches, but to detect the onset of avalanches,” says Rand Decker, associate professor with the University of Utah’s Department of Civil Engineering. Decker says an avalanche’s “time of descent,” the time it takes it to travel from its point of origin to the roadway below, often is between 30 seconds and a minute.
Invasive sensors — “geophones” implanted in rock or soil — can detect avalanches in time to trigger a response such as the closing of railroad crossing gates to prohibit access to the roadway below. Funding for the project comes from DOTs in Idaho, Utah and Wyoming, which already are trying out the system; from the Colorado and Washington DOTs, which eventually plan to implement it; and from the FHWA’s Office of Technology Applications.
Researchers also are finding ways to make existing equipment better. Under the leadership of Iowa State University’s Center for Transportation Research and Education, DOTs in Iowa, Minnesota and Michigan are working with Rockwell, a Cedar Rapids, Iowa-basedtransportation technology firm, to enhance mainstay equipment such as snow plows. Each snow plow cab has been equipped with a display that gives drivers the air and road temperatures. In addition, two-way data message capability is included along with push-button access to engine condition, plow positions and an inventory of on-board chemicals and sand.
Air and pavement temperature sensors measure current conditions to aid drivers in choosing the best mixture of salt, sand and brine. A friction- measuring device determines how slippery the road is after plowing and feeds that data into a materials application control. The optimum mixture of salt/sand and brine is applied automatically.
Each plow also boasts an on-board computer that monitors engine performance — rpm, mpg, temperature, etc., and tracks the amount and ratio of snow and ice control materials, including salt, sand and brine. Dispatchers and maintenance departments can monitor engine conditions and other on-board systems remotely to reduce maintenance costs.
The high-tech plows also put technology to work to increase motorists’ safety. Fiber-optic lighting is used for high-visibility hazard flashers and plow marker lights, making it easier to see the plows in blizzard-like conditions.
Global Positioning Systems enable dispatchers to track the plows’ locations and can be used to alert drivers of snow-covered fire hydrants or other potentially hazardous obstructions. Theoretically, a GPS-equipped fleet could save time and fuel by enabling dispatchers to send the nearest plow to areas with deteriorating weather conditions, accidents or emergency medical situations.
The prototype testing has only scratched the surface of what is possible, according to Rockwell spokesman Robert Woods. Eventually, data from maintenance vehicles could be made available through an Internet link to provide precise, up-to-date road conditions to the public. Timely information for area travelers could be updated with electronic links to local news media or variable message signs.
New methods Sometimes, the way something is done is just as important as the equipment used to do it. Yet new methods often dictate the invention of new equipment, bringing about change on two fronts. Such is the case with the “zero velocity” salt spreader.
The device projects salt or other deicing or anti-icing materials off the rear of a truck at exactly the same speed that the truck is traveling. When the substance hits the pavement, it has no momentum to carry it forward or off the road. In addition to reducing waste, zero velocity spreaders enable salt truck drivers to travel at about the same speed as surrounding traffic, thereby reducing the chance of accidents when visibility is poor.
Because zero velocity spreaders use salt at a slower rate than conventional spreaders, drivers reduce the time they spend driving to and from stock piles to replenish their loads. Studies by the Wisconsin and Pennsylvania DOTs have estimated that the spreader reduces salt consumption from 25 to 70 percent, according to Dave Gelhar, a spokesman for zero velocity spreader manufacturer Tyler Industries, Benson, Minn.
Durability is crucial While today’s high-tech approach to snow and ice control may be phasing out the brute force and none-too-subtle de-icing methods of the past, it must retain at least one old-fashioned attribute: durability in harsh conditions. After all, the most sophisticated piece of equipment in the world is utterly useless if wind, humidity or ice disables it.
That fact is not lost on manufacturers of RWIS and other snow and ice control equipment. “In most cases (regarding) the robustness of the system, the problem is not with the sensors; it is with the communication link between the sensors and the user,” says Utah’s Decker. He and other researchers are working hard to ensure reliability on the communications front.
Their jobs, and the jobs of street and highway officials nationwide, will be aided by the extension of ISTEA, which will continue allocating funds for ITS projects and research.Last month, the Senate passed a six-year, $214 billion ISTEA extension, and the House was expected to pass its version of the bill this month.
It is a college without a campus, a football team or tuition. It offers courses that can be completed in one day. Yet the Maryland Snow College performs a valuable service that ultimately may save lives and prevent serious injuries.
Run by the State Highway Administration’s Office of Maintenance, the college teaches street and highway officials the latest techniques and technologies for fighting snow and ice. A “certificate of completion” is offered for the following three courses:
* Emergency communications. Includes operation of portable, mobile and CB radios; communication nuances like breathing, resonating and using proper articulation; understanding snow emergency procedures; and properly conducting incident response. * Roadway plowing. Covers pre-season preparations including staff meetings, a “dry run” and equipment inspection; types of roadways and surfaces; roadway configurations; types of plows; and plowing tips and techniques. * Weather interpretation. Explains how weather systems work, discusses forecasting and reviews basic weather terminology. Also offers a rundown on the weather data available on the State Highway Administration’s computers and depicts data with schematics and diagrams.
Attendees must pass a written test to obtain certification in each of the classes, according to Larry Russ, lead instructor for the Office of Maintenance training and certification team. Instructors employed with the Maryland DOT teach the day-long courses, augmenting their presentations with audio visual presentations and actual equipment displays. The classes are offered from spring through fall.
Each class typically has about 20 to 25 people, and courses are offered in different parts of the state. Although the classes are designed primarily for Maryland transportation officials, Russ encourages officials from other states to attend the classes to get ideas. “They’re welcome to sit in on the classes. It’s just a part of the information-sharing process that benefits everyone,” he says.
Since 1992, when classes were first offered on a regular basis, Russ has sent out snow college information to DOTs in several other states, including New York, Wisconsin, Michigan, Virginia and West Virginia.
East of Seattle, on a 40-mile stretch of Interstate 90, Snoqualmie Pass receives an average of 44 feet of snow and 60 inches of rain annually. Snow, rain, and overcast or foggy conditions prevail about 80 percent of the time, and avalanche hazard warnings sometimes are issued.
In conditions like those, motorists need more than metal signs to deliver them safely through the weather. As a result, the Washington DOT has installed nine variable message signs that issue varied speed limits as well as information on road conditions, tire chain requirements and highway closures. The signs are part of Travel Aid, an intelligent transportation system designed to improve safety and minimize accidents.
The system’s intelligence begins with wide aperture radar that tracks vehicle speeds, while six weather stations monitor temperature, humidity, precipitation, wind and road surface conditions. The information from all sources is gathered and transmitted by packet radio and microwave transmission to a control center. Travel Aid then calculates safe speeds that are confirmed by DOT staff members and transmitted to the variable message signs.
The signs are crucial to managing the more than 20,000 vehicles that travel through the pass each day, according to the Washington DOT. “Weather conditions in the mountains change rapidly,” says Larry Senn, Travel Aid project manager. “Radio stations generally do not broadcast conditions frequently enough to keep travelers up on the latest road conditions. Travel Aid now gives motorists and truck drivers immediate information on weather and speed limits as they approach the mountain.”
Senn adds that Travel Aid’s weather data soon will be available on the Internet. Last fall, the Washington DOT installed a surveillance camera on Snoqualmie Pass to provide Internet users with a view of real-time traffic conditions. The department plans several more camera installations.
Travel Aid is a component of Smart Trek, a partnership of 25 Northwest public agencies. The project is funded by the Washington DOT, the Federal Highway Administration and the University of Washington.