Winter Maintenance Technology and Practices--Learning from Abroad

With a direct cost each year of $1.5 billion, snow and ice control on roadways in the United States represents a significant expenditure. Add to that $5 billion in indirect costs--corrosion, water quality degradation, and other environmental consequences--and it becomes clear that an increase in efficiency or effectiveness could result in substantial economic savings. In addition, better snow and ice control means better safety and mobility for the driving public and a reduction in negative environmental impact.

To find ways to improve winter road maintenance in the United States, Dr. Rand Decker of the University of Utah and six American transportation officials observed snow and ice control operations in Japan and Europe during a March 1994 International Winter Maintenance Scanning Tour. The Federal Highway Administration's International Outreach Program and the American Association of State Highway and Transportation Officials' National Cooperative Highway Research Program sponsored the tour to identify technologies and practices that might transfer effectively to the United States. Dr. Decker compiled information from the tour to write "Winter Maintenance Technology and Practices--Learning from Abroad." This report and the resulting proposals for establishing a National Winter Maintenance Program (NWMP) were published as the January 1995 issue of the National Cooperative Highway Research Programs' Research Results Digest.

Decker described important differences in the technology used abroad for snow and ice removal and in the ways government and private entities cooperate in accomplishing and financing snow and ice removal. As a result of their findings, tour participants recommended development of a national-level Winter Maintenance Program to oversee testing and evaluation of Japanese and European methods and ideas and distribute information on promising practices.

FINDINGS

The report divided findings into four categories: snow and ice removal equipment, snow and ice control materials and methods, winter maintenance management systems, and winter maintenance policy and funding issues.

Snow and Ice Removal Equipment

Next Generation Snow Plow -- Through a joint venture between private enterprise and government, Japan is developing a test vehicle that "features an optimized mold board configuration, an undercarriage-mounted plow with down pressure sensing and automated control loop, and a hydraulically actuated wing plow with height adjustments to and above the guard rail height." The new plow automates many driver tasks and provides monitoring of snow removal through video cameras.

Single-Lane-Obstructing Rotary Snow Plow -- Using a rearward conveying system, this plow moves 1,700-ton/hour of snow at 8 to 15 km/hour (5 to 9.3 miles/hour) while only blocking one lane of traffic. The plow requires two operators: a driver who also controls the rotary blade and a second person who operates remote controls that manage the conveyor system. Again, closed-circuit video cameras provide equipment operators with adequate views of the process. Tour participants felt this plow's ability to operate using only one lane would be especially valuable in United States cities with numerous bridges, viaducts, elevated roadways, and zones of heavy downtown traffic.

Melting Hauled Snow -- American cities dedicate large tracts of real estate and significant amounts of time to storing and manipulating hauled snow until it is fully melted in the spring. Japan is dumping gathered snow into melting tanks filled with treated waste water. After agitating the tanks to melt the snow, operators pipe the water into nearby rivers.

Hydraulic Conveyance of Urban Snow -- Along city streets, "snow flowing gutters" are filled with storm sewer runoff, treated waste water, or recirculated river water. Business and residential property owners voluntarily shovel snow from urban curbs, gutters, streets, and sidewalks into these gutters. Via "[a] network of box channel conduits with grated openings" the snow washes away with little labor expense.

Sectional Plows on Standardized Mounts -- In Europe, some snow removal trucks have universal plow mounts that allow operators to carry and choose between two and three different plow blades, depending on storm conditions. Universal mounts can also carry material-spreading attachments for use in pre-wetting anti-icing/deicing materials. In addition, German vehicles have "rubber shock/return springs on each individual segment of the plow and airflow spoilers mounted near the top of the plow moldboard" to "allow the vehicle to better respond to road surface irregularities, reduce snow cloud, improve motorists['] visibility of the snow plow truck, and enhance operator visibility."

Snow and Ice Control Materials and Methods

European Snow and Ice Control Vehicles -- Constructed with noncorrosive parts and outfitted with an antenna to let the equipment operator know spreading is in progress, European winter maintenance vehicles often feature "aerodynamic spoilers to create a favorable airflow field for material spreading." This airflow field also helps eliminate wasteful "bounce and scatter" of salting materials and prevent slush and mud on the road from splashing up to cover motorist warning signs mounted on maintenance vehicles. The Bavarian State of Germany has reduced salt consumption about 50 percent by applying liquid agents or pre-wetting dry salt just before application. This process does require careful calibration and maintenance of spread-rate controls for deicing materials.

Automated-Fixed Snow and ice Control Liquid-Spray System -- Controlled by an automated loop that monitors pavement and climate conditions, this guardrail-mounted system sprays ice and snow control and removal materials onto a bridge deck when needed.

Snow and Ice Control Materials and Storage -- Treated with anti-caking mixtures, snow and ice control materials in Europe are stored in covered enclosures made of noncorrosive treated wood. Blowing dry materials into storage areas saves space. Also, Sweden and Finland use sodium chloride of a finer gradation than the United States uses in its road-salting materials.

Other Snow and Ice Control Techniques -- Duplicating designs used for urban sidewalks and crosswalks, Japan has placed electric resistance wiring or hot water pipes under some sections of roadway. This treatment reduces the hazard of freezing roadways at tunnel entrances, sharp curves, and intersections. Japan also uses a low- pressure, low-velocity sprinkler system to produce a steady flow of water over dangerous sections of roadway. The system works best for melting accumulated snow when the temperature is just above or near freezing.

Winter Maintenance Management Systems

Blowing and Drifting Snow -- Blowing snow reduces visibility, and snowdrifts can make it impossible for motorists to get through. Japan has addressed these winter hazards with new snow fencing technology. An improvement over conventional snow fencing, Japanese "blower snow fences" (see photograph below) increase air flow in the area of the fence, resulting in less blowing snow on the roadway. In addition, the wind action produced reduces the amount of snow that accumulates behind the fence thus preventing the snow fence from becoming "full" and no longer doing its job. To work effectively, the new snow fences must be right next to the roadway--creating the incidental benefit that they take less right-of-way than conventional snow fences.
This effective snow fence and other innovative winter highway maintenance technologies are possible partly because of Japan's Hokkaido Development Bureau Construction Machinery Engineering Center. At the Center, a windtunnel uses clay particles to simulate the effects of highway cuts, structures, and facilities on blowing and drifting snow. The Hokkaido Office of the Japan Weather Association has also developed a computational simulation that presents in high-quality graphics information on decreased visibility, drift scour, and snow accumulation.

Snow Avalanche Hazards -- On mountain roads where avalanche zones present a danger to motorists and road crews, Japan and European countries install permanent avalanche countermeasures. These structures will cause an avalanche to flow over the top of the road, change direction away from the roadway, or dissipate before it reaches the road. In addition, "snow-supporting rakes" in areas of frequent snow slides hold back the snow and prevent avalanches from getting started. The University of Utah has joined the Japanese Nagaoka Institute for Snow and Ice Studies to further explore uses of and improvements on permanent avalanche-abatement structures.

Rubberized Traction Chains -- Easily installed and providing better driving quality than steel chains, these mats of rubber-covered steel cable have replaced steel chains in some areas. Japan has outlawed conventional steel tire chains.

Roadway Weather Information Systems (RWIS) -- Japan collects data on roadway microclimates from RWIS sensors that monitor temperature, wind speed, wind direction, precipitation, and humidity. Officials distribute information quickly to highway rest areas and on assigned radio frequencies. Japan and Europe also use such information to adjust speed limits on variable-message signs.
RWIS systems are expensive to install and maintain; however, resulting information allows quick-response application of anti-icing chemicals, thus preventing the bonding of ice to the pavement and saving time and materials. In addition, highway officials who know where weather is creating, or will be creating, roadway hazards can better decide where to assign personnel and machinery.

Winter Traffic Management Systems -- Video cameras along roadways enhance information from sensors to allow European and Japanese highway officials to provide timely information to motorists via radio, make remote-control changes in variable- speed/message signs, and close roadways where appropriate. Officials also use gathered information to call out emergency vehicles. In Japan, the development of a "winter maintenance information vehicle" is allowing crews to drive around gathering data that is radiolinked to a central location.

Motorist Information Systems -- RWIS technology and winter traffic management systems provide European and Japanese highway agencies with up-to-date information on roadway conditions and facilitate timely communication of that information to motorists. Changeable signs controlled from highway offices advise motorists of the need to reduce speed or choose a different route. Winter maintenance vehicles also display changeable message boards. As countries move into Intelligent-Vehicle Highway System technology, this information will couple with on-board digital maps to pinpoint hazardous conditions on certain roadways and suggest alternate paths.

Winter Maintenance Policy and Funding Issues

Level of Service -- Especially in Japan, the tour team found a strong sense of public ownership of citizen projects and pride in the country's infrastructure. Ice and snow control has become a joint project of government agencies, private sector businesses, and individuals. In Japan snow removal begins when accumulation has reached 5 centimeters (about 2 inches); and in many mild-climate areas, there is a public expectation that crews will always maintain bare roads. Germany has established standards for different classes of roads, and Bavaria plows daily as necessary but stops from 8:00 p.m. to 4:00 a.m. Scandinavian countries make snow-removal decisions based on measurements of the coefficient of friction taken on snow-packed roads by a truck-mounted friction meter.

Resources and Funding -- To make accurate comparisons between funding formulas for winter road maintenance in the United States and abroad, the team divided funds available for expenditures, labor, and equipment by lane kilometers maintained and average total amounts of snowfall in Japan, Europe, and the United States. The team found that Japan and Austria spent as much as two to three times more than the United States to maintain equivalent kilometers of road with equivalent amounts of snowfall. Equipment and personnel in the United States are expected to clear more snow from more miles of roadway than their counterparts in Europe and Japan.
Supplementing full-time public resources with rented equipment, temporary employees, and contracted help, Japan does most of its winter maintenance with government-owned equipment leased to private or quasi-private agencies. Sometimes contractors use their own dump trucks but rent government-owned spreaders or plows. Working at an hourly rate and paid on the number of equipment-hours worked, contractors often have continuing responsibility for specific small areas. The team found this practice promoted "familiarity and consistency of service."
Bavaria divides its 7 districts and 23 county-like subdivisions into 102 maintenance work areas each responsible for about 230 kilometers (about 143 miles) of roadway. Each area has two plow trucks, two "Unimogs" with blowers, and 30 full-time employees. Two rental trucks supplement the equipment during winter months.
Sapporo, Japan has a population of 1.8 million, 9,200 lane-kilometers (5,718 lane- miles) of roadway, and 5.0 to 6.4 meters (16.4 to 21 feet) of snow annually. Sapporo dedicates approximately $100 million (10 percent of its road maintenance budget) to snow and ice control. Half these funds come from national road-user taxes and half from local tax sources.

Partnership in Research and Development -- Sharing the risk and cooperating in the use of resources, government and private organizations are joining together in Japan to develop the next generation snow plow and other innovations in snow and ice removal. The Japanese Ministry of Trade and Industry introduced the studless tire, and collaborative efforts between government and private industry have changed motorists' buying habits so that almost all cars in Japan today use studless tires. The result has been longer-lasting roads and improved air quality. In the same spirit of cooperation, European government agencies supply private snow-removal contractors with publicly owned plows and spreaders.

RECOMMENDATIONS

The tour team concluded that winter roadway maintenance in Japan and Europe is superior to the United States, especially in: "equipment, anti-icing operations, road weather information systems, weather forecasting services, public information systems, policy issues, and environmental concerns." To evaluate Japanese and European technology, decide what might transfer effectively to the United States, and distribute information about promising innovations, the team recommended establishing a Winter Maintenance Program (WMP). The team envisioned three goals for the WMP:

1. sustain or improve levels of winter maintenance service with significant benefit/cost improvements,
2. provide an enhanced degree of environmental protection, and
3. place technology in service on operational maintenance sections within two winter seasons.

Copyright © 1997 by TranSafety, Inc.