Where the Weather Meets the Road A Research Agenda for Improving Road Weather Services (2004) / Chapter Skim
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1 Introduction
1 Introduction
Pages 15-24
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From page 15... ...
There can also be adverse environmental impacts if road treatment chemicals migrate from the road surface to the surrounding environment. Its omnipresence and influence on surface transportation makes weather information a necessity to most roadway users; according to a recent U.S.
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From page 16... ...
METEOROLOGICAL CONDITIONS THAT INFLUENCE THE ROADWAY ENVIRONMENT Nearly all weather conditions affect the roadway environment in some way, typically by affecting visibility, surface traction, or maneuverability of vehicles. Winter weather conditions, including snow accumulation, freez ing rain, icy surfaces, and blowing snow, have received the most attention by the transportation community because they can significantly impair the operability of the roadway system over a large region (Figure 1-1)
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From page 17... ...
Roadway maintenance personnel typically respond to winter weather conditions through a combination of plowing and chemical treatments intended to lower the freezing point of water, but challenges still remain in terms of determining the optimal response strategy for a particular winter storm. Although the impact of winter storms on the roadway system can be quite dramatic, more fatal accidents are attributed to rainy conditions than to any other inclement meteorological condition (Figure 1-2)
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From page 18... ...
When encountered unexpectedly while traveling at high speed, such haz ardous conditions can cause serious driver disorientation and lead to dra matic multivehicle accidents. Decreased visibility also can retard traffic flow as drivers properly reduce their speed, thereby reducing the carrying capacity of roadways; however, different drivers will reduce their speed differently in reaction to a sudden reduction in visibility, leading to large speed differentials and increased potential for accidents (OFCM, 2002b)
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. Any deviation from ideal driving conditions poses a potential threat to the maximum operability of the afflicted road.
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When visibility is less than 300 m, drivers may reduce their speed by 15 to 40 percent. Drivers endure over 500 million hours of delay annually on the nation's highways and principal arterial roads due to fog, snow, and ice (OFCM, 2002b)
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From page 21... ...
For example, state and local agencies spend more than $2 billion annually on snow and ice control operations and over $5 billion annually for infrastructure repair due to ice and snow damage. The average expenditure for winter road maintenance in 1999 was over $22.7 million per state or approximately 12 percent of their maintenance budgets (FHWA, 2003)
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From page 22... ...
CHALLENGES IN ADDRESSING THE ROAD WEATHER PROBLEM The fatalities, injuries, property damage, and economic costs associated with inclement weather present a significant road weather problem that is exacerbated by increasing traffic densities due to increasing population, vehicle ownership, and average annual miles traveled. This problem pre sents a number of challenges, both on a research level and when putting research advances into practice.
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From page 23... ...
The roadway environment is very complex from a meteorological perspective, requiring knowledge of atmospheric conditions and the processes that influence them on scales much smaller than regularly considered in operational frameworks. Road weather conditions are influenced greatly by the immediate environment, including local terrain, built structures, and land cover.
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From page 24... ...
In Chapter 5 the committee outlines a recommended coordinated national program to guide road weather research and transition scientific and technological advances into operations. The committee hopes that this report provides a useful framework to engage the transportation and weather communities and relevant stakeholders in the development of a strategic plan to guide road weather research.
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