SPTC Brief: Evaluating Dust and Highway Safety in the Southern Plains

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SEPTEMBER EDITION

OVERVIEW: In this collaborative project, researchers from University of Tulsa, University of Texas at El Paso and Texas Tech University are investigating windblown dust, which poses significant hazards to highway safety by causing chain-reaction crashes. The dust contributes to accidents in two ways: sudden loss of visibility and loss of traction due to soil particles on the road surface. Although dust-related traffic accidents occur each year in the Southern Plains, no known studies have specifically investigated this issue in New Mexico, Oklahoma, and Texas. The lack of critical information hinders highway authorities in making informed and timely management decisions. Projected global changes, including changes in cli-mate extremes, land use, and land cover, are likely to bring more frequent and extreme dust emissions to the southwestern U.S., posing serious threats to transportation safety in the coming decades.

Figure 1: Location of dust emission hot spots (represented by red dots) and associated land cover characteristics in west Texas and eastern New Mexico. This map also shows numerous dust emission spots located adjacent to the main highways in this area.

Figure 1: Location of dust emission hot spots (represented by red dots) and associated land cover characteristics in west Texas and eastern New Mexico. This map also shows numerous dust emission spots located adjacent to the main highways in this area.

The SPTC research is identifying current and past dust source hot spots and associated geomorphic features and land use along the main highways. In west Texas and eastern New Mexico, the preliminary results reveal that sandy surfaces account for more than 80% of dust sources. Cultivated croplands are also a leading source (up to 57%) of dust. There are numerous dust emission hot spots that are located adjacent to the highways, including I-20 west of Midland, Texas, as shown in Figure 1.

This ongoing project uses remotely sensed and in situ measurements of land cover, soil, and vegetation data to quantitatively assess the spatial and temporal patterns of wind erosion hot spots that contribute to blowing dust on highways in New Mexico, Oklahoma and Texas. This study is focused on interstate high-ways where investment in surveillance and warning devices is greatest, and where high traffic volumes and speeds make the threat of blowing dust most hazardous. The ultimate goal is to develop an integrated modeling and monitoring system to mitigate the hazardous impacts of dust on highway safety.

Although most of the land surface does not erode in the Southern Plains, many areas and land uses may become erodible under disturbance, such as grazing of rangelands and plowing of cropland, and extreme wind events such as tornados. Previous studies by the research team in the Mojave Desert, California, and Canyonlands National Park, Utah showed that disturbed land surface could be as susceptible to wind erosion such as pure sand (Figure 2). A recent study of dust emission potential in the western U.S. revealed that dust emission would increase substantially in large parts of western Oklahoma and northern Texas as a result of extreme disturbance of current soil and vegetation (Figure 3).

Figure 2: Threshold shear velocity measured on the disturbed vs. undisturbed soils

Figure 2: Threshold shear velocity measured on the disturbed vs. undisturbed soils

Dust production from the hot spots at a given wind speed are being modeled with a quantitative model of dust emission, using the remotely derived and in situ measured soil and vegetation data. The modeling efforts are focused on the hot spot areas that have been identified early in the project. The modeling exercises will allow development of informative estimates of dust production at certain wind speeds.

Figure 3: Wind erosion potential for non-federal lands in the western US with disturbed soil and vegetation removal, showing the dust emission hot spots in western Oklahoma and northern Texas.

Figure 3: Wind erosion potential for non-federal lands in the western US with disturbed soil and vegetation removal, showing the dust emission hot spots in western Oklahoma and northern
Texas.

APPLICATION: The results of this research will be directly applicable to states within Region 6. The methodology and techniques employed in this project can also be applied to many states in the western U.S. where dust-related traffic accidents occur, such as Arizona and California.

BENEFITS: Results of this study will be immediately available for highway authorities to support informed management decisions on potential blowing dust hazard for highways. In addition, results will reveal the location of potential dust emission hot spots, which will benefit land managers in determining appropriate mitigation measures.

About the Researchers

Dr. Junran Li (Tulsa University) is the Principal Investigator on this project. Co-Principal Investigators are Dr. Thomas E. Gill (University of Texas at El Paso) and Dr. Jeffrey A. Lee (Texas Tech University). Please send inquiries to Dr. Li (jul009@utulsa.edu).

The Southern Plains Transportation Center is a consortium of eight universities in U.S. Department of Transportation Region VI: the University of Oklahoma, Oklahoma State University, Langston University, University of Arkansas, University of New Mexico, Louisiana Tech University, University of Texas at El Paso and Texas Tech University.

The SPTC provides a unique opportunity through multi-institutional initiatives to develop comprehensive, cost-effective, and implementable solutions to critical infrastructure issues facing the transportation systems of the region and the nation, and to prepare transportation professionals for leadership roles through Research, Leadership, Collaboration, Education, Outreach, Tech Transfer and Workforce Development activities.