• Attenuation and Effectiveness of Triclopyr and 2, 4-D Along Alaska Highway Rights-of-Way in a Continental and a Coastal Subarctic Environment

      Barnes, David; Seefeldt, Steve (Alaska University Transportation Center, 2009-12)
      After more than 20 years of only mechanical brush cutting, ADOT&PF evaluated the use of herbicides to manage vegetation that interferes with line-of-sight and maintenance of the roadway. While researchers have investigated herbicide effectiveness and attenuation in more-temperate climates, little study has focused on cold regions. The purpose of this project was to measure the effectiveness and attenuation of two different selective auxin-type herbicides, 2, 4 dichlorophenoxyacetic acid (2,4-D), and 3,5,6-trichloro-2-pyridinyl acetic acid (triclopyr) in two subarctic climates; an extremely cold continental climate and a maritime climate. Conclusions from this study will aid the ADOT&PF in developing a plan for controlling vegetation along highway rights-of-way in Alaska.
    • Guidelines for the Use of Synthetic Fluid Dust Control Palliatives on Unpaved Roads

      Barnes, David; Connor, Billy (Center for Environmentally Sustainable Transportation in Cold Climates, 2017-07-06)
      The amount of small soil particles, dust, lost from typical unpaved roads to fugitive dust is staggering. A 1 km stretch of unpaved road can contribute over 2400 kg of dust to the atmosphere (4.2 ton/mile) in a typical 3-month summer season. Road managers typically manage dust from unpaved roads with various dust-control palliatives, which are effective for up to 1 year. Synthetic fluids are a relatively new category of dust-control palliatives. Unlike the more commonly used dust-control palliatives, such as salts, engineering guidelines do not exist for the application and maintenance of synthetic fluids on unpaved roads. To fill this void, we present through this document guidelines for road design and maintenance, palliative selection, application, and care of synthetic fluid-treated roadways.
    • Laboratory Procedure for Measuring the Effectiveness of Dust Control Palliatives

      Barnes, David; Connor, Billy (Alaska University Transportation Center, 2017-06)
      Creation of fugitive dust on unpaved roads results in the loss of up to 25 mm (one inch) of surface aggregate annually (FHWA, 1998). On these roads, shearing forces created by vehicles dislodge the fine aggregate fraction (silt and clay) that binds the coarse aggregate. Turbulent airflow created by vehicles loft these fine particles in plumes of fugitive dust that impact health, safety, and quality of life. The loss of these particles results in raveling of the road surface, culminating in large annual losses of surface aggregate. Chemical dust control (palliatives) is an attractive option. However, there are currently no accepted field or laboratory performance testing procedures for chemical road dust palliatives. The lack of a method to predict palliative performance forces engineers and road managers into a trial-and-error methodology or reliance on personal judgment and supplier claims to determine what will work best on their unpaved road or runway surfaces. The overall objective of this research was to finalize the development of a laboratory test procedure for evaluating different dust control formulations and application rates required to effectively control the airborne suspension of dust particles in the size range (aerodynamic diameter) of 10 μm or less.
    • Managing Dust on Unpaved Roads and Airports

      Barnes, David; Connor, Billy (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)
    • Managing Dust on Unpaved Roads and Airports

      Barnes, David; Connor, Billy (Alaska University Transportation Center, 2014-10)
      Fugitive dust emanating from vehicle traffic on unpaved roads and runways can have significant impacts on safety, health, quality of life, and the cost of maintenance. Managing dust provides a means of reducing these impacts. Shearing forces created at the interface between the surface and vehicle tires produce dust on unpaved surfaces. The dust produced becomes airborne as a result of turbulence created by moving vehicles. Once airborne, different monitoring techniques can be used to assess the amount of fugitive dust produced and to measure the effectiveness of dust management strategies. Communities can manage dust by properly constructing and maintaining the unpaved surface, reducing vehicle speed on roads, and with the proper use of dust palliatives. The proper gradation of aggregate, the right profile, and good drainage are all necessary for reducing fugitive dust from unpaved roads and runways. Moreover, reducing vehicle speed on unpaved roads can dramatically reduce the amount of fugitive dust and result in longer periods between maintenance events. Several different types of palliatives are available for both managing dust on unpaved roads and runways. The choice of palliative is dependent on aggregate gradation, traffic amounts, climate, and location (remote or accessible).