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Transportation agencies generate and then pay to dispose of large quantities of lightly contaminated materials such as street sweepings, gravel shoulder cuttings, and other roadway materials. These lightly contaminated materials could be beneficially reused rather than landfilled. Unfortunately, due to regulations, stockpiling restrictions, inconsistent testing requirements, and long-term liabilities, there is a lack of reuse of these materials even though there is potential for significant cost savings. Due to unfavorable regulations, uncertainty in environmental impact, and unknown engineering properties, there are many disincentives or barriers to the reuse of these materials. Transportation agencies are generating increasing volumes of such materials, since new testing protocols detect contaminants in materials that had been previously thought of as clean. For example, due to improved contaminant detection technology many agencies are required to increase the frequency of street sweeping to meet Municipal Separate Storm System (MS4) standards, which in turn generates more lightly contaminated material. Once these materials have been deemed contaminated, the materials must be properly disposed of in regulated landfills which means more money is being spent on the disposal. DOT’s from across the country are interested in solutions to this costly and mounting lightly contaminated material problem.

Literature Review

The recycling of lightly contaminated transportation materials could potentially save agencies money, time, and resources. Recycling of lightly contaminated materials can be likened to the Environmental Protection Agency’s support of brownfield site cleanup. Brownfields are defined in the Small Business Liability Relief and Brownfields Revitalization Act as a real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant. Brownfield sites are typically lightly contaminated and have great potential for reuse (OSHA, 2008). Brownfield classification depends on several factors including the type of contamination, site conditions, local permit restrictions, time, and budget constraints. Therefore, it is important not only to observe the potential of the site, but also to conduct a comprehensive risk assessment before action is taken (Cooper 2014). This same approach could be taken for lightly contaminated transportation materials. Before brownfields, contaminated sites had to be cleaned thoroughly – to the point where children could ingest the cleaned soil. The cleaning to the point of ingestion has been found to be expensive and largely unnecessary. As long as the contaminants no longer pose a threat to people, the lightly contaminated sites do not need to be completely cleaned, brownfield sites only need to be eliminated of risk. The largest concern in brownfield remediation, and also the reuse of lightly contaminated transportation material, is the risk versus reward. To combat the potential risk, many states provide favorable regulations, grants, and incentives for those undertaking the cleanup of brownfield sites. Therefore, it is important to understand governmental regulations and incentives associated with brownfields and how that framework might apply to the reuse of lightly contaminated transportation materials (Rafson, 1999).


The primary objectives of this research are to:

  • Identify states that have favorable regulations related to the beneficial reuse of lightly contaminated transportation materials
  • Determine what makes favorable regulations function
  • Obtain and synthesize copies of favorable regulations and specifications
  • Obtain and synthesize testing protocols for lightly contaminated materials
  • Retrieve cost benefit information from projects that incorporated lightly contaminated materials
  • Identify possible end uses for lightly contaminated materials and associated risks
  • Create life cycle cost and risk analysis for each end use


Tasks to evaluate identified benefits and unintended risks include the following:

  • Canvas transportation agencies for material reuse success stories
    • Obtain sample specifications
  • Canvas regulatory agencies for visions on facilitating reuse and the concerns associated with possible reuse
  • Canvas DOTs to obtain existing analytical data on both contaminants and physical properties of typical materials
    • Example: Lightly contaminated soils, street sweepings, stormwater management system sediment, etc.
  • Collect and synthesize environmental and physical testing methods employed by DOTs to characterize lightly contaminated materials
  • Synthesize general characteristics of lightly contaminated transportation materials
  • Identify potential end uses for lightly contaminated material type
  • Synthesize life cycle costs and risk analysis for material reuse success stories
  • Evaluate benefits and risks of reusing lightly contaminated materials within the transportation system Right of Way (ROW)
  • Identify and evaluate existing tools that have been developed to help agencies make appropriate changes to practices, equipment, facilities, or agency policies when moving from materials to collection equipment.
    • Such tools may include materials for public outreach, citizen education, recommendations for policy, equipment, facility modification, and sources of maintenance personnel training and support
    • Compile existing best practices, training material, or other products into a single repository
    • Convert key information from technical reports into more “readable” formats for public outreach and non-technical users
    • Identify gaps in existing supports tools and equipment

Research Benefit

Industrial by-product reuse in many states has shown that proper reuse of lightly contaminated materials is a benefit because:

  1. Using lightly contaminated materials reduces the need for virgin materials
  2. Using lightly contaminated materials reduces the need to use valuable landfill space

Due to the many different regulations across the country, DOT’s do not have in place agreed upon standards, testing methods, or guidelines for the reuse of lightly contaminated transportation materials. Potential benefits enabled through the proposed research include:

  • Cost reduction associated with the use of less raw material
  • Cost reduction associated with less landfilling
  • Reduced hauling costs and carbon footprint
  • Resource conservations
  • Reduced use of virgin aggregate
  • Preservation of landfill space
  • Improved predictability of construction and maintenance costs
  • Public-private partnerships


State DOTs are aware of the costs associated with lightly contaminated transportation materials and are interested in research and guidance into the proper reuse of this material. State DOTs from across the country are concerned with the environmental impacts and engineering characteristics of these materials and will fully support research that details testing and proper use of these lightly contaminated transportation materials in a safe and beneficial manner.


Environmental Division in State DOTs

Sponsoring Committee




Research Period

12 months

Research Priority


PNS Developer

Andrew Graettinger and Winnie Okello

Index Terms

Lightly contaminated materials, benefit cost analysis, landfills, environmental impacts, life cycle costs, brownfields

Referenced Articles

  • Cooper, S., “The Remediation of Brownfield Sites.” Pollution Engineering 46.11 (2014): 20-22.
  • OSHA. “Brownfield Site Cleanup and Redevelopment.” OSHA Fact Sheet (2008): n. pag.
  • Rafson, H. J., and Rafson, R. N. Brownfields: Redeveloping Environmentally Distressed Properties. New York: McGraw-Hill, 1999.
  • United States, Congress, Committee on Government Reform. “Brownfields: What Will It Take To Turn Lost Opportunities Into America’s Gain.” 109ADAD, pp. 1-5. 109th Congress, 2nd session.

Interested in doing research?

Submit an abstract