Design Guidelines for Traversable Roadside Stormwater Check Dams in Clear Zone

State departments of transportation (DOTs) are facing increasing challenges of maintaining regulatory compliance with stormwater discharge requirements under the Clean Water Act. Finding available land to treat stormwater within the highway right-of-way is challenging, and the clear zone is often an ideal location. The clear zone is close to the source of the runoff and provides space for open, vegetated stormwater treatment measures that are effective and easy to maintain. Retrofitting roadway swales to include impermeable check dams to retain stormwater and promote infiltration is a cost-effective stormwater treatment approach for state DOTs. However, the AASHTO Roadside Design Guide does not provide specific guidance on check dams in the clear zone. Preliminary analysis has been completed on the trajectory of errant vehicles on rock check dams; however, simulation of various configurations, including check dam material, has not been completed. OBJECTIVE: This research would protect the traveling public while reducing treatment structure costs and right-of-way takes by creating guidelines for design of stormwater treatment check dams in the roadside clear zone. Check dams allow for the increased retention and filtration of roadway runoff within existing or minimally expanded right-of-way. This research will provide necessary crash test simulation modeling to inform guidance for traversable roadside check dams.

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=5895
• Supplemental Notes:
  • Contract to a Performing Organization has not yet been awarded.

Language

• English

Project

• Status: Proposed
• Funding: $750,000.00
• Contract Numbers:

  Project 25-76

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Project Managers:

  Brooks, Michael

• Start Date: 20251028
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Clear zones; Crash tests; Dams; Guidelines; Highway design; Right of way (Land); Runoff; Swales; Water quality management
• Subject Areas: Design; Highways; Hydraulics and Hydrology; Safety and Human Factors;

Filing Info

• Accession Number: 01956602
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 25-76
• Files: TRB, RIP
• Created Date: May 28 2025 1:28PM