USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu OFFICE OF RESEARCH, DEVELOPMENT, AND TECHNOLOGY AT THE TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Home
                        Research
                        Turner-Fairbank Highway Research Center


            
            In This Section
        Explore Research and Technology
      
   Contact Us
      Turner-Fairbank Highway Research Center
      
                    
            United States Department of Transportation Federal Highway Administration6300 Georgetown PikeMcLean, VA 22101United States
      
          
    **Email:**TFHRC.webmaster@dot.gov
    If you are deaf, hard of hearing, or have a speech disability, please dial 7-1-1 to access telecommunications relay services.
                
                Office of Safety and Office of Infrastructure Project Results
    

    
    
          Geosynthetic Reinforced Soil-Integrated Bridge SystemEvaluation OverviewThe evaluation team examined the Federal Highway Administration's (FHWA’s) research and development process for the Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS) program. GRS technology consists of closely spaced layers of geosynthetic reinforcement and compacted granular fill material. FHWA has worked to evolve the technology into GRS-IBS, which blends the roadway into the superstructure.The evaluation focused on early research development, deployment decisions, barriers to GRS-IBS deployment, and whether GRS-IBS is a disruptive technology.Evaluation ResultsThe evaluation found that:FHWA pursued GRS-IBS research because it showed potential for saving time and money in the design and construction of single-span bridges.FHWA activities increased awareness of GRS-IBS among potential builders and bridge owners.FHWA activities and outreach improved the attitude of potential users toward GRS-IBS.Stakeholders mentioned multiple benefits from GRS-IBS, including cost savings, ease of construction, and time savings.RecommendationsA key recommendation was to make market research part of engineering research. Market research can help guide the selection of research topics, and improve the likelihood of implementing new technologies by identifying potential problems that might be encountered by technology users and—importantly—developing solutions prior to adoption.Gusset PlatesEvaluation OverviewThe evaluation team examined FHWA’s Gusset Plate Project to better understand how FHWA’s investment in gusset plate research has affected the design and rating of gusset plates.On August 1, 2007, I–35W Mississippi River Bridge in Minneapolis, MN, collapsed. The National Transportation Safety Board (NTSB) turned to FHWA to provide technical expertise during their investigation, and the NTSB then issued recommendations to FHWA to prevent similar catastrophic bridge failures. The Gusset Plate Project was an FHWA research project to assess the performance and design of steel gusset plate connections.Evaluation ResultsThe evaluation found that:FHWA provided vital support to NTSB to determine the cause of the I–35W Bridge collapse.FHWA’s work helped inform updates to the American Association of State Transportation Officials’ specifications.FHWA’s active and ongoing engagement of transportation stakeholders expedited delivery of new information regarding the design and load rating of gusset plates.RecommendationsThe evaluation recommended that FHWA should remain flexible on how its research funding is used. In this particular case, given the scale of the emergency and the immediate need for research and information, funds were redirected into the Gusset Plate Project. FHWA management was flexible with funding, and legislation at the time was also flexible enough to provide this accommodation.Precast Concrete PavementEvaluation OverviewThe evaluation team examined the outcomes and impacts of FHWA research and educational outreach related to precast concrete pavement technology. Precast concrete pavement (PCP) refers to high-quality, durable, prefabricated concrete panels used to repair roads during offpeak travel times. PCP panels are quick to install, and road maintenance professionals can use them for a range of projects in high-traffic areas.Evaluation ResultsSome of the main findings of the evaluation included:FHWA activities provided guidance to States interested in deploying PCP and furthered the development and number of PCP installations.PCP generates travel-time savings by reducing road-closure times and avoiding significant detours in areas that are difficult to repair (bridge approaches, shoulders, and ramps).PCP allows for overnight installation and is faster to install than traditional concrete.PCP is more durable and requires less maintenance and fewer repairs compared to cast-in-place and high-early-strength concrete.RecommendationsOne recommendation was that FHWA should continue to support PCP and document institutional knowledge without endorsing particular systems. An additional recommendation was that States should conduct trial installations prior to beginning construction. This has been shown to lower costs from unforeseen complications, increasing the overall return on investment for PCP usage.RoundaboutsEvaluation OverviewThe evaluation team assessed the effects of FHWA’s investment in roundabout research on the availability and quality of such research, the adoption of roundabouts in the United States, and the impacts of those roundabouts on safety, operational, and environmental performance of the United States transportation system. A roundabout is a circular intersection in which approaching traffic yields to circulating traffic. In the United States, roundabouts are often confused with traffic circles and rotaries.Evaluation ResultsSome of the main findings of the evaluation included:FHWA roundabout research increased awareness and changed attitudes in the transportation community toward the roundabout as a safety countermeasure.FHWA accelerated early adoption and contributed to an increase in the number of roundabouts built in the United States.The literature demonstrates significant safety benefits of roundabouts, as well as operational, environmental, and lifecycle cost impacts of roundabouts.RecommendationsA key recommendation was to research and promote information on roundabout costs and strategies for reducing roundabout costs. Initial roundabout capital costs appear to be a barrier to roundabout adoption, so additional research should be undertaken to identify the underlying cause for the high costs, in which the potential for cost savings may exist without compromising safety and performance benefits.**Completed reports can be viewed at https://www.fhwa.dot.gov/publications/research/general/18042/index.cfm.**
      
    
          Last updated: Monday, December 2, 2019 U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us