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 FHWA Highway Safety Programs Home
                        Safety
                        Roadway Departure Safety
                        Keep Vehicles on the Road
                        Pavement Friction


            
            In This Section
        Pavement Friction
                Friction Management
                Continuous Pavement Friction Measurement (CPFM)
                Traditional Friction Treatments
                High Friction Surface Treatment
                Case Studies and Noteworthy Practices
                FAQs, Links, and Other Resources
      
   Contact Us
      Joseph Cheung
      
                    
            Program Contact
      
                    
            Office of Safety Programs
      
                
    **Email:**joseph.cheung@dot.gov
    If you are deaf, hard of hearing, or have a speech disability, please dial 7-1-1 to access telecommunications relay services.
                
                HFST Case Study: South Carolina DOT
sc_0.pdf (1.96 MB)
    
    
          FHWA-SA-15-056

A Cost-Effective and Time-Sensitive Safety Solution
"Image depicts a comparison of safety on the treated road before and after, showing a 56.5 percent decrease in total crashes per year (from 9.6 before to 4.2 after) and a 68.1 percent decrease in wet crashes per year (from 8.1 before to 2.6 after). The cost benefit in terms of net annual benefit is an 80 percent savings, with the reconstruction alternative costing $5 million and the HFST application costing only $1 million. The time savings comparison shows a benefit with HFST, which takes only 6 months to implement, versus the reconstruction alternative, which was estimated to take more than 3 years for design and construction."

**A one-mile section of US 25** in Greenville County had been a cause for concern for the South Carolina Department of Transportation (SCDOT) for many years. Located in rural, mountainous terrain, and often subject to inclement weather including rain, snow, ice, and fog, US 25 carries traffic on two lanes in each direction and is separated only by a damaged and brittle concrete barrier. US 25 changes dramatically, from a relatively straight road in North Carolina directly to this particular section in South Carolina with horizontal and vertical curves and a 6 percent grade. US 25 has a speed limit of 55 mph and carries approximately 10,000 vehicles per day with heavy truck traffic."Map of the one-mile section of Greenville US 25 treated with HFST. Copyright Google Maps."

SCDOT discovered a number of factors contributing to the high crash rates along this short section of US 25. One significant factor was that the concrete barrier's design did not allow for proper drainage, channeling water to the driving lane and shoulder. Speeding, inadequate pavement superelevation, and sight distance constraints also contributed to the safety issues at this location.

In 2000, SCDOT considered funding a major reconstruction project which involved replacing and updating the barrier wall and modifying the roadway's superelevation and drainage structures. However, with the project's estimate coming in at nearly $5 million, this project was unlikely to happen. Both costly and lengthy, the overall project development timeline for this alternative would have spanned approximately three years, and would have involved an extensive work zone and detour which would have inconvenienced local residents and drivers traveling through this area.

Over the years, low-cost measures of additional signing and markings were added along US 25, but these did not adequately address the excessive speeds and drainage issues, and the resulting safety improvement was minimal at best. At one point, a dynamic message sign (DMS) was installed to display a regulatory 45 mph speed limit during rainy conditions. However, due to the rural nature of this road segment and the wide road template, speeds remained excessive.

"Before and after photos of the treated roadway."

In 2008, a High Friction Surface Treatment (HFST) was applied to this curvy stretch of US 25. SCDOT had used this pavement treatment on ramp segments to increase skid resistance in locations where friction demand was high, but this one-mile project was the largest application to date, and at the time, it was unclear whether HFST would mitigate the hydraulic issues drivers experienced on this segment. With the planning process and installation complete in approximately six months, the HFST project cost SCDOT $1 million, which was 80 percent less than the previously considered reconstruction project.

A before and after study evaluating the HFST project's success on US 25 revealed significant safety benefits, with a 68 percent reduction in wet crashes and a 56 percent reduction in total crashes. Six years after HFST installation, SCDOT reports the pavement treatment is holding up very well, considering the high exposure to snow plowing.

To develop its current HFST specification, SCDOT used the AASHTO specification as the base model and integrated pieces from other States' specifications as well as their own experiences with the treatment. While their HFST specification is still evolving, SCDOT believes it strikes a good balance between quality materials and application, while still maintaining reasonable contractor expectations and competitive bidding.

*Citing a before and after study of seven HFST project locations, **SCDOT experienced an 81 percent reduction in wet crashes and 71 percent reduction in total crashes**. Since HFST has proven to be a very cost-effective safety countermeasure, SCDOT has installed 20 HFST projects, with approximately 20 more locations planned for 2015. Widespread deployment will be incorporated once the DOT identifies the horizontal curves throughout the State. The benefit/cost analysis for these locations has proven HFST to be a very cost-effective countermeasure.*

**For more information:**

**Joseph Cheung**
			FHWA Office of Safetyjoseph.cheung@dot.gov
			**Frank Julian**
			FHWA Resource Centerfrank.julian@dot.gov
			**Joey Riddle, Safety Engineer**
			South Carolina DOTRiddleJD@scdot.gov

Page last modified on June 17, 2015 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