NOTEWORTHY PRACTICE 

WASHINGTON	 HIGH FRICTION SURFACE TREATMENT (HFST) 

High Friction Surface Treatment Applications

by Thurston County, Washington
 

 What was the safety issue, problem, or gap? 

From 2006 to 2010, Thurston County, Washington experienced 177

fatal and serious injury crashes on the county’s road network, of which

about 70 percent is rural. Similar to other local road networks, the

crashes were not concentrated in specific locations. 

The County had been deploying many low-cost safety improvements

such as signing, pavement markings, and rumble strips, but there

were still sites where these solutions were not feasible. As a result,

Thurston County sought another relatively low-cost and proven safety

countermeasure with minimal physical impacts to the roadway and

surrounding environment. 

 What were the key challenges that needed to be 

addressed before the new practice could be implemented? 

The County considered high friction surface treatments (HFST), as shown in photo above, in 2012; but the lack 

of local cost data, staff training, materials, and installation cost, coupled with the agency’s lack of experience 

implementing the treatment, eventually led them to abandon the idea. 

However, after learning of the successful HFST application at the Marquette Interchange in Milwaukee, Wisconsin 

that resulted in a 96 percent crash reduction,1

 the County re-engaged in examining the use of HFST. After applying 

for and receiving HFST demonstration site funding through the Federal Highway Administration’s (FHWA) Every Day 

Counts 2 (EDC2) initiative, the County prepared for their first HFST installation. 

Describe the new practice: 

Thurston County developed their HFST implementation strategy consisting of the following objectives: 

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HFST at Thurston County Horizontal 

Curve Demonstration Site 

1. Identify Partner Agencies. In this case, the County asked for technical assistance and support from the 

Washington State Department of Transportation (WSDOT) Local Technical Assistance Program (LTAP) and the 

FHWA Washington State Division Office. 

2. Consider Proven Safety Countermeasures. Both Washington State LTAP and FHWA partners expressed 

an interest to promote HFST on local roads, especially after Thurston County crash data indicated there was 

a considerable proportion of fatal and serious injury collisions (e.g., wet weather, skidding/out of control 

collisions) that may be reduced by the implementation of HFST. 

1 Mike Moravec, “High Friction Surface Treatments and High-Crash Horizontal Curves.” Arizona Pavements and Materials Conference in Phoenix, Arizona. 

November 13, 2013. Available at: http://pavement.engineering.asu.edu/wordpress/wp-content/uploads/2013/12/High-Friction-SurfaceTreatments-Mike-Moravec.pdf. 
3. Use Data-Driven Methods to Develop a List of 

Candidate Locations. Crashes were widespread and 

not concentrated, so Thurston County chose a systemic

approach for site selection. The County analyzed 

their road inventory and crash data provided by the 

County Road Administration Board,2 and concluded 

that roadway departure crashes coded as skidding/ 

out of control accounted for 27 percent of fatal and 

severe crashes from 2006 to 2010. This crash type 

was used to identify locations that may benefit the 

most from HFST. County staff then investigated crash 

density, coupled with roadway functional class, which 

narrowed the number of sites to analyze. Thurston 

County used FHWA’s Systemic Safety Project Selection 

Tool to identify candidate sites for HFST application 

by reviewing clustered data, assessing risk factors, and 

determining threshold values to prioritize sites.3

4. Identify Funding Opportunities to Explore 

Innovative Solutions. Through FHWA’s EDC2 

initiative, Thurston County secured funds to cover 

materials and contract installation at one site. 

5. Be Maintainable and Sustainable. County staff was 

responsible for maintaining the safety investment 

and received HFST installation training through the 

demonstration for future implementations. 

6. Share Efforts with Other Safety Partners. The 

County hosted a peer exchange featuring an HFST 

installation demonstration with representatives 

of local agencies, industry, the Washington State 

Department of Transportation, FHWA, and the 

Western Federal Lands Highway Division attending 

the event. The demonstration included a manual 

application of HFST by Thurston County crews, as 

shown in photo above. 

7. Make Efficient Use of Resources. Training County 

work forces on HFST installation techniques allowed 

for continuous maintenance of future investments 

and for cost-effective HFST installations at small sites 

that may be typical of local road applications. 

2 Washington State County Road Administration Board, available at: 

https://www.crab.wa.gov/. 

3 FHWA’s Systemic Safety Project Selection Tool is available at: 

http://safety.fhwa.dot.gov/systemic/. 

Source: Scott Davis, Thurston County , Washington 

NOTEWORTHY PRACTICE
 

WASHINGTON HIGH FRICTION SURFACE TREATMENT (HFST)
 

Demonstration of HFST Installation 

using Manual Techniques. 

Key accomplishments, including roadway 

safety improvements: 

In addition to County staff successfully installing HFST at 

a third site in October 2014, they have motivated other 

Washington State counties, including Kitsap, King, and 

Lewis Counties, to take great interest in HFST through peer 

exchanges. Both Kitsap and Lewis County now have HFST 

installations on their respective county road network. 

Thurston County is planning to use HFST more frequently 

and self-install at least one project per year. 

What technical and/or institutional changes 

resulted from the new practice? 

Thurston County utilized the FHWA’s Systemic Safety 

Tool for the second time as part of a system-wide safety 

review and is now using the tool for the third time 

focusing on speed-related collisions in partnership with 

the Washington State Traffic Safety Commission and the 

County’s Prosecuting Attorney’s Office. 

What benefits were realized as a result of the 

practice? 

There have been no reported collisions at the County’s 

HFST demonstration sites since the installations, though 

the statistical expected value was about 3 crashes per year. 

Additionally, since Thurston County trained their work 

force in HFST installation methods, they have the option 

to complete implementations and future maintenance 

without contracting the work. 

FOR MORE INFORMATION 

Joseph Cheung Scott Davis 

FHWA Office of Safety Thurston County (Washington) Public Works 

joseph.cheung@dot.gov davissa@co.thurston.wa.us 

http://safety.fhwa.dot.gov 

FHWA-SA-16-060