NOTEWORTHY PRACTICE
 

TENNESSEE HIGH FRICTION SURFACE TREATMENT (HFST) 

Systemic Applications 

of High Friction Surface 

Treatment in Tennessee

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

In 2010, the Tennessee Department of Transportation (TDOT) 

created a Safety Office to analyze crash types, causes, and 

severity. In 2011, Tennessee adopted their Roadway Departure 

Implementation Plan, which included high friction surface 

treatments (HFST). Up to that time, TDOT had implemented 

HFST at ten locations statewide, primarily for lengthening 

bridge lifecycles, and were now interested in widespread 

deployment of the treatment as a safety improvement 

through the State’s HFST Initiative. 

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 What were the key challenges that needed to be 

addressed before the new practice could be implemented? 

Relatively new to HFST implementation, TDOT wanted to utilize a data-driven procedure to select sites where 

HFST could effectively improve safety as they launched the Initiative. TDOT regarded crash history and site-specific 

conditions related to pavement conditions, existing delineations, proximity to other curves, and other factors as 

important considerations for selecting appropriate sites. However, analysis of these criteria was no small feat and 

required field visits to each candidate location by Safety and Pavement/Materials Office staff. 

TDOT requires a defined need before obligating safety funds for any improvement. It was important to not only 

document how safety at a particular site may improve after HFST installation, but to limit HFST use to locations with 

sufficient pavement integrity, allowing HFST to last a full life span of up to 10 years. 

Describe the new practice: 

TDOT employed three approaches to help determine potential locations to include in their HFST Initiative, such as: 

REACTIVE PROACTIVE EVENT-BASED 

TDOT has an active The DOT has an exhaustive horizontal curve inventory TDOT considers other spot locations 

Road Safety Audit (RSA) and overlays crash data onto known curve locations as issues or opportunities arise, 

program and conducts to identify opportunities to further investigate. Curves such as locations experiencing 

an RSA at some locations slated for HFST installation through this approach are wet-weather related crashes or a 

with a significant crash included in TDOT’s HFST Initiative and the project is curve with close proximity to an 

history. programmed accordingly. upcoming HFST installation. 
NOTEWORTHY PRACTICE
 

TENNESSEE	 HIGH FRICTION SURFACE TREATMENT (HFST) 

TDOT mostly used the proactive approach to develop the candidate location list and relied on the following systemic 

process to do so: 

1 Overlay crash data onto horizontal alignment. 

TDOT overlaid three years’ of crash data onto their horizontal alignment inventory. 

2 Flag candidate locations and review data. 

Staff isolated all curves with four or more crashes in three years for further review, noting those that were 

indicated as weather- or speed-related in the crash report. 

3	 Perform field investigation.

Small teams of Safety Office and Pavement/Materials Office staff visited each candidate location to review and 

document curve geometry, sight distance, cross-slopes, existing safety improvements (e.g., signs, pavement 

marking), and evidence of past crashes (e.g., skid marks, damaged infrastructure). The team marked and 

documented potential limits for each HFST location and ensured signing and pavement markings were 

appropriate and in good condition. 

4	 Narrow the list. 

After field reviews, some locations were eliminated from the HFST Initiative for various reasons, including poor 

pavement integrity, crashes attributed to intersections within the curve, and others. Curves remaining on the list 

were grouped by proximity and programmed for installation. 

Key accomplishments, including roadway safety improvements: 

Since the launch of the HFST Initiative in 2011, TDOT has completed approximately 

50 HFST projects ranging from 2-lane rural to 5-lane urban locations, and 

approximately 60 locations were selected for HFST applications in the past year. TDOT 

plans to complete performance evaluations for the HFST installations, after collecting 

three to five years of crash data.
 

Additionally, TDOT held an “open house” event in 2015, as seen in photo, where 

they provided nearly 50 participants representing local agencies, engineering 

consultants, TDOT, FHWA, and universities with an opportunity to learn more about 

HFST application, benefits, and costs. The event included a live, on-site demonstration of HFST installation by the 

TDOT Materials and Test Division; presentations on HFST history, development, effectiveness, and installation; and an 

opportunity for questions and answers with TDOT and FHWA presenters. 

Source: FHWA 

HFST Open House by TDOT 

What technical and/or institutional changes resulted from the new practice? 

TDOT’s systemic HFST implementation has impacted local agencies; several have expressed a desire to try HFST 

and contacted TDOT for guidance and information. Along with their impressive local route inventory, local agencies 

in Tennessee have a solid funding mechanism that can sustain HFST installations on the local network. 

What benefits were realized as a result of the practice? 

Applying a systemic approach and rigorously vetting proposed locations ultimately helped leadership support the 

HFST initiative and moved it forward. The process also garnered support and proved to be beneficial at the 

local agency level. 

http://safety.fhwa.dot.gov

FHWA-SA-16-058

FOR MORE INFORMATION 

Joseph Cheung Danny Lane 

FHWA Office of Safety Tennessee Department of Transportation 

joseph.cheung@dot.gov danny.lane@tn.gov