PENNSYLVANIA 

SR 611-Northampton County 

CASE STUDY HIGH FRICTION SURFACE TREATMENT (HFST) 

Successfully Disseminating the Practice

Maintaining required pavement friction values in horizontal curves 

is crucial for keeping vehicles on the roadway. 

Thinkstock/MarcoCoda

Meeting the required friction demand at curves is a challenge; vehicles require even greater friction on wet road surfaces, 

making curves more susceptible to crashes. High Friction Surface Treatments (HFST) are pavement treatments that use 

bauxite and epoxy binder to provide long-lasting and skid-resistant properties to the roadway. 

BACKGROUND 

Despite PennDOT’s signing and pavement marking improvements, one particular horizontal curve on the two-lane State 

Road (SR) 611 in Northampton County had thirteen wet pavement crashes in ten years in the southbound direction. The 

lack of super-elevation and presence of an intersection within the curve were contributing factors to safety concerns. 

ADDRESSING SAFETY CONCERNS WITH INNOVATION 

Lower-cost strategies, such as advanced curve warning 

pavement markings or chevron signs, did not eliminate the 

safety concerns; as a result PennDOT explored innovative 

solutions and became interested in HFST, which appeared 

promising for reducing roadway departure crashes within 

curves. As a pilot project, PennDOT hired a contractor to 

install HFST for the first time in June 2007, as a solution to 

the safety issues on the SR-611 curve. The treatment was 

approximately 800 feet in length and only installed in the 

direction where the past crashes occurred. 

SR 611 WET PAVEMENT CURVE CRASHES 

HFST Installed 

0

1997 2007 2015

13

PennDOT’s persistence in addressing safety issues at this 

location achieved the results they desired. In contrast 

to the past attempts to improve safety, the location 

experienced no wet pavement crashes in the eight years 

after HFST installation. 

SHARING THE PRACTICE.... AND THE 

CRASH REDUCTIONS 

Results from the first HFST implementation on SR-611 were 

extremely encouraging. While the performance of the 2007 

HFST implementation was being thoroughly evaluated, 

PennDOT continued to experience numerous wet curve 

crashes elsewhere in the State. PennDOT applied the 

treatment to fourteen additional sites in 2012, all identified 

based on high frequencies of wet pavement crashes. 

The Federal Highway Administration’s (FHWA) Every Day 

Counts (EDC) initiative encouraged PennDOT to further 

increase HFST applications in 2013. 
Erie 1

Mifflin 2

Centre 1

Clearfield 2

Clinton 2

Lackawanna 2

Luzerne 1

Pike 2

Susquehanna 1

Lehigh 20

Northampton 16

Berks 18

Schuylkill 1

Monroe 2

Montgomery 8

Chester 10

Delaware 4

Philadelphia 3

Dauphin 3

cumberland 2

Franklin 3

adams 1

lancaster 2

lebanon 3

York 2

Blair 4

Bedford 3

Cambria 4

fulton 2

Huntingdon 1

Armstrong 4

butler 2 

Clarion 3

Indiana 3

jefferson 2

Greene 1

washington 3

Fayette 3

Westmoreland 3

 150

 PENNSYLVANIA 

HIGH FRICTION SURFACE TREATMENT (HFST) 

“In my [experience], HFST is one 

of the best materials I’ve seen in 

terms of one-to-one correlation of 

immediate and definite effects 

on making a roadway safer.” 

Steve Pohowsky 

PennDOT, District 5 

Safety Program Specialist 

1 Pennsylvania Counties 

Erie 

0 0 0 0 0 1 Crawford Warren McKean Potter Tioga Bradford Susquehanna Wayne 

0 0 0 0 Venango Forest Sullivan 2 0 Cameron Wyoming 0 Lycoming Lackawanna 

Mercer Elk 0 0 Clinton 0 0 3 2 1 2 Columbia Luzerne Monroe Clarion 0 Lawrence Butler Montour Jefferson 2 Centre 0 0 2 0 Clearfield Carbon Union 2 Armstrong 1 0 0 0 Northumberland Northampton Beaver 4 Indiana Snyder Schuylkill 

0 3 2 1 Lehigh 16 Cambria Mifflin 0 Allegheny Blair 1 Dauphin 20 Juniata Berks 

0 4 4 0 Lebanon Bucks Perry 3 18 3 3 0 Washington Huntingdon Montgomery Westmoreland 2 3 Cumberland 8 2 

0 Lancaster 10 3 3 3 2 3 2 4 Chester
 Phila

Greene Fayette Somerset Bedford Fulton Franklin Adams York
 1 1 Delaware 

HFST Implementation Sites 

1-5 6-10 >10 

As the HFST implementations built 

momentum, PennDOT wanted to 

develop a manageable program and 

introduce the countermeasure to 

locations throughout the State. In July 

2013, the agency determined the top 

50 locations for consideration based 

on wet pavement crash data, with 

locations distributed among each 

District. By the end of 2013, PennDOT 

applied HFST at 19 sites in total. 

To track HFST’s performance, 

PennDOT developed a spreadsheet 

with five years of ‘before’ crash data as 

soon as the treatment was installed 

and inserts ‘after’ data as available 

to facilitate the evaluation process. 

All 19 HFST installations, where 234 

crashes – 164 of which were wet 

pavement – and 8 fatalities in total 

had occurred in the five years prior 

to the treatment, have experienced 

17 crashes and zero fatalities to date 

since their implementation. 

Additionally, PennDOT tracks 

pavement friction values at HFST 

sites. The HFST implementation sites 

averaged skid numbers of over 70 

Pike 

2

delphia 

when measured multiple years after 

the installation, whereas traditional 

pavement overlay initial friction values 

are 50-55 and decline into the 40s 

within a few years. 

DEVELOPING A 

SPECIAL PROVISION TO 

INSTITUTIONALIZE HFST 

In 2013, the pace of HFST 

implementations slowed down 

as materials and pavement staff 

shifted their focus to developing a 

special provision and maximizing the 

treatment’s efficiency both in terms 

of performance and cost. Having 

completed the special provision by 

the end of 2014, and publishing it 

in 20161

, PennDOT became one of 

the few State agencies possessing a 

standard provision for HFST. 

PennDOT ramped up their HFST 

implementations to a total of 65 

locations in 2014 and to 150 by the 

end of 2015. The agency’s desire is to 

develop and institute a formal process 

that facilitates and spreads the 

installation of local road HFST projects 

with the State’s Highway Safety 

Improvement Program (HSIP) funds. 

HIGH FRICTION, LONG 

SERVICE LIFE 

In the eight years after PennDOT’s first 

HFST installation, the curve on SR-611 

did not experience any wet pavement 

crashes – which can be attributed 

to HFST’s longevity, durability, and 

resistance-to-polish that provides 

high-friction values over a long service 

life. This pilot location was retreated 

with HFST in 2015 to continue crash 

reductions into the future. 

 1 Pennsylvania Department of Transportation, Publication 408 – Specifications, “Section 659 -- High Friction Surface Treatment,” April 1, 2016 update. Available at: http://www.dot.state. 

pa.us/public/PubsForms/Publications/Pub_408/408_2016/408_2016_IE/408_2016_IE.pdf 

http://safety.fhwa.dot.gov

FHWA-SA-16-056

FOR MORE INFORMATION 

Joseph Cheung Frank Julian Gavin Gray, Chief of Highway Safety 

FHWA Office of Safety FHWA Resource Center Pennsylvania DOT 

joseph.cheung@dot.gov frank.julian@dot.gov GAGRAY@pa.gov