WDEL's Road Scholar: How skid-resistant road surface treatments make travel not as slippery when wet

The resin binder being laid recently on the ramp from DE-273 to northbound Interstate 95 (Courtesy/Rich Palmer/DelDOT)

Some new technology--intended to improve traction and stability around curves--has been recently added to the Delaware Department of Transportation's toolbox.

The introduction--and implementation--of High Friction Surface Treatment (HFST) for a hand-picked selection of roads known for treacherous travel is the state highway authority's answer to enhanced safety--especially in inclement conditions.

Rich Palmer, a DelDOT program manager, recently explained to Road Scholar the process.

"The treatment places a thin layer of specially engineered, durable, high-friction material as a topping onto a firmer setting polymer resin binder--in layman's terms, epoxy."

Palmer revealed how some road surfaces are more pre-disposed to slipperier conditions.

"A really old concrete pavement will have been polished by the tires," he illustrated, "or a brand new asphalt road is very quiet."

As a result, the treatment needs to be added to an existing road surface, not inlaid when the road is constructed or repaved.

"On new pavement it's recommended that we wait 30 days," he explained. "(Until) the oils in the asphalt that are on the surface have dissipated so that you get proper adhesion. On concrete surfaces, we have to actually shot blast the surface to prepare it--to make sure it's clean enough, it's not polished, and that the epoxy will have something to stick to."

By supplying this mix of durable aggregate and epoxy, the skid-resistant effect is achieved--a worthwhile mitigator in areas where the agency has deemed it crucially necessary.

"Eastbound (Route) 273---getting onto northbound I-95-- there's that long sweeping ramp," he reminded. "If anybody has noticed, there's a lot of crash marks along the barrier on that ramp. So that's the first location we did."

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Other locations throughout the state receiving the first round of treatments this fall:

  • New Castle County: Pleasant Hill Road (between Corner Ketch Road and Thompson Station Road), and three other sites
  • Kent County: Mount Friendship Road, near Cheswold
  • Sussex County: nine various accident-prone areas

The contractor secured by DelDOT to perform the work has 180 days to complete the initial 15 areas but--with a three-year open-ended contract--these are just the beginning of a more widespread effort.

"We have a wish list of areas we'd like to have done," Palmer admitted. "We'll be looking at these areas closely and, eventually, we'll be adding on to these (currently scheduled) locations."

The method employed to determine such tracts is analyzing crash data where the combination of wet weather and curves has caused accidents. According to the American Association of State Highway and Transportation Officials (AASHTO), approximately 14 percent of fatal crashes and 25 percent of all crashes occur on wet pavement. These statistics have prompted AAA Mid-Atlantic to endorse the benefits of the technology.

"Additional surface friction along dangerous curves will provide motorists with an extra margin of safety and prevent future crashes, injuries and fatalities," said Jim Lardear, Director of Public and Government Affairs for AAA Mid-Atlantic.

But, of course, even with DelDOT's best laid intentions to curb the occurrence of these collisions on curves, the driver is always the deciding variable.

"All these areas--like the on-ramp to I-95 (from Route 273)," Palmer reiterated, "the posted, suggested speed limit is 25 (mph), and people are doing 55 to 70 on that ramp. They're going way too fast for the conditions, especially when it's wet. If drivers would listen a little bit more to the posted signs, we wouldn't be doing this."

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Contact Andrew Sgroi with Road Scholar story ideas to andrew@dbcmedia.com or follow him on Twitter at @Cuse92.