Better Asphalt No Shortcut to Pothole-Free Roads

A pothole remains open on Selfridge Avenue on Wednesday, March 5, 2014 in Garden City. (Credit: Howard Schnapp)

March 10, 2014 

You might not think so from the potholes you've been hitting, but most experts in the transportation field say the quality of asphalt used on the nation's roads has, in fact, improved dramatically in recent decades.

But that improvement has been offset by more heavy trucks on the road, a lack of regular maintenance to keep roads in good condition, ineffective paving operations and just the insidious nature of potholes.

The Northeast has always had the freeze-thaw cycle in which water seeps into cracks in the road and expands when it freezes, creating the beginning of the pothole. That cycle is exacerbated when the roadway material is subjected to sharp temperatures changes, experts say, such as the 50-degree swing Long Island experienced during the first week of January when the temperature dropped from 55 degrees to near zero in one 24-hour period.

But roads in other parts of the country with warmer climates are often in no better condition. An analysis of federal highway data in 2011 showed that the top 10 large urban areas with the worst ride quality included Los Angeles, San Francisco, Tucson, New Orleans and Oklahoma City.

"Road construction and repair involve a surprisingly complex blend of technology, economics and governmental input," according to Herbert W. Cooper, a member of the American Society of Chemical Engineers and the owner of Dynalytics Corp., a Woodbury consulting firm.

The quality of asphalt has gotten better, according to David Orr, a senior engineer at Cornell University's Local Roads Program, which helps local governments improve their paving capabilities. 

"In the older asphalt mix, we looked at one viscosity grade. Now we have multiple grades for different roads and different areas," Orr said.

Leslie McCarthy, a former federal paving official and now an engineering professor at Villanova University, said having quality asphalt is like having quality ingredients for making a cookie. You still have to bake it properly.

"If [asphalt] comes out of the processing facility at 325 degrees, which is fine, but then there's traffic and it's cooling to 250 degrees, and when you finally dump it into the paver it's 100 degrees cooler than it was supposed to be. That pavement is destined to fail," McCarthy said. 

Laying the blame
Imad L. Al-Qadi, a professor of civil engineering at the University of Illinois at Urbana-Champaign, is among the many experts who blame pavement conditions on the pounding inflicted by increased heavy-truck traffic.

"The most important thing we have seen is the increase in the percentage of trucks using roads and not because the roads are weaker than they used to be," he said. 

Overall traffic on the nation's roads increased by 37 percent between 1990 and 2011, according to a report last October by TRIP, a Washington transportation research group. During the same period, travel by large commercial trucks increased 49 percent, and is projected to increase by about 64 percent by 2030, the group said, citing federal projections.

Numerous reports cite the amount of stress on the roads caused by traffic that is slow-moving or subject to frequent stops, particularly heavy trucks. 

And then there are financial issues. Governments have to weigh whether to spend more to build a better road at a higher cost versus skimping on quality to repave more roads. 

"It's only partly about money," according to Cooper. "It's partly that it takes forever for specifications to be changed to allow something new. There is a fair amount of politics involved. People are entrenched in the current specifications and resistant to change."

The AAA said that while road maintenance can be a complicated topic, motorists should think of it the same way they think of repaving their driveway at home — and money counts for a lot in both projects. 

"It depends on how much you want to spend," spokesman Ed Welsh said. "Six inches of asphalt and it will outlast your house; one inch and roll it and how long do you think that will last?" 

On the government side, money is also a big variable, he said. "The contractor will build to specs [specifications], so government can lower the cost by lowering the specs," Welsh said.

The level of government paving the road can make a difference. Most money for the interstate highway system, created during the Eisenhower presidency, flows to state governments that maintain their interstates. Very little trickles down to counties, towns, cities and villages.

And although most states now follow federal standards for asphalt quality, states pave only 20 percent of America's roads. The other 80 percent is done by counties, towns and other localities, according to the U.S. Department of Transportation. 

Superpave in the mix
An improved surface dubbed Superpave — using a variable mixture of crushed rock (often called aggregate) and bound together with asphalt — was developed with federal funding in the 1990s and most states now use some variation of that mixture on major roads. 

The mix can vary from state to state. "You have to decide what the best additives are for your area — fibers, polymers, lime, injecting water," McCarthy said.

New York State uses a Superpave mixture on all its Long Island projects, a state spokeswoman said, but both Nassau and Suffolk counties say they use traditional paving — a Marshall Mix product for Suffolk and Rut Avoidance Asphalt Concrete type 1A/1A Top for Nassau.

Nassau spokesman Michael Martino said its engineers found that Superpave did not function well at intersections where vehicles stopped for signs or signals.

Superpave costs about $15 to $20 more per ton than conventional asphalt, according to Tom Pratt, vice president of Scatt Materials Asphalt of Deer Park, one of the producers who sells Superpave to the state Department of Transportation.

Alex Gregor, the highway superintendent for the Town of Southampton, said he found Superpave "too brittle" for local roads.

"We use a type-6 top coat, a standard industry mix, and we don't see a reason to change," said Gregor, Long Island regional director of the statewide Association of Town Superintendents of Highways. 

The highways budget for its 880 lane miles of road was $3.5 million when he was elected in 2010, Gregor said, and that is now down to about $1.7 million and it would be even less if there had not been a modest increase in state funding this year. 

"Towns don't want to spend the money," Gregor said. "And there's the 2 percent [state-imposed] spending cap on budget increases."

Gregor said Southampton writes its own bid specifications for asphalt, but Brookhaven, like many other towns and localities, buys off an approved state or county contracting list. 

"We use 51FX mix for hot asphalt. We buy off the Suffolk County bid list," said Dan Losquadro, Brookhaven's superintendent of highways. "Given our budget constraints, we have not even looked at alternatives."

He added: "The budget was $14 million last year. We've identified $80 million to $100 million in work to be done." 

It is difficult to estimate how long an asphalt mix lasts in actual use. The U.S. Department of Transportation and the Transportation Research Board, an arm of the National Academy of Sciences, said recently there has never been a study to determine whether the paving used in recent years has resulted in the same roads lasting longer than they had before advances in paving materials. A 2010 federal Government Accountability Office report said new materials research did not always result in better highways, in part because "35,000 highly decentralized public agencies manage the U.S. highway system, and thousands of private contractors, materials supplies and other organizations provide support services." 

Doing a better job? 

New York State Comptroller Thomas DiNapoli released a report last May that found towns, including those on Long Island, could do a better job of ensuring that the asphalt they were using met bid specifications.

Only two of 10 towns surveyed got a daily batch report from the asphalt plant to ensure compliance with specifications, and only 6 of the 10 required core testing of the finished surface. 

There has been a running debate about whether asphalt or concrete are the best ingredients for a paving surface, but Larry Galehouse, director of the National Center for Pavement Preservation at Michigan State University, said, "We think they're both good in their own way and we don't take sides in that battle," he said.

Iowa has a large percentage of county roads that have a surface coating of Portland cement, according to Orr. "They got in the habit of doing it and got good at it," Orr said. 

Parkways on Long Island were originally built with concrete travel lanes and asphalt shoulders, the state DOT said.

Motor Parkway, which opened in 1908, was one of the nation's first roadways with a concrete surface, the DOT said. As those roads deteriorated over time, they were resurfaced with asphalt in the 1980s and 1990s, the agency said.

A major consideration in using asphalt is that it takes less time to apply, and lanes can be reopened quickly, the state said. 

Conventional thinking was that asphalt lasted longer if applied in a thick coat. But a study published in the International Journal of Pavement Research and Technology last November concluded that the thickness of the top layer of asphalt might not be so important.

Both the cost and the life of a roadway and a pavement are the subject of much debate. The Federal Highway Administration website put the cost of a lane mile in an urban area at between $2.4 million and $6.9 million. In a rural area, the cost varied from $1.6 million to $3.1 million per lane mile, according to the website. 

The search for a better pavement continues. The Paris-based Joint Transport Research Centre examined two possible long-lasting products in a 2007 report — epoxy asphalt and high-performance cementitious materials (HPCM) — and found them "particularly promising." 

The HPCM would require the development of new equipment to install it properly, and long-range testing was needed to achieve the proper balance of mixing and installing it, the report said. 

A huge downside to both materials, the report said, was that "in Western Europe, their costs could be between 2 and 3 times the cost of conventional treatments."

Michael Herman, 72, of Huntington travels Long Island and New York City roads frequently as a salesman, and blames much of his recent $1,200 repair bill for his SUV on wear and tear from potholes.

"It seems incredible to me that the government, both federal and state, can't come up with an asphalt solution," Herman said.

He suggested creating a commission of scientists from outside the industry to recommend a better way of doing things. "Solutions often come from an outside source," Herman said. "And maybe a cash prize should be offered for getting a better asphalt solution."

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