What does it mean that snow accumulations – between at least two and 24 inches – are still found in early March 2014 in 44 of the 48? What about the thick blanket of snow that has been present for months now in a lot of the Northeast and Midwest,&nbsp;<a href="http://www.intellicast.com/Travel/Weather/Snow/Cover.aspx">contiguous American states</a>?

Potholes are on the way, of course. Potholes by the millions, possibly billions, likely. That's because the successive waves of deep cold and snow in the winter of 2013-2014 have set up ideal conditions for potholes to form on the roads, streets and highways. And what's more, the freeze-thaw fluctuations in temperatures that happen in the shoulder seasons (springtime in particular) mean that snow turns to melt water, works its way into pavement cracks, then expands with the freeze that might come just a few hours later.
&nbsp;
This is already become apparent in places like Louisville, Kentucky, where the local news station WHAS-11 has warned drivers about what to do when a car tire blows after hitting a pothole. "The only thing worse than getting a flat tire from a pothole is the thought of changing a flat tire in these temperatures along the side of the highway," said the community reporter for the station. They recommend tire inflator and sealant kits or run-flat tires, which are sufficient to get a car to a service station or warm garage.
&nbsp;
Toward the end of February, the city of Denver, Pennsylvania (Lancaster County) noted that the borough's street salt stock was just about depleted. The public works director there also noted that potholes are currently "full of runoff from the melting snow and can't be repaired until they are drained."
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Most types of asphalt used to fill potholes do not tack to the spot unless it is dry; however, some cold mix asphalt can be set in standing water. Standard asphalt also must be installed while warm from the asphalt plant, which complicates the road repair processes for many municipalities.
&nbsp;
All of which adds up to a bumpy ride across much of the country until warmer, drier conditions allow a better fix a few months down the road.

In Like a Lion: March Snow Cover “Blanket” and Fresh Snowfalls Means Potholes Through Spring

It might seem that the extremes of weather – the "polar vortex" freeze in the U.S. and Canada during the winter of 2014, or the triple-digit temp heat waves in the American southwest regions in recent summers – might cause the most damage to asphalt and pavement. But in fact it is the oscillations above and below 32 degrees F (0 degrees C) that are the primary culprit in creating potholes.

&nbsp;
The science of freeze-thaw cycles and its effects are fairly simple. When water freezes it expands, technically referred to as volumetric expansion. This means that water wants about ten percent more space – 9.87 percent to be exact – when it goes from a liquid to a solid, frozen state. If that liquid water was in a crack or crevasse in pavement, it will push outward and, often, make the crack bigger.
&nbsp;
That alone is bad enough, but in "shoulder season" conditions – any time the weather hovers above or below 32F/0C, usually in October or March, but sometimes in a January thaw or May cold spell – it gets much worse. A freeze on Tuesday means the water pries itself into pavement defects; a thaw on Wednesday translates into more water getting into the pried-open area, followed by another freeze on Thursday that pushes the pavement apart further.
&nbsp;
In most roadways, that freeze-thaw effect gets seriously destructive when water and freezing temperatures reach the sub-pavement, where gravel and soil support the pavement. The expansion-contraction cycles undermine this supporting structure, culminating in a frozen-water bubble that pushes pavement up from below. Once a heavy vehicle passes over such a bubbled-up section of asphalt, the pavement collapses into a bona fide pothole.
&nbsp;
It's a worldwide phenomenon and vexing problem, as engineers in Mongolia document in a paper titled, "Freeze-Thaw Effects on Roadways; Approach to Pavement Design with Special Reference to Roads in Mongolia" (Kachroo, Raju and Gombo). The authors include in their analysis the fact that Mongolia experiences sub-zero temperatures in winter that causes the subsoil to hold its cold temperature until late spring. Thaws, and freeze-thaw cycles, happen to coincide with increased road traffic, a destructive combination for the central Asian country's roads. Traffic in North America increases as well when the weather warms up.
&nbsp;
Drivers who routinely follow a daily commute often report "overnight potholes," a pavement defect that truly does pop up overnight. In fact, it might have been in development for days or weeks, but invisible to humans until the pothole bubble burst from a heavy bus or truck.
&nbsp;
Cities where freeze-thaw cycles are more frequent 
Some parts of the country have more of these cycles than others. The National Institute of Standards and Technology, a bureau of the U.S. Department of Commerce, measured freeze-thaw events for a dozen geographically representative cities in the U.S., identifying the number of cycles each city experiences annually. They are:
&nbsp;
<div class="group">
<div style="width: 40%; padding: 0 10pt 0 0; float: left;">
City
Kansas City, MO 
Tampa, FL 
Lubbock, TX 
Tucson, AZ 
Cheyenne, WY 
Pierre, SD 
Seattle, WA 
Fresno, CA 
Baltimore, MD 
Bridgeport, CT 
Alpena, MI 
Waterloo, IA
</div>
<div style="width: 40%; padding: 0 10pt 0 0; float: left;">
Freeze-thaw cycles per year
79 
0 
61 
9 
126 
92 
25 
14 
83 
90 
102 
72
</div>
</div>
&nbsp;
In its own study, the National Ready Mixed Concrete Association reported in 2004 the number of freeze-thaw cycles for other cities:
<div class="group">
<div style="width: 40%; padding: 0 10pt 0 0; float: left;">
City
Asheville, NC 
State College, PA 
Athens, TN 
Chattanooga, TN 
Chapel Hill, NC 
Gallup, NM 
Roswell, GA 
Salt Lake City, UT
</div>
<div style="width: 40%; padding: 0 10pt 0 0; float: left;">
Freeze-thaw cycles per year
90 
120 
90 
50 
90 
210 
50 
90
</div>
</div>
What both sources point out is that the degree of moisture is another factor, where some regions have wetter climates than others. But that said, places such as Gallup, New Mexico clearly have more freeze-thaw challenges than Tampa or Tucson.
And to be clear, factors other than freeze-thaw cycles contribute to pothole development. Those include extreme heat (pavement sometimes explodes when trapped, sub-pavement water is converted to steam), heavy traffic, poor maintenance and time. This is why places that include Tucson, Tampa, Honolulu, Miami and Los Angeles all experience crumbling roads – no polar vortexes required.

How has the “Polar Vortex” affected your roads?

Hurricane Sandy's massively damaged the infrastructure in NY, NJ, NC, CT and RI. Rapid repair of roads, bridges, water and sewer systems will reduce net costs.
&nbsp;
The images from Hurricane Sandy's wrath in northeastern U.S. states include many of streets inundated with water as well as beachfront highways completely destroyed by storm surges. The loss of life, with nearly 100 storm-related deaths reported and the full tally not yet known (as of 11/2/12), as well as human suffering amongst family and communities where entire neighborhoods were destroyed, is of course of utmost concern. But in the clean up, we can expect to see many streets, roads and highways that are rendered unpassable and consequently will need to be rebuilt.
&nbsp;

Within the days following the hurricane, the U.S. Department of Transportation announced it is releasing $29 million in emergency funds to repair roads. This money is divided according to assessed need per state: New York and New Jersey receive the largest amounts, $10 million each, while $4 million goes to North Carolina, $3 million to Rhode Island, and $2 million to Connecticut.
&nbsp;
"These emergency relief funds represent only the start of our commitment to the region's recovery," said Transportation Secretary Ray LaHood. "We need to do all we can to help communities get their transportation systems up and running."
&nbsp;
Reports from the local media in affected areas provides a closer look at where some of these dollars will be needed most:
&nbsp;
Long Beach Island, New Jersey – The Star-Ledger's nj.com surveyed destruction in this vacation destination, noting "some roads in waist-high sand after the storm surge completely pushed over the barrier island to the bay side. Hundreds of beach houses there are designed to allow the first floor to break away in such a surge, which left the top half of those houses still standing on stilts. Bulldozers have been recruited to clear the sand from those highways and streets.
&nbsp;
Rodanthe, North Carolina – The Charlotte News-Observer ran dramatic photos of North Carolina Highway 12 (NC-12), a state highway and popular tourist route that traverses the shoreline of the northeastern part of the state, which show the <a href="http://www.charlotteobserver.com/2012/11/14/3665319/sea-and-sand-close-nc-12-again.html">asphalt road practically slipping into the sea</a>. Large, long cracks suggest the sandy foundation of the road was undermined by strong storm surges.
&nbsp;
New York State – EmpireStateNews.net reports that state comptroller Thomas P. DiNapoli is projecting a net cost of $18 billion to rebuilding New York State infrastructure, including highways, power, water and sewer systems. DiNapoli bases these numbers on previous natural disasters and cautions this may be an underestimation. The news website adds, "Rapid remediation would reduce damage from the corrosive effects of water, pollutants and other factors," to which DiNapoli responds, "The sooner we get contractors on the ground to assist residents and business owners, the faster New York will be back on its feet."
&nbsp;
The presence of so much moisture just before winter weather sets in suggests additional problems for pavement quality. Water, asphalt cracks and freeze-thaw cycles generally result in potholes and other forms of road deterioration. This might be exaggerated where the subsoil has shifted due to extreme flooding. Coastal areas, for obvious reasons, are likely to be the most affected.
&nbsp;
The $29 million in federal funds are not likely to be the total. The New York Times reports that the federal government ultimately paid out $120 billion in the aftermath of hurricanes Katrina and Rita in 2005 for all emergency and long-term losses and infrastructure repairs.

Hurricane Sandy's Effects on Atlantic Seaboard Roads, Pavement Widespread

The Weather Channel predicted above-average warmth for the Southwest, Midwest, Great Lakes and Northeast back in April (of 2012). The fact that highway pavement is buckling in all those places from heat – already in June – is proving that forecast to be on the money.
That's because scorching summertime temperatures in the 90s and 100s (Fahrenheit – in Celsius that's about 32 to 38 degrees C and higher) have come early to each of these regions. Already by mid-June, municipalities from Oklahoma to Pennsylvania began dealing with sudden roadway eruptions, caused when the expansion of concrete pavement under extreme temperatures forces sections to buckle. When the first heavy vehicle rolls over those buckles, the pavement crumbles and you get the summer version of a pothole. Asphalt pavement offers a different phenomenon, that of trapped water in sublayers under pavement. Under extreme heat conditions, trapped moisture that cooks under the roadway can literally explode – quite like steam blowing the lid off a pressure cooker.
One of the first example of heat-induced potholes is from north of the border, in Toronto. The temperatures cracked 34C (that's 93F) already on June 21, the highest such reading on that date in 60 years. To Texans who endured 40 straight days of 100-degreeF (38C) and higher temperatures in the summer of 2011, that may seem like a reprieve. But when your 'Leafs are only a few weeks off the ice, it's pretty tough on the people and their cars. The Toronto Star <a href="http://www.thestar.com/news/article/1215278--toronto-breaks-temperature-records-hwy-401-buckles-under-the-heat">reported</a> that two lanes on the 401 at Avenue Road were closed that afternoon when a 30-centimeter (11 inches) section had buckled up. It took the Ministry of Transportation two hours to "grind down the heaved highway," according to the paper.
But most of the action is happening south, where the heat wave is currently concentrated. Here is a roundup of reports in the Midwest and East:
Iowa – The state Department of Transportation issued a warning published in the Quad City Times back in July 2011, explaining that a combination of wet weather alternating with heat are the combination that leads to asphalt blow ups. This year, the Spencer Daily Reporter in Clay County, Iowa reported exploding asphalt already in mid-June.
Michigan – The problems with heat affected some very serious and experienced drivers at the Michigan International Speedway. The <a href="http://www.toledoblade.com/sports/2012/06/19/Heat-roof-of-problem-for-blistering-tires.html">Toledo Blade</a> interviewed Dale Earnhardt, Jr. who shared sentiments with other NASCAR drivers in the Quicken Loans 400 on June 17. The racing organization required tire changes at mid-race, which drivers resisted although it did allow them to assess the shape of their tire tread. They found blistering, due to both road temperatures and new pavement, which enabled faster speeds. Earnhardt told Speed Channel TV his tires felt "like they were six years old. This ain't cool."
Missouri – The CBS-TV affiliate in St. Louis reported that a MoDOT (Missouri Department of Transportation) maintenance engineer says it's difficult to predict where pavement blowups will happen in advance. The news show cites such road deterioration events as a "dangerous problem."
Oklahoma – In Romona, a small town in Washington County in the northeast corner of the state, concrete was reported to be buckling on June 26. According to KJRH-TV, damage to sections of US 75 required several days of repair work. The state DOT spokesperson explained, "concrete moves and expands. This area near Romona happened at a joint." A lot was learned in the heat waves of 2011, the reporter explained.
Pennsylvania – A PennDOT spokesperson told the Montgomery County <a href="http://www.timesherald.com/article/20120621/NEWS01/120629880/heat-causes-section-of-rt-422-to-buckle">Times-Herald</a> that portions of Route 422 buckled on June 20, forcing emergency repairs and lane closures. He explained these pavement breakdowns are "not terribly unusual on older concrete beds where you have days of 90-degree temps."
Wisconsin – The Fox-TV affiliate in Wausau reports that "authorities across central Wisconsin are receiving reports about pavement buckling on roads and highways due to high temperatures." In one case, both US 10 westbound lanes in Portage County were closed for repairs on June 9. Local roads in Marathon County were also affected by pavement buckling and required repair work.
So how will the temperatures – and roads – fare as the summer wears on? The Weather Channel says "Get ready for a hot summer from the Desert Southwest into the nation's heartland." In June-August 2012, we should expect "the most above-average warmth to focus from the nation's CornBelt to the southern Rockies and Desert Southwest. Above-average warmth is also expected into the Great Lakes and Northeast." The Southeast (including Florida) and the West Coast should expect cooler than average summer weather.
That may be good news for motorists in Alabama, Florida and Georgia. But for those who live in heat-affected regions, buckle-up: Buckling concrete and exploding asphalt may be in store.

Early Summer Heat Wave Buckling Pavement

The mild winter of 2011-2012 is proving to be a windfall for state, city and county transportation departments. With less snow and ice to remove, that's less plowing and salt spreading than in previous winters. Fewer days of plowing means less gas consumption and work crew overtime, and less salt to purchase as well. To municipalities of even a modest size, that can translate to tens of thousands of dollars saved.
The weather conditions also mean that fewer potholes will form. But will the money saved go to fixing the potholes that are already there?
National Public Radio reported in early February that there are multiple positive economic effects from the milder winter. Private construction projects are proceeding in places where temperatures and precipitation might otherwise preclude such economy-boosting factors from happening. Retail and restaurant traffic is up – it's more likely that people will shop and go out when the roads are dry and the temperatures tolerable.
An NPR reporter interviewed Scott Bernhardt, whose firm <a href="http://www.planalytics.com/">Planalytics</a> (based in Berwyn, Pennsylvania) looks at how weather affects economics, industry and consumer behavior. He explained that "local governments are saving tens of thousands of dollars because the snowplows and salt trucks are in dry dock," according to the NPR report, which noted how 42 percent of the U.S. had snow cover in January 2011, but less than 13 percent of the country was under snow one year later, in January 2012.
Potholes are not absolutely tied to winter weather, of course. Pavement deterioration is a function of one, several or all of the following: moisture, freeze-thaw cycles, traffic loads and time, meaning that potholes can happen anywhere (some of the worst-rated roads in the U.S. are in Los Angeles and Honolulu, illustrating the point). But certainly, snow that falls on a 29-degree (F) day, packed into ice by moving vehicles will become water that gets into pavement cracks a few hours or days later when the temperatures rise just a few degrees. As trucks and cars roll across those cracks, the water is pushed deeper into the sub-pavement, where it might refreeze overnight and further undermine stressed asphalt. In a relatively short period of time, potholes appear.
Will dollars saved be used to repair potholes?
Many local municipalities are consequently reporting leftover cash from lower-than-budgeted use of snowplows and salt trucks this winter, and some are already talking about using the funds for infrastructure remediation. Some examples:
<ul>
<li>The Hazeldon, Pennsylvania <a href="http://www.timesleader.com/hazletontimes/news/Mild_winter_depends_on__lsquo_weather_rsquo__or_not_you_like_snow_02-03-2012.html">StandardSpeaker.com</a> reported in January that Hazeldon city crews are out fixing potholes, something they typically would not be doing until spring, when temperatures are more accommodating to hot asphalt mix (which cannot be applied in cold temperatures). The city had overspent its budget by $100,000 in 2007 when a massive snowstorm required hiring in outside snow removal contractors.</li>
</ul>
<ul>
<li>Le Mars, Iowa, the seat of Plymouth County, the savings in December alone from having no snow removal was between $50,000 and $60,000, about 15 percent of the secondary road budget. "Fuel usage is about half or 60 percent of what it is when they are plowing snow," said Tom Rohe, county engineer, to the <a href="http://www.lemarssentinel.com/story/1802474.html">Le Mars Sentinel</a>. "We're not running 14 trucks on a route right now so our truck usage and fuel usage is quite a bit less." Rohe said that if the favorable mild winter weather continues, they will be able to replace bridges and repair pavement in 2012.</li>
</ul>
<ul>
<li>Buffalo, New York, the seat of Erie County and regarded by many television meteorologists as the snow capital of the east, has seen significant savings in this season. While the ski resorts in the southern tier of the state, a mere hour's drive south of Buffalo, are suffering, the county has thus far chalked up savings to the tune of $550,000 in salt, $120,000 in truck fuel and $150,000 in (budgeted) overtime pay. The nearby suburb of Amherst, home to the State University of New York Buffalo campus, expects to save about a half-million dollars if weather trends continue, reports the <a href="http://www.buffalonews.com/topics/winter_2011-12/article716309.ece">Buffalo News</a>.</li>
</ul>
Regardless of location and even the cause of pavement potholes, delayed repairs have a multiplier effect on costs. By some estimates, every dollar not spent on repairs turns into seven dollars of cost in five years time. Road engineers and directors of departments of transportation understand this all too well, but recessionary times have meant more delays in crack sealing, pothole repairs and asphalt top-coating – putting off until the future the repairs that should be undertaken now.
With this winter's reprieve from snow plowing and salt use, perhaps more of those pavement repairs will be made on a timely basis.

Can Warm Winter Snowplow Savings Fix Potholes?

The La Nina weather pattern is in force in the Pacific Ocean off Chile, and that means less snow in the New York-New Jersey-Connecticut tri-state region. At least, that’s what the National Weather Service is predicting – a forecast that more or less concurs with the Old Farmer’s Almanac, which makes its predictions based on sunspots, tidal waves and astrological positions. Says the Almanac: “Colder than normal winter temperatures” will prevail, but snowfall slightly below average.
But the question on the minds of all – once you get past the discomfort and inconvenience of freeze-your-hair-off winds and rush-hour blizzard conditions – is what will happen with the potholes. Will the exit ramps off the Major Deegan Expressway inflict mortal damage to your wheel rims come March? When borough traversing on the Cross Bronx Expressway, will you need to summon your inner NASCAR skills to avoid the chuckholes that otherwise spell doom to your axel? Will it be worse traveling in Westchester County than, say the Merritt Parkway in CT or I-78 in, around or through Newark?

Time will tell, but there’s plenty to be worried about. Think back to the middle of May 2010, when the Metropolitan Transit Authority bridge and tunnel division announced they were changing all pothole repairs and highway sign maintenance to the graveyard shift, 11 p.m. to 7 a.m. That agency was working on closing a $400 million budget shortfall – a problem facing highway maintenance departments from sea to shining sea in America – and make no mistake, this was more about savings than it was traffic improvement. But now, instead of paying crews overtime to fix the potholes at night, they are working at regular wages.
Said MTA chief Jay Walder, there “isn’t anything the drivers will notice, unless in a good way, because we’re doing things at times when it’s less disruptive to them.”
Better pothole filling technologies
Walder has more tools to accomplish that than did his predecessors ten or more years ago.
The world of road paving and maintenance has improved considerably since the 1990s, due to a federally funded initiative called the Strategic Highway Research Program (SHRP). The program looked at new techniques and technologies that can address problems that are becoming more prevalent in the country’s aging infrastructure (given how massive road building projects under Robert Moses and the Eisenhower Administration happened 50 or more years ago).
SHRP research, conducted through both universities and private companies, studied the intrinsic nature of traffic, weather, asphalt, concrete and how local and state maintenance and safety programs were run. From this research, more than 100 new products were developed and shared with public highway maintenance entities.
What does this have to do with potholes in Passaic? Plenty. One of the breakthroughs of the research was the Superpave program (the name is trademarked), which breaks down into three parts:
<ul>
<li>Asphalt binder specifications that account for installation logistics as much as longevity.</li>
</ul>
<ul>
<li>A design and analysis system, based on the volumetric properties of an asphalt mix.</li>
</ul>
<ul>
<li>Models for mix-analysis tests and performance prediction (i.e., knowing better how to adapt the asphalt formulation to specific roads)</li>
</ul>
Most important in the full breadth of SHRP research was designing pavement to fit variables in climate and traffic conditions. After all, a pretty but less-traveled road through the Poconos is going to experience different wear-and-tear than the Long Island Expressway, just as that highway is different from, say, any road in Arizona.
When it comes to asphalt installation and longevity, a breakthrough was the development of premium cold mix. Typically, asphalt is heated in a plant to give the petroleum-aggregate stone mix elasticity, enabling the mix to form to cracks and potholes in the road. The problem is that hot mix cools off within a few hours, especially in winter, such that a truckload of hot mix might need to return to the plant for expensive reprocessing in order to get it sufficiently warm enough to use. With cold mix, the product can be stored on highway property for months and used on an as-needed basis.
Good cold and bad cold (asphalt mix, not weather)
Note, there are different grades of cold mix asphalt. Lower grades tend to be used in emergencies, when a hole emerges overnight and needs to be fixed to enable a smoother morning rush hour. Unfortunately, that pothole patch might last about as long as it takes to drive from the Upper East Side to Montauk on a cold afternoon in January.
Premium grade (example: EZ Street Cold Asphalt) is another story. It costs a bit more than both hot mix and lower-grade cold mix asphalt, but the savings result in several important ways. First, crews can work from stockpiles, eliminating time-consuming trips to asphalt plants every few hours. More importantly, the longevity of the asphalt reduces the need for repeated repair of the same potholes in a single season, while fewer lawsuits result from motor accidents caused by poorly tended highway. Drivers too benefit when potholes and utility cuts are smoothed over by premium quality cold mix, because traffic flows more smoothly and they suffer less damage to their vehicles from pothole hits.
Of course, all of this is still dependent on budget. TodaysTrucking.com gave a callout to New Jersey as a good example of low administrative costs ($63,000 per mile) associated with state road maintenance expenses, as compared to California’s $100,000 per mile in administration costs. But those are about just the overhead. The real number of concern is how New Jersey spends $1.1 million each year per mile of state highway (California’s is $545,000 per mile). The difference is in part climate related, even though California is just as susceptible to pothole formation due to moisture and heat.
So will the departments of transportation in New York, Newark, East Orange, New Rochelle, White Plains, Commack, Greenwich and Norwalk fight the winter pothole season with a Superpave, premium cold mix strategy? Time will tell. But given the constrained budgetary conditions of each state and municipality, reflecting the cutbacks motorists and companies are experiencing, a smarter pavement maintenance program seems like a good offensive move against winter weather – regardless if the Old Farmer’s Almanac is right or wrong.

WINTER 2011 – EXTRAORDINARY POTHOLES

The reworking of the U.S. weather maps in early January reflects what most of the northern tier of the United States has quietly been happy about: This winter hasn’t turned out to be nearly as bad as expected. That might result in smoother driving next summer, from less damage to streets and highways, and more money to fix potholes because snow and ice removal have not been necessary.
There are, however, many “ifs” to this story.
The winter predictions as of October 2011 had been almost dire: Colder and snowier than normal weather in the upper Midwest (Nebraska through western New York) had been forecasted by AccuWeather.com. But as of the second week in January, the following temperatures were posted for cities in that region: Chicago (46 degrees F), Buffalo (40 degrees), St. Louis (53 degrees), Omaha (49 degrees), Minneapolis (49 degrees), Milwaukee (47 degrees), Kansas City (52 degrees), Amarillo, Texas (48 degrees), Nashville (49 degrees), Detroit (45 degrees), Indianapolis (49 degrees) and Des Moines (50 degrees). In each of these cities, there was not a snowflake in sight. On most days, sunshine prevailed as well.
In case you do not live in this region, you should know this much: such temperatures in January are considered “balmy.”
If anything, the concern is about dry weather, where a lack of snowmelt in the spring might lead to drought-like conditions next summer. Time magazine reports that “at the end of 2011, less than 20 percent of the continental U.S. was covered with snow, compared to more than 50% at the end of 2010.”
This turnabout in weather patterns can have a significant impact on pavement. In a typical winter, the onslaught of snow, ice, freeze-thaw cycles, road salt and snow plows leads to the second portion of each calendar year: Pothole Season. It’s an annual race against physics and forecasts for northern-tier cities’ departments of street maintenance: fill potholes as they open up during winter with a temporary, lower-quality cold patch material, then return in the spring and summer with a more permanent roadway fix of higher quality hot asphalt (which doesn’t work in freezing and wet conditions).
Winter conditions aren’t the only thing that can cause pavement to deteriorate. In fact, potholes are often just as common in the tropics and semi-tropics, places where the thermometer almost never dips below 32 degrees F (0 degrees C).
Road quality in Hawaii and California ranks with the bottom five states (along with New York, Alaska and Rhode Island) of a national survey conducted by <a href="http://reason.org/news/show/19th-annual-highway-report">Reason.org</a>. The roads with the best conditions (judged on the basis of state highway systems) are Nebraska, New Mexico, Kansas, Montana and North Dakota. These numbers strongly suggest that pavement deterioration (i.e., potholes) are a function of something other than just winter weather.
In fact, a combination of moisture, traffic and time can deteriorate a road pretty effectively. It’s just that icy temperatures – especially when they oscillate above and below 32 degrees F (0 degrees C), allow water and ice to pry open roadway cracks – plus salt and snow plows, are what add to the damage. The CBC News in Canada reported from Regina, Saskatchewan in early January that the normally ice-bound city is experiencing just such oscillations in this mild winter, such that they expect a greater number of potholes than normal.
&#8220;During the day the ice melted, and the melted water was going through the cracks, and at night it freezes and pushes back,&#8221; Nigora Yulyakshieva, the City of Regina&#8217;s manager of roadways preservation, told the news service. She explained that roads in Saskatchewan are built to withstand colder weather, so they are not able to handle the freeze-thaw cycle as well as cities with warmer climates.
&#8220;We don&#8217;t notice it yet, but what will happen in the spring is we will see more potholes and bumps if temperatures stay as they are,&#8221; she said.
As Yulyakshieva suggests, municipalities further south that are experiencing a mild winter are likely to see fewer potholes if these weather conditions persist (a big if that is – AccuWeather says that temperatures and precipitation could well return to normal conditions in February and March).
The creeping dilemma of deteriorating roads, streets and highways
The unfortunate news is that the roads were in bad shape to begin with. A mild winter does not make the old potholes go away.
The single largest contributor to the pothole problem in the U.S. and many other regions of the developed world is simply time: roads built in the three decades following World War II are now more than 50 years old. Local, state and federal highway maintenance departments have learned a lot over these years, including how to manage small pavement cracks before they grow into crevasses and potholes.
But the system is so large that routine maintenance has been judged to be expensive. Some of that has been penny-wise-dollar-foolish thinking, as deferred maintenance can increase the cost by as much as a factor of seven (to illustrate, think about cracks and cuts in pavement that instead are left unsealed, then add water to those pavement breaks just before the temperatures dip below freezing, winter upon winter, for several years – a process some refer to as “frost wedging”).
The truth is we’re not keeping up with those cracks. The American Association of State Highway and Transportation Officials (AASHTO) states that spending nationally on road and highway maintenance should be around $166 billion per year, but in recent years – even with the infusion of 2009 and 2010 federal economic stimulus funds – that number peaked around $114 billion. Outside of stimulus dollars, only about $78 billion is spent in other years. Adding to the problem, federal gas taxes (18.4 cents per gallon) that make up the Highway Trust Fund (HTF) are declining as vehicle fuel efficiency increases. Just at the time when the money is needed, more than ever, repair revenues are down.
Hold the salt, pass the asphalt?
Factoring into streets and highway maintenance is how money is not being spent this mild winter. The Associated Press reported in late December, “the mild weather has been a boon for cash-strapped cities that have hardly touched their salt supplies or snow-removal budgets.”  Bloomington, Illinois public works director Jim Karch says he’s spent only $8,000 of a $325,000 winter labor budget thus far. In Normal, Illinois, the current expenditures of $2,100 compare to $140,000 spent by the same date one year earlier. The snowfall in Chicago (1.7 inches by the end of December, compared to the average 8.7 inches) means that only $500,000 in snow removal was spent in December as compared to $6 million in December of 2010 – with $19,500,000 remaining in the winter budget.
So, we should count our blessings that a milder winter might mean fewer new potholes in 2012 (unless, as in Regina, the temperature fluctuations around the freezing point meet up with the presence of moisture)? Or might it be smarter to just shut up about it lest we jinx our good fortune?
Perhaps by March or April, we’ll hear that the dollars saved on snow removal and salt is being channeled to street repairs. Until then, our lips are zipped and our fingers crossed.

Milder Winter, Fewer Potholes?

As winter settles in, it is anyone’s guess as to whether the weather will meet expectations. But as sure as there will be cold, snow, sleet and eventually, a thaw, there is one prediction that is a safe bet: there will be potholes.
A severe period of cold and snow is predicted for the upper Midwest, including storms expected to hit Chicago, Indianapolis, Omaha, Nebraska and of course Buffalo, New York. AccuWeather.com predicted in October 2011 that in terms of temperatures, Minneapolis will get the “worst of winter’s cold alone.” The meteorological site further predicts, “bitterly cold blasts of arctic air are expected to invade the northern Plains, Midwest and Great Lakes in December through January.”

Texas, fresh off a drought-and-heat ridden summer – sometimes characterized by exploding pavement, where moisture under pavement turned to steam, quite like a pressure cooker – is expecting that “winter temperatures will be milder than normal, on average, with much-below-normal rainfall,” according to the Old Farmer’s Almanac. “The coldest periods will occur in early and mid-December, early January, and early February.”
Arkansas is expecting drier, warmer temps than normal. Just north, in Missouri, the Almanac predicts warmer and drier weather as well in winter, but a cooler, wetter spring.
AccuWeather.com’s long range expert, Joe Bastardi, is predicting “severe bouts of cold deep into Texas and Florida [that] would be capable of affecting agriculture more so than we’ve seen in the last 20 years.” He predicts this based on a combination of strong El Nino and La Nina cycles and arctic volcanic activity, such as the Icelandic volcanoes (Eyjafjallajokull in 2010, Grimsvotn in 2011 and possibly an eruption of Mighty Katla in 2012) which severely impacted air traffic in Europe in 2010-2011 and could affect global temperatures in the year or two following 2012.
The freeze-thaw heave-hos – and truck traffic
Severe weather is one thing. No one likes shivering while waiting for their car to warm up, it’s never fun to drive in icy conditions, and no one wants to get stranded in their vehicles in a snowstorm. But the real problem, insofar as potholes go, is temperature fluctuations. Added to traffic and the simple passage of time, the dance above and below the point where water freezes is what rips pavement apart.
It is not at all unusual for most regions of the country – except those that are in the sub-tropics, where freezing temperatures rarely occur – to have frequent temperature variances above and below 32 degrees Fahrenheit (0 degrees Celsius) during certain seasons of the year. This is the point where water turns to ice, of course, which causes an expansion of cracks and crevices in a roadway, followed by erosion when the ice melts, and later more expansion the next time temperatures again drop below 32 degrees. A small crack can turn into a gaping pothole in a matter of days when such conditions are right.
Exacerbating all that is traffic, as heavy vehicles roll over those small gaps in space. The pressing action of cars and trucks – especially the trucks, which weigh as much as 19,000 pounds per axel, several times more than on passenger vehicles – squeezes sub-pavement water outward. In so doing, the freeze-thaw phenomenon is spread over a larger area.
Which gets to the dilemma of roads and trucks and pavement quality: our economy depends on trucks, and trucks depend on good roads. Truck delivery is intrinsic to commerce – from ports and freight train intermodal transfer sites to retailers, manufacturers, commercial buildings and residences. When pavement is in poor condition, trucks incur damage (flat tires, broken axels – and accidents) or at least are forced to drive slower. Potholes literally slow the wheels of commerce, adding time and expense to trucking operations and those businesses that depend on them.
There are more than 3.2 million people employed as short-haul and long-haul truck drivers in the U.S., with about 15.5 million trucks in operation, about two million of which are tractor trailers (the biggest vehicles). In any given year, trucks log more than 430 billion miles on U.S. roads, streets and highways. Freight trains might be cheaper and able to move goods at lower energy costs, but they are slower and more cumbersome. In the United States, moving goods by surface vehicles (trucks on roads) commands 88 percent of all shipping dollars. This reflects a trend away from rail shipping that began with the construction of the interstate highway system in the middle of the 20th century.
Truck traffic somewhat correlates with denser population, such as is seen around cities like Miami, Fort Lauderdale, Tampa-St. Petersburg and Jacksonville, Florida. Statewide, the average annual daily traffic (AADT) actually increases at a greater rate than the increase in population in rural counties, as those counties’ interstate highways are main corridors of transportation between population centers (source: Florida Department of Transportation, Project Traffic Forecasting Handbook, October 2002).
In other words, traffic is spread evenly throughout the interstate highway system, somewhat apart from where the population centers are. Secondary highways, roads and streets of course get much more traffic in the urban areas, leading to significant pavement deterioration from vehicular traffic in combination with weather conditions. The same can be said in crossroads/manufacturing states such as Texas, Arkansas, Missouri, and Illinois and throughout the country.
Pothole blitz worked in Virginia
In the springs of 2010 and 2011, the Virginia Department of Transportation (VDOT) approached its own roadway pothole problem with a “pothole blitz.”
According to a press statement from the state’s governor, Bob McDonnell, &#8220;Virginia&#8217;s transportation network is vital to our economic prosperity and connects people to their work, homes, families and friends. Although the milder winter we experienced this year has led to fewer potholes to repair than the 161,00 filled during our 2010 pothole blitz, VDOT and its contractors promptly responded when Virginia citizens reported potholes to VDOT&#8217;s website or called their customer service center. The pothole blitz has helped to make travel safer and easier for all Virginia motorists.&#8221;
The repairs were made to state-maintained roads and interstates. It was driven by a public education campaign, asking residents to report potholes by way of VDOT, which then conducted a triage of sorts in determining where to fix roads first. Severe potholes in highly trafficked areas were given priority, fixed within 24 hours of reporting.
In online news stories about the Virginia blitz, the commenting readers complained that these potholes were given temporary filler. (Temporary repairs with lower-quality cold mix asphalt are often necessary in colder conditions, however higher-quality, permanent-fix cold mix asphalt is in increasing use by many municipalities.) The state responded by saying that reconstruction or more resilient, permanent repaving constituted the second part of this program, repairs that commenced once the freeze-thaw season had passed.

Winter 2011-2012 in the Central U.S. – and the Potholes to Come

The record level of snowfall along the eastern corridor at the end of October 2011 caused enough damage on its own. Millions of homes and businesses went without electrical power as a result of downed power lines. As fall turns into winter, we’re reminded that where nature intersects with civilization, man-made things have a tendency to fall apart.
This snowstorm did the region the disfavor of arriving while the leaves where still on the trees. Those leaves caught more of the wet snow, which then burdened branches that broke and fell on electrical power lines. The lines broke and power was cut off on a massive scale: 830,000 customers in Connecticut were out at the peak, as were 483,000 in Massachusetts, 380,000 in New Jersey and 300,000 in New York State. In Maine, 160,000 customers lacked electricity, as did 315,000 in New Hampshire, 43,000 in Maryland, 200,000 in Pennsylvania, 20,000 in Rhode Island and 7,500 in Vermont.

The early arrival of winter was due to an easily understood Nor’easter, where a mix of warm ocean met up with an eastward-moving cold front. It all arrived just a little earlier this year. There were warnings earlier in the week, when the same weather system pulled temperatures down in Colorado from 82 degrees (F) on Monday to 32 degrees by Wednesday. Temps weren’t quite so low as the system just dumped rain on the Mississippi Valley region (Chicago and St. Louis in particular). But when it reached the mid-Atlantic coast and off the coast of New England, the cold air mixed with the moisture to circle back over land – leading to as much as a 32-inch snowfall in parts of Massachusetts. In New York City’s Central Park, the first-ever snowfall of one inch-plus in October was recorded.
All of this is just a clear reminder that snow will come, as will cold temperatures. Power lines will continue to fall in ice storms and heavy snow. But what is particularly damaging to roads – what causes potholes – are two factors: moisture (precipitation) and temperature fluctuation, above and below the freezing point (the freeze-thaw cycle).
Those cycles typically happen in February, March and April in much of the country. In coastal areas such as eastern Massachusetts, Connecticut, Rhode Island and New York, those oscillations can be more frequent in those months. But in freak storms such as this, it can happen in the fall as well.
Drivers need to be cautious about icy patches and bridge roads that freeze before pavement on solid ground. And, they should add to that to look out for seasonal potholes as well.

October Snowstorm an Early Warning – About Potholes

For U.S. motorists in any parts of the million-square-mile area under the heat dome of 2011 – with temperatures in the 90s and 100s (Fahrenheit), and heat indices 20 and 30 points higher in some places – there's more to worry about than engine coolant and functioning air conditioners. Add exploding potholes to the list.
Actually, it's pavement that is exploding, leaving potholes in its wake. This largely occurs with asphalt roads. Where concrete slabs are used in highway construction, the danger is buckling, as when one-ton chunks of concrete push upward due to the expansion effect of heat, creating dangerous steps and ramps in the roads.

Cable network CNN reports there are 141 million people living in the areas affected by the heat wave, which stretches from southeastern California and Arizona, across Texas and the Gulf states, up across the eastern seaboard to New York and Boston, as well as through the Plains states on up through the Dakotas, Wisconsin, Illinois and Michigan. Triple digit temperatures were felt on Wednesday, July 20 in Las Vegas, Phoenix, Blythe (California), Wichita, Topeka and Lawrence (Kansas), Wichita Falls (Texas), Omaha, Oklahoma City, Tulsa, Fort Smith (Arkansas), Columbia (South Carolina) and Chicago. Cities edging close to that with temperatures in the high 90s were St. Louis (99 degrees), Kansas City (96 degrees), Dallas (96 degrees), Detroit (95 degrees) and Minneapolis (96 degrees).
In Iowa, the cities of Cedar Rapids (97 degrees), Des Moines (97 degrees) and Waterloo (97 degrees) are just about as bad off as in neighboring states. But high temperatures did not slow intrepid news reporters in those cities, as well as Chicago and Minneapolis, from identifying the phenomenon of exploding and buckling pavement. Culled from the media in several cities we see the following:
From the Quad Cities Times: "Drivers traveling in Iowa should be aware that the mercury might not be the only thing to rise during the sweltering summer heat. Pavement blowups occur when thermal expansion forces the pavement to buckle and shatter. A number of such incidents have been occurring this week. 'The wet weather in parts of the state combined with the extreme heat is a recipe for pavement blow ups,' says John Selmer, director of the Iowa Department of Transportation's (DOT) Statewide Operations Bureau."
From the Des Moines Register: "Extreme heat caused road buckling at the intersection of First Street and Ankeny Boulevard on Tuesday. City officials have temporarily fixed the problems to keep traffic moving. Heat pushed up the concrete and part of a steel storm sewer grate. A cold patch was applied to the hole. In eastern Iowa, repairs are underway on a stretch of Interstate 380 after sizzling temperatures caused the pavement to buckle. The 'blowup' happened Monday night in the northbound lanes about a mile south of the Swisher exit, between Iowa City and Cedar Rapids."
But this is nothing new, not even for the Summer of 2011. Already in early June, pavement problems due to heat were reported in Watertown, Wisconsin.
From the Watertown Daily Times: "The high-rising temperatures Tuesday caused several area roads to buckle and blow up. High temperature records were set throughout the state Tuesday as Watertown recorded a high of 94 and in Milwaukee the mercury reached 97 degrees. When the temperatures rise, such as they did on Tuesday, highway concrete expands, according to Randy Franks, supervisor at the Dodge County Highway Department. When there is no place to go the concrete cracks and blows up, he said."
Watertown's street superintendent Rick Schultz explains that crews use a milling machine and skid steer to grind cracking pavement, sometimes completely repairing joints underneath the road. When they need to mill down to the sub-base of an asphalt road, the section of pavement is cut out completely and reconstructed. Seal coating, itself a method used to preserve aging pavement, sometimes "bleeds" under very hot conditions, which is then addressed with aglime (crushed limestone or dolomite) to stem loss of the seal.
From CBS affiliate WCCO-TV (Minneapolis): Sections of I-94 in the Twin Cities area were closed due buckling pavement.
From WBBM-TV (Chicago): The station is warning viewers that portions of Lake Shore Drive buckled in 2010, when temperatures were not as high. "[Concrete] pavement buckling is different from a frost heave, which happens in cold weather. In a frost heave, water gets under the pavement, which expands and blows up when the water turns to ice. But in a pavement buckle, a crack or joint running across the center line of a roadway fills with material that doesn't compress or tamp down, and thermal expansion causes forces strong enough to blow the pavement out." Brian Steele, spokesperson for the Chicago Department of Transportation, compares buckling to what happens in an earthquake. About 100,000 cars travel on Lake Shore Drive every day.
Heat damaged pavement is nothing new, and helps explain why tropical and semi-tropical cities such as Miami, Los Angeles and Honolulu have their own deteriorating pavement issues (i.e., potholes) to deal with. The cause is moisture under the pavement heating up and expanding, not unlike with a pressure cooker blowing its lid. Moisture in freeze-thaw conditions – factors more familiar in the upper Midwest, typically in late winter and early spring – break pavement and create potholes as moisture expands and contracts inside and under pavement cracks.

Heat Wave 2011 Explodes and Buckles Pavement

That pothole your car hit sometime in the past week: can you blame it on salt used this past winter?
If you live in Los Angeles, where potholes-per-mile are among the highest in the nation, the answer clearly is no. Los Angeles does not use salt. Never has, and probably never will. When the roads ice up in Los Angeles County, it is so rare an event that the city has no road salting supplies or methods. Almost always, it melts in a day or two with nary a granule of salt applied. The ubiquitous potholes there form because of water, wear, high temperatures and time. 
 
If you live in the Snow Belt areas that stretch from Texas and parts of the South (even Atlanta had snowy conditions in 2011) up through Denver and across the Upper Midwest and the Northeast, the salt may or may not be at fault for potholes and other forms of rough pavement. Here is why:
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<li>Salt does not affect asphalt pavement until it is already in advanced deterioration. A pothole forms when water gets under the cracks in pavement and undermines the gravel base. In situations where there is significant water accumulation infused with road salt, it might exaggerate the freeze-thaw cycle at lower air temperatures because the salt keeps the water in liquid form below 32 degrees, down to about 15 degrees. With vacillations between, say, 17 degrees and 14 degrees, there are freeze-thaw cycles that would not happen without the salt. But for the most part, salt is not the main culprit in creating asphalt potholes.</li>
</ul>
<ul>
<li>Salt can affect concrete pavement that is reinforced by steel framing (rebars). There is the matter of depacification and pH reduction, as detailed in a report from the Adirondack Watershed Institute (AWI) at Paul Smith's College in upstate New York. The report, "Review of Effects and Costs of Road Deicing with Recommendations for Winter Road Management in the Adirondack Park," explains this phenomenon as it affects concrete pavement: "Depacification refers to the break down of the passive layer of ferrous oxide that forms on the surface of steel rebar under alkaline environments. The highly mobile chloride ion [from salt] reaches the steel by leaching through the concrete and replacing some of the oxides in the passive film; without this passive layer, corrosion can occur if moisture and oxygen are available. The pH of the pore solution is reduced when chloride ions react to form hydrochloric acid. The reduction of pH accelerates the corrosion of steel, for example the corrosion rate of steel is five times faster at pH 11.5 than it would be at pH 12.0 (Jones and Jeffery, Environmental Impact of Road De-icing. In D'Itri, F.H. (Eds) Chemical Deicers and the Environment. 1991).</li>
</ul>
<ul>
<li>Salt especially affects bridge deck pavement and concrete parking garages. Because bridge pavement is famously colder and subject to freezing before roads on land, salt use tends to be higher (as is the runoff, which contributes to salt accumulations on underpasses). Bridges can be paved with asphalt or concrete, but all surfaces have steel reinforcement underneath. The AWI report cites work by the Transportation Research B (TRB, 1991) that says in snow belt states, road salt is the "single most important factor in deck repair and maintenance cost, that "15 percent of all bridges are structurally deficient due to corrosion (Koch, 1991)," and that pothole formation, vehicle damage, unsafe driving conditions, and rusting rebar that affects bearings and joints, steel framing and supports all create serious hazards. Road salt aggravates each of these problems by increasing the number of freeze-thaw cycles. It should be noted that the Federal Highway Administration has mandated protection of rebars with an epoxy coating, waterproof membranes and deck overlays and additional concrete in all construction since 1984.</li>
</ul>
</div>
Still, salt is commonly thought to be the culprit. For example, a news story out of the University in West Virginia in 2010 claimed a state department of highways engineer said, "an excessively bad winter, fierce snow conditions and heavy use of salt on the roads have contributed to a large amount of potholes." Winter conditions in general do typically lead to asphalt pavement potholes, as we now know. Unless they're talking about steel-reinforced bridge decks, the salt is not to be blamed. But the widespread belief that it does persists.
Salt has its own detractors from the environmental community. Numerous studies show that saltwater runoff is damaging to natural ecosystems, both flora and fauna. Research conducted at the University of Minnesota in 2009 found that 70 percent of the 350,000 tons of sodium chloride distributed in the Minneapolis-St. Paul region is retained in 39 lakes, three major rivers ten tributaries and several observation wells in the region. Increased salinity also affects the area's drinking water, raising salinity significantly since salting of roads began in 1950. An experiment to reduce salt use methodology by road crews on the University campus since 2007 has already cut that use by 41 percent, suggesting this can be done on a broader scale to greater effect elsewhere.
Road salt certain takes its toll on bridges, other concrete pavement and the environment. But the cause of potholes is largely moisture, hot or cold or frozen, entering cracks in pavement and undermining the roadbed. The aging road system in this country is seeing higher traffic loads than ever before while state and municipal budgets are having a hard time keeping up the maintenance of those roads.
Potholes are inevitable, whether or not you hold the salt.

Winter & Weather

In Like a Lion: March Snow Cover “Blanket” and Fresh Snowfalls Means Potholes Through Spring

How has the “Polar Vortex” affected your roads?

Hurricane Sandy's Effects on Atlantic Seaboard Roads, Pavement Widespread

Early Summer Heat Wave Buckling Pavement

Can Warm Winter Snowplow Savings Fix Potholes?

WINTER 2011 – EXTRAORDINARY POTHOLES

Can Warm Winter Snowplow Savings Fix Potholes?

Milder Winter, Fewer Potholes?

Winter 2011-2012 in the Central U.S. – and the Potholes to Come

October Snowstorm an Early Warning – About Potholes

Heat Wave 2011 Explodes and Buckles Pavement

How Road Salt Leads to Rough Pavement (Sometimes)