The Transportation Research Board's Performance Measurement Committee's newest newsletter was published today, containing an article by Salt Institute president Dick Hanneman on the role of roadway friction measures to rate the effectiveness of winter maintenance efforts . "Friction measuring devices create accountability for outcomes for the first time," explained Hanneman. Hanneman serves as liaison between the TRB Performance Measurement Committee and TRB's Winter Maintenance Commitee.

Highway maintenance operators are continually barraged with advertising claims on the benefits of various deicing compounds. The number of conflicting claims out in the marketplace make it difficult to arrive at a decision one can comfortably live with. One of the areas of greatest contention is the effect of various deicing chemicals on pavement concrete.

I recently took part in an excellent Snow and Ice Meeting at Villanova University organized by Greg Nichols of Bryn Mawr College. During the course of that meeting, one of the speakers, who represented a deicing technology company in Iowa, told the participants of the highly deleterious effects of sodium chloride on concrete. Of course, it was the job of this individual to sell his particular brand of product. But was what he said about the deleterious effects of sodium chloride on concrete correct?

Among its various roles, the Salt Institute carries a strong educational component. In serving that role, we have to make use of the most reliable, objective sources of information available. With reference to the latest research on the impact of various deicing chemicals on pavement concrete we turned to Iowa State University's Department of Geological and Atmospheric Sciences.

In a comprehensive paper authored by H. Lee, R. D. Cody, A. M. Cody, and P. G. Spry, entitled,

Effects of Various Deicing Chemicals on Pavement Concrete Deterioration

these researchers described their comprehensive investigations into the effects of different deicers on concrete deterioration. The materials they used were sodium chloride, calcium chloride, magnesium chloride, calcium magnesium acetate (CMA) with 5 different Ca/Mg ratios, Ca-acetate, and Mg-acetate. Each deicer produced characteristic effects on the concrete samples by physically and chemically altering the dolomite coarse aggregate, the dolomite coarse aggregate-paste interface, and the cement paste.

Their study conclusions revealed that magnesium in any form was the most damaging to the concrete. Magnesium chloride produced significant concrete crumbling and that calcium magnesium acetate (CMA) solutions were the most damaging of all solutions tested. Wet/dry and freeze/thaw cycling in CMA produced widespread and severe damage. Magnesium acetate produced similar damage.

Most significant of all, under the experimental conditions they employed, sodium chloride was the least deleterious material to concrete.

Blizzards have closed the Denver airport and roads for a hundred miles and paralyzed the high plains economy, but I'll be heading home soon on dry roads for an evening's TV date as my beloved Green Bay Packers host the neighboring Minnesota Vikings this evening. (It's been a long season for faithful Packers fans, but that's another story).

Just up the road from us here in Northern Virginia, fans of the Baltimore Ravens are getting excited for the prospects of their team in the NFL's post-season (just a dream for the 2006 Packers, I'm afraid). Yesterday's Baltimore Sun carried the headline: "Ravens' success has city thinking salt and purple" It seems the city's salt this year is blue (from the use of Prussian Blue as an anti-caking agent, the paper didn't mention) and they're taking a look at trying to adjust the hue to honor the purple-and-black Ravens. The city has already changed the lighting on city buildings to purple. The paper explains that "winter in Baltimore may resemble a huge, grape-flavored snowball."

Keep praying for snow in Baltimore, even if purple's not your favorite team's color. And tonight I'm hoping there's no cause to consider a "purple" celebration after the game as my green-and-gold champions tough it out with an outfit that used to inspire "shock and awe" as the "Purple People Eaters" -- the Vikings.

"DOT banishes sand from snowy highways" read the December 15 headline in the Connecticut Post Online . "Instead of seeing the brown ick of sand polluting the landscape," Connecticut drivers will soon see clear, black roads when it snows, explained journalist Rob Varnon. The CT DOT has replaced sand-salt mixes with straight salt -- the solution used in most states and the strong trend among professional snowfighters. Varnon continued:

Sand has traditionally been used to create traction on winter roads, but studies by the U.S. Department of Transportation and several universities during the last decade have called its effectiveness into question....The state DOT said it plans to use plows, salt and liquid calcium chloride to clear roads and also treat some surfaces before storms. ...Municipalities do not have to follow suit, but Connecticut requires towns and cities to clean up sand when it is placed on the roads because of the impact the material has on water supplies....The DEP discussed the DOT's winter plan, he said, and applauds the decision to quit using sand. Massachusetts, Vermont and New York have quit using sand because it is detrimental to the environment, he said.

Not only will switching to salt reduce the environmental burden, a DOT spokesperson said, but the public demands winter mobility only possible by using salt. "People are less and less patient. The DOT catches a lot of political heat if the roads aren't clear 24 hours after a storm," he explained.

Yes, we know. Good move, Connecticut!

Ten crashes in Ft. Wayne, IN have been blamed on an IN DOT anti-icing application of calcium chloride with a rust inhibitor which the agency confesses caused rather than prevented slickness. Four crashes caused injuries according to a sotry in the Ft. Wayne Journal Gazette .

Tragic, of course, but agencies are simply responding to public concerns that they find some "alternative" to using tried-and-true sodium chloride and such incidents are the inevitable result of experimentation with new materials and techniques. Let's be clear, however, anti-icing itself wasn't the problem here, nor was salt (sodium chloride) involved in any way.

In the salt business, there is seldom any question as to what a Dome is. High pressure on embedded salt deposits in the earth's crust causes the salt to flow up plastiically, often with a bulging top. The characteristic, rounded water-tower-shape formation, resulted in the name salt domes, particularly in the Golf Coast area. So it was with a bit of surprise that I read of the massive salt dome in UK's Ribble Valley, rural Lancashire's country escape. Of course, Lancashire is Northwest England's home of Liverpool and Manchester, so having access to a country retreat is a great benefit to all those working in that heavy industrial environment - but the headline read, Massive salt dome to keep roads safe. Was this a new source of deicing salt?

No, not, nyet!

The article described a marvelous new structure designed to house the salt required to keep the winter roads of Ribble Valley and the surrounding area open throughout the winter season. County councillor Tony Martin, cabinet member for sustainable development correctly characterized the benefits of winter salting by stating,

Nobody realises until it's not done one day.

The council made the investment in this huge structure to ensure an adequate supply of salt for the season. They wanted to make sure that the good people of industrial Lancashire continue to have access to that marvelous country retreat of Ribble Valley.

The word Dome originally meant house in is the English language. It came from the Latin domus, which itself was traced back to the Greek domos and Sanskrit dama. In Italian, the word duomo came to mean house of God, and since all Italian cathedrals had cupolas, the word dome attached itself to that bit on top.

One often gets the uncomfortable feeling in reading news accounts about property rights and land use that various advocacy groups' full agenda isn't on the table. Take an account in today's Washington Post , for example, entitled "Town vs. Gown in D.C."

George Washington University in Washington, DC, wants to make a quarter billion dollar investment in commercial properties it already owns in order to increase its ability to generate revenues for the school. Neighbors want to preserve a less intensive development plan. That much seems straightforward, though the neighborhood group is promoting its view in the context of GWU's adherence to its approved development plan.

Likewise, those who advocate restrictions on residential property development rights in the name of "smart growth" would have us set aside suburban visions of green lawns on generous lots with lots of blue sky and few tall buildings in favor of a more intense and vertical urban development clustered around mass transit, with sidewalk cafes and bustling nightlife. This, they say, will deliver a quality lifestyle and contribute to lowering environmental stress, particularly air pollution. The City of Portland, OR has established a pilot test of "smart growth" and its results include massive increases in property value since the city has ignored demand and constrained supply. In that regard, Robert Bruegmann's recent book, Sprawl: A Compact History, is well worth a read. But I digress.

My point is that accommodating growth in the U.S. necessitates development somewhere. Fifteen years ago, we had 250 million people living in the U.S. Today, we're over 295 million, up nearly 20% in that short time. If ours is to be a leafy surburan American Dream, okay. If it's to be a livable city (most would conjure up a European city like Paris), fine. But the anti-car, anti-highway argument of "smart growth" advocates requires urban growth as an alternative. Those who live in the central cities and those who live in the Inner Suburbs, as I do, are not immune to reflexive NIMBY myopia.

The gestation of our highway transportation network is the choices we each make on where to live, shop, work and recreate. If we don't want development, that's one thing and let's just say it. If we want to deny development in the Inner Suburbs or Central City to spike property values there, admit it. There has to be an option for development. If everyone cries NIMBY, we risk paralysis and gridlock. Let's keep in mind that congestion is the major source today of air pollution, not cars per se.

It's no secret: while most folks see a snowstorm as white -- and an inconvenience if not a threat to their driving safety -- those of us in the salt industry, like ski operators, see the same snowstorm as green -- a natural phenomenon that increases our market (for deicing salt and lift tickets). A "good winter" from a salt 'n ski perspective means lots of snow leading to musings about why we can't have more of that white stuff.

I respond that if technology made it possible to control the weather, the first result would be the natural "there oughta be a law" call to ban snowfall, at least on highways. But, of course, we can't control the weather, can we?

Not to fear, your tax dollars are at work. The Utne Reader reports a Defense Technology International story that "the US Air Force is developing technology that would actually allow it to control the weather. Military scientists have been experimenting with plasma technology that would 'reconfigure the ionosphere' for military purposes. The idea is to sneak up on enemy fighters and change the atmosphere to prevent them from receiving satellite signals."

Now, THAT's climate change!

Winter started out right in the DC area in December, but disappeared entirely in January. It's back, forecasters tell us. Appropriately, this morning's Washington Post has a story on the job of weather forecasters. As with the advance of freedom in the world and the resilence of the U.S. economy's growth despite 9/11, Katrina and oil prices, an important and underappreciated story is the significantly improved performance of road weather information systems (RWIS). These aren't the forecasters in the Post story, but rather the data systems that tell roadway maintainers the pavement temperature so they know when to put down salt. For more on road weather, check out the Salt Institute website .

Shameless plug: the Salt Institute's new Salt and Highway Deicing newsletter is now available online, discussing the important differences betweeen "winter maintenance" and "winter operations." You can subscribe for future issues of this free newsletter.

I've just received the Fall 2005 issue of Access , the newsletter of the University of California Transportation Center. This edition isn't yet online.

I was struck by a couple factoids in the article "What We've Learned About Highway Congestion." From the Cal-Berkeley PeMS database , researchers have determined that maximum highway capacity is achieved at about 60 mph, up sharply from the 40-45 mph estimated earlier. Research also shows that only 21% of congestion is due to "excess demand" -- too many vehicles for the design of the roadway; the other 79% of congestion is due to operational failings such as weather, traffic crashes or failure to provide metered ramp access to freeways. This, of course, underlines the priority that should be given to investing in highway operations -- like snow & ice control. Another tidbit: high-occupancy vehicle (HOV) restriction does encourage carpooling, but otherwise it acts perversely to increase congestion. "Analysis of Bay Area data suggests that the effeect of teh combined penalties is larger than the positive carpooling effect. Thus, the likely net result of HOV restrictions in the Bay Area is worsening congestion."

Kinda sounds like the situation we face in salt restriction, ostensibly to improve health and reduce heart attacks. Good theory, but the "net result" may be a worsening of public health (see other posts in this blog).

The Chicago Tribune reports the Windy City is off to its snowiest start in 27 years. Commute times in normally-excellent-snowfighting Chicago lengthened from one hour to five hours. Preparation and training are the keys to executing good winter operations. In Illinois, a study by Global Insight , commissioned by the Salt Institute earlier this year, found that failing to clear roadways costs $350 million every day, including $220 million in lost wages and nearly $100 million in lost retail sales. At Christmas-time, the lost sales could be even higher! The Salt Institute website has more information on winter safety and mobility .

Winter's here. No matter your politics, the Washington Post got this story right. The DC metro area was blanketed with 3-5 inches of snow and salt trucks were hard at work. Although local forecasters didn't call it just right, winter's first snow is a wake-up call that snowfighting, often the largest public works expenditure of snowbelt governments, is off to a strong start. For more information, see our website at http://www.saltinstitute.org/30.html .

Every year we're flooded with calls from areas of the U.S. where winter ice storms inflict unexpected carnage and paralysis by overwhelming unprepared public works agencies. But at least that's the exception in North America. It's one area where Asia is still catching up as this report from Seoul reminds.

"If a car slips on ice, intelligent (roadway) systems could not only inform other drivers but send a notice through the receivers alongside the highways to road crews that salt or sand is needed. Such systems could even be programmed to stop cars before an accident occurs - without driver involvement." So says GreatestJournal! in a blog post today.

That's true and there's other good news as well.

There are tremendous highway safety benefits inherent in new Intelligent Transportation Systems. Road Weather Information Systems today send road maintenance professionals data on roadway surface conditions from embedded sensors so that salt trucks can deliver their lifesaving service when snow and ice threaten safe driving conditions. More information can be found on the Salt Institute's website .