Engineering the Snow and Ice Away

For Massachusetts residents, the winter of 2015 will not be one soon forgotten. As the Boston area reached 108.6 inches of snow — officially breaking its all-time seasonal snowfall record — news reports continue to cover roof collapses, traffic accidents and more than a few stir-crazy residents desperate for a sunny day.

But perhaps city residents' biggest frustration was with Boston’s stressed transportation system. Impassible streets, stalled above-ground subway cars and long delays at the city's airport stranded travelers and brought a great American city to a grinding halt more than once. Even with Spring in sight, Boston (and plenty of other spots across the U.S.) still can't say with certainty that those snow days are over just yet.

How a modern city keeps its citizens moving during even the worst snowfalls is not just a question of easing discomfort and alleviating inconvenience. It's an economic imperative: By some estimates, the winter of 2015 has cost the Boston-area $2 billion in economic losses.

But technology is doing its best to keep those costs down and keep travelers moving — here in the U.S and abroad.

Major U.S. snow-belt cities are adopting an "Internet of Things" mentality when it comes to clearing streets — using GPS tracking technology to keep residents up-to-date on snow-plow activity. For instance, New York City residents can pull up an interactive web-based map to see where plows are currently working. In Boston and Buffalo, GPS sensors let central city computers know when a plow has moved through a street, triggering automated alert systems for citizens.

Beyond GPS, computer engineers across the globe are using artificial intelligence (AI) to solve the routing problems that can make street-level snow removal a thorny — and inefficient — process. Finding the optimal path for plows to clear all of a city's streets in the most efficient manner possible — that is, finding the shortest distances to travel, making the fewest U-turns possible while still prioritizing high-traffic areas first — is a task tailor-made for this era’s algorithmic geniuses.

In Centennial, Colo., one of the first cities in the U.S. to apply AI algorithms to its snow-plowing process, streets were cleared up to 40 percent faster.

On the chemical side of the equation, road and airport de-icers have posed a different kind of perplexing problem for municipal planners.

Sodium chloride, magnesium chloride and calcium chloride — simple salts — are great at melting ice and snow. They work by lowering the melting point of water and have been used for decades to keep roads and runways clear during snowy periods. These chlorides are easy to create and plentiful.

They're also controversial.

A recent study in Michigan found that up to 30 percent of the rock salt spread on streets during the winter quickly bounces off or is blown away.

Many municipalities have instead turned to a "brine" — a liquid solution of chlorides that's more likely to stay where its sprayed, offers better coverage and requires a smaller concentration of chlorides, which is better for the environment.

(The solution, however, is not without its detractors: Brining streets requires new equipment and is more expensive, and a growing number of critics complain that salt-based road treatments are increasing truck, car and bridge corrosion.)

At the airport, modern science has given us de-icers — the liquid concentrations of petroleum-based glycols sprayed on planes to keep ice and snow from accumulating before the plane takes off. (Technically, de-icers are used while sitting at the gate, anti-icers — which have a higher concentration of glycol to stick to the plane — are used just before takeoff). These petroleum-based de-icers face the same problem as rock salt — after they do their job, they have a tendency to end up in the ground and waterways — a cause for concern for both humans and the environment.

But that may be changing.

Instead of petroleum-based chemicals, deicers can now be produced with glycol made from renewable feedstocks. DuPont Tate & Lyle eco-friendly Susterra® propanediol, which is made through the fermentation of glucose originating from industrial corn, can be used in aircraft wing de-icers and even to clear runways. It's sustainable, uses less energy to produce and is effective at very cold temperatures!

Keeping a major city or a major airport humming during the worst that nature has to offer is one of the miracles of modern life. It's a dance of coordination, chemistry, and foresight, made possible by incredible engineering achievements that help us fight nature’s fury even as we strive to protect her.