MnDOT Trying to Cut Back on Its Salt

When it snows in Minnesota, drivers want the roads and bridges cleared – now.

However, simply dumping mass amounts of salt on the roads is an outdated practice for the Minnesota Department of Transportation. Today, the agency is taking a new strategic – and more environmentally friendly – approach to how it removes snow and ice.

[Above photo by the Minnesota DOT]

“We want to minimize what we use,” explained Sue Lodahl, Minnesota DOT’s acting state maintenance engineer. “It’s about using the right chemical at the right time in the right location.”

During the 2020-2021 winter season, the agency spent $116 million and used more than 800 plow trucks and 354 million pounds of salt to combat 53 inches of snowfall, according to the department’s Annual Winter Maintenance Report. The salt usage was down about 15 percent from the previous year.

[To learn more about snow and ice fighting tactics, check out the winter operations podcast put together by the American Association of State Highway and Transportation Officials Snow and Ice Pooled Fund Cooperative Program, known as “SICOP.”]

The Minnesota DOT has also published “Winter Maintenance Best Practices,” a guide for using salt, with an emphasis on sustainable practices. “MnDOT seeks to reduce the use of salt on roadways while maintaining a high level of performance with regard to level of service recovery in winter operations,” the guide states.

The department’s Salt Solutions Program helps operations personnel make good decisions about selecting the best and safest materials for clearing the roads. As a result, the Minnesota DOT’s maintenance crews now have an arsenal of tools to fight snow and ice – including salt, potassium acetate, calcium chloride, sodium acetate and even beet juice.

[Editor’s note: The Minnesota DOT also began testing the technology on 10 of its snowplows in January that allows operators to activate digital highway signs to warn motorists when slow-moving vehicles are ahead on the road. That technology activates digital message signs to display certain messages as they pass, such as “Snowplow ahead, use caution” or “Maintenance vehicle ahead, use caution” during non-snow events. The message stays activated for several minutes after the snowplow passes the sign.]

[Above photo by the Minnesota DOT]

Even with all the chemical options available, plain road salt – sodium chloride – is still the “go-to” material, yet it has its limitations. Salt is not effective if the temperature drops below 15 degrees Fahrenheit.

Moreover, if salt washes off the road, it can harm water, vegetation, and wildlife.

“We’re always going to use granular salt, but we’re trying to keep it on the road,” Lodahl said. “You can’t just put down salt. Otherwise, it will go into the environment.”

The Minnesota DOT also “pre-wets” the salt with truck sprayers just as it hits the road. The water helps the salt stay on the roadway, where it reacts to the heat from vehicle tires. “But if the temperature is less than 15 degrees, that’s when we move into calcium chloride,” Lodahl pointed out.

The department’s top priority is to achieve what it calls “bare lanes,” a condition in which 95 percent of the lane between the wheel tracks is free of snow and ice and travel speeds are not impacted. Last winter, the Minnesota DOT saw bare lanes 87 percent of the time. The Salt Solutions Program’s goal is to strike a balance between achieving bare lanes and protecting the environment.

In 2020, the agency also studied using potassium acetate almost exclusively on roads in Duluth, where the average daily winter temperature is 23 degrees. The study showed promise, but there are still some environmental unknowns about the long-time use of potassium acetate, Lodahl said.

“Salt is still our biggest tool, our best tool,” she explained. “Everything is going to have some environmental factor. If salt scatters, it’s not doing us any good, and it harms the environment.”

Lodahl added that salt sustainability “is very important to MnDOT. We cherish the environment and try to keep the roads safe.”

AASHTO’s ETAP Podcast: Monarch Butterfly Conservation with Kris Gade

Once ubiquitous in North America, the Monarch’s striking orange and black wings are likely the first image that comes to mind when picturing a butterfly. The Monarch is famed not only for its beauty but also for its role in a healthy ecosystem- the pollinators are a critical support to some uniquely American landmarks: from the Great Smoky Mountains to Zion National Park. Yet, over the past few decades, the Monarch has experienced a dramatic dip in population.

As the eastern members of this iconic species prepare for their annual migration to Mexico, we’ll sit down with Arizona Department of Transportation’s Roadside Resource Specialist, Kris Gade– one of the professionals leading the charge for Monarch conservation.

Tennessee Agencies Work Together to Support Pollinator Species

The Tennessee Department of Transportation, along with the Tennessee Department of Environment & Conservation (TDEC) and Tennessee Department of Agriculture (TDA), jointly promoted “pollinator health and awareness” in state parks during National Pollinator Week June 21-25.

[Above photo of Monarch Butterfly via Wikimedia Commons]

The three agencies formed a partnership in 2019 to support 64 acres of “pollinator meadows” at eight state parks. Each blooming meadow contains a mix of nectar-bearing plants and milkweed, which sustain pollinators such as bees, moths, butterflies, birds, and small mammals such as bats.

The meadows also assist with TDEC’s Honey Project, which allows the public to purchase honey harvested annually within each park.

“We are excited about this partnership,” explained Clay Bright, Tennessee DOT’s commissioner, in a statement. “This effort is an excellent way to educate the public about the threats to pollinators and a valuable part of our Pollinator Habitat Programming.” 

On a national basis, the American Association of State Highway and Transportation Officials sent a two-page letter to the U.S. Department of the Interior in March 2020 supporting “expedited approval” of the voluntary national Candidate Conservation Agreement with Assurances or CCAA to further encourage the creation of pollinator habitats in highway rights-of-way.

In December 2020, the Transportation Research Board highlighted a bevy of resources available to state departments of transportation to support monarch butterfly habitat and migration support efforts.

To that end, a new report from the TRB’s National Cooperative Highway Research Program – Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies – provides guidance for roadside managers to determine the potential of their roadway corridors as habitat for monarch butterflies. The report also includes several tools and decision-support mechanisms to optimize habitat potential in a manner that is compatible with the continued operation and maintenance of the roadside.

Illinois DOT Mowing Program also Protects Pollinator Habitat

The Illinois Department of Transportation recently resumed statewide roadside mowing operations, now scheduled to help maintain and grow pollinator habitat.

[Above photo by the Illinois DOT]

“We are committed to protecting the environment in the work we do every day,” noted Omer Osman, Illinois DOT’s recently confirmed secretary, in a statement.

“By combining well-defined vegetation management with mowing cycles that preserve sightlines and maximize safety, we can make a positive impact today and for future generations, [as] pollinators play a key role in the state’s ecosystem by aiding in reproduction of flowers, fruits and vegetables,” he said.

Throughout the summer, the agency noted that it conducts two primary types of mowing: Safety mowing, which occurs directly adjacent to the road as needed, and maintenance mowing, which includes areas next to culverts, ditches, traffic control devices and other structures.

The Illinois DOT noted that in recent years it revised its mowing practices to help create and maintain habitat for pollinators – including the endangered rusty patched bumblebee and the monarch butterfly – cataloged in its Illinois Monarch Project Mowing Guidelines for Pollinators.

By mowing at select times and reducing the amount of land mowed, IDOT encourages the growth of plant species such as milkweed, the only food source for monarch caterpillars.

In 2020, the Illinois DOT said it joined in the launch of the Illinois Monarch Action Plan as part of the Illinois Monarch Project, a collaborative effort to help ensure the survival and successful migration of monarchs by increasing and protecting habitat.

Alongside that effort, in March 2020, the American Association of State Highway and Transportation Officials sent a two-page letter to the U.S. Department of the Interior on March 12 supporting “expedited approval” of the voluntary national Candidate Conservation Agreement with Assurances or CCAA to further encourage the creation of pollinator habitats in highway rights-of-way. “The regulatory protections provided by this CCAA allow transportation agencies to continue vegetation management practices with less concern that these actions will lead to an increase in the costs of regulatory compliance if the monarch is listed under the Endangered Species Act,” the organization said in its letter. “We see the CCAA as advancing … guidance developed by the Federal Highway Administration on practices to support pollinator habitat.”

When Guano Happens, State DOTs Call on the Falcon

Several state departments of transportation are helping bring back the Peregrine falcon from the brink of extinction by providing nesting platforms on bridges – creating a true symbiotic relationship that protects bird and bridge.

[Photo by Michigan DOT.]

By the 1970s, Peregrine falcon populations were nearly wiped out in the United States, partly because of the widespread use of the pesticide dichloro-diphenyl-trichloroethane – more commonly known as DDT – made the falcons’ eggshells too brittle. The ban of DDT helped to re-establish the falcons, which prefer to lay their eggs on ledges at high altitudes.

Meanwhile, state DOTs across the U.S. were battling the corrosive effects of pigeon guano, which can eat away at the concrete and steel on bridges as well as pose cleanup hazards for work crews.

Enter the falcon, which loves to feast on pigeons – or at the very least scare them away.

The Michigan Department of Transportation is one of several DOTs that encourage falcons to nest under their bridges. In 2010, the Michigan DOT placed a simple wooden platform on the Sault Ste. Marie International Bridge across the St. Mary’s River to provide the birds a safe nesting place, according to Dan Weingarten with Michigan DOT’s Office of Communications. So far, the platform has been home for 30 falcon chicks that have hatched, helping locally re-establish the species.

[Editor’s note: You can view a live camera feed of the falcons by clicking here.]

The platform is a win-win for MDOT, which does not want the pigeons and their acidic droppings, and the falcons, who need a high-altitude home for nesting and hunting.

“One of the reasons it seemed like a good fit is they would prey on or scare away the pigeons,” Weingarten said. “It seems to have worked. The pigeons at least moved.”

Photo by Michigan DOT

In 2013, the Michigan DOT installed two more platforms at the Portage Lake Lift Bridge that have produced 24 chicks. Crews have since relocated those boxes to other locations because of bridge repair work, but many other states have active falcon nesting programs on their bridges.

One of the first states to get into the falcon platform business was Virginia, which placed a nesting box on the Coleman Bridge in the early 1990s. Since then, the Virginia Department of Transportation has placed several more platforms on other bridges – work that greatly benefits the falcon population, according to a report from The Center for Conservation Biology.

“Bridges have made a significant contribution to the Virginia peregrine falcon population,” supporting more than 30 percent of the known falcon population in the state, the report noted.

Other states – including Connecticut, Massachusetts, New Jersey, New York, and Ohio – also have built and installed platforms to welcome the peregrine falcon to nest in their bridges. “Infrastructure is a small part of the comeback story of these birds,” Michigan DOT’s Weingarten said. “But it’s definitely played a role in re-establishing them.”

Tennessee DOT Helps Fund Two Trash Exhibits at Aquarium

A pair of new exhibits at the Tennessee Aquarium funded by the grants from the Tennessee Department of Transportation illustrate how microplastics and other roadside trash can negatively affect the health of the ocean as well as rivers, lakes, and streams.

[Above photo by the Tennessee Aquarium]

The new exhibits – housed in the Aquarium’s “River Journey” and supporting the Tennessee DOT’s “Nobody Trashes Tennessee” litter reduction campaign – includes actual debris taken from the banks of the Tennessee River

The exhibits demonstrate the connection between land-based pollution and aquatic ecosystems through “touchless” interactive elements, informative videos, and an exhibition of invasive aquatic wildlife such as a Northern Snakehead and Grass Carp. Those non-native fish are housed in one of the exhibits, swimming alongside examples — some of them 3D-printed — of common roadside debris such as tires and car batteries, which can wreak havoc on aquatic systems.

“The connections between roadside litter, water quality and aquatic systems cannot be understated,” said Shawn Bible, Tennessee DOT’s beautification office manager, in a statement.

“The ‘Nobody Trashes Tennessee’ campaign aims to educate citizens on the impact of what may be perceived as a minor issue for the state,” Bible added. “In reality, the state spends more than $19 million each year to clean up the more than 100 million pieces of litter on our roadways. We are pleased to partner with the Tennessee Aquarium on these interactive exhibits.”

The exhibits help visitors visualize how trash can imperil aquatic ecosystems and impact waterways that millions rely on for recreation and drinking water, while also demonstrating how changes in behavior on land can benefit the health of nearby waterways, explained Dr. Anna George, the Aquarium’s vice president of conservation science and education.

“Anything that is on land moves into our waterways,” Dr. George said. “If a piece of litter is thrown onto a street, wind might carry it to a stream or river. It might get washed or blown into storm drains and deposited in the nearest body of water. It is a safe assumption that any debris on land has a good chance of winding up in our water.”

According to the National Oceanic and Atmospheric Administration, 80 percent of garbage found in the ocean comes from inland sources, such as leaked automotive fluids and littering. “So even though the [Tennessee] Department of Transportation might seem like an odd partner for an aquarium, there’s a fundamental connection between activity on land and the health of waterways,” Dr. George noted.

ITD Shares Award for Eco-Friendly Bridge Work

The construction of the new Rock Creek Bridge to replace a culvert on US-20 recently won an engineering excellence award from the American Civil Engineers Council of Idaho – an award shared by the Idaho Transportation Department (ITD) and Jacobs Engineering.

[Photo by the Idaho Transportation Department.]

The new bridge now allows wildlife to pass under the highway, reducing the risk of possible collisions involving wildlife and vehicles on the roadway. The ITD added in a statement that this particular section of US-20 witnessed 64 vehicle-wildlife collisions over the last five years, which totals a “societal cost” of approximately $2 million when adding together the cost of vehicle repair or replacement, medical bills, and increased insurance rates – not to mention the cost to wildlife.

The project also allowed the ITD to restore the streams forded by the new bridge to a more natural condition, which in turn should positively benefit the surrounding ecosystem by encouraging safer fish passage under the highway.

Building a bridge also reduced the impact on the local environment versus replacing the existing multi-plate culvert with a similar culvert design, ITD added.

This was one of ITD’s first projects incorporating ‘fabric encapsulated soil lifts’ into a design – a way to ensure streambank stability as water levels rise and fall while still promoting vegetative growth. The project has already improved the environment while enhancing the safety and the natural beauty of the project area, ITD added. Just a few months after construction, the agency spotted fish swimming upstream to spawn, while noting several deer – and a moose – traveled along the channels under the bridges.

TRB Provides Support Resources for Butterfly Conservation Efforts

The Transportation Research Board recently highlighted a bevy of resources available to state departments of transportation to support monarch butterfly habit and migration support efforts.

[Photo courtesy of the Virginia Department of Transportation.]

A new report from the TRB’s National Cooperative Highway Research Program – Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies – provides guidance for roadside managers to determine the potential of their roadway corridors as habitat for monarch butterflies.

The report also includes several tools and decision-support mechanisms to optimize habitat potential in a manner that is compatible with the continued operation and maintenance of the roadside.

TRB noted in a blog post that a 2014 Presidential Memorandum “influenced” its recent research on monarch butterfly conservation – a memorandum that encouraged the Federal Highway Administration to work with state DOTs, transportation associations, and roadside managers as part of a holistic approach to promote the health of pollinators.

TRB added that forthcoming research from NCHRP will help craft a “guidebook” to help decision-makers tailor programs to maximize insect pollinator habitats along roadways. That guidebook will consider additional public benefits, roadway characteristics, and safety, as well as the geographical, adjacent land use, and ecological contexts. Butterflies and other pollinators are only a small subset of the wildlife benefiting from informed transportation planning.

In April, the U.S. Fish and Wildlife Service and the University of Illinois-Chicago signed what they called a “historic agreement” to encourage transportation and energy firms to voluntarily participate in monarch butterfly conservation by providing and maintaining habitat on potentially millions of acres of rights-of-way corridors on both public and private lands.

Both signed an integrated, nationwide candidate conservation agreement (CCA) and candidate conservation agreement (CCAA) for the monarch butterfly on energy and transportation lands throughout the lower 48 states.

The USFW noted that those formal yet voluntary agreements between the agency and both public and private landowners aim to conserve habitats that benefit at-risk species. It also “integrated” both CCA and CCAA programs so energy and transportation partners and private landowners can provide conservation seamlessly throughout their properties where there may be a mix of non-federal and federal lands.

Video: WSDOT Makes Bridge Safer for Human Travelers & Fish Species

The Washington State Department of Transportation recently wrapped up a roughly $13 million fish barrier correction project – resulting in a new 440-foot bridge that spans Kilisut Harbor along State Route 116. The new bridge not only improves safety for human travelers but also is, in the words WSDOT Project Engineer Dan McKernan, a “huge win” for local salmon and other fish species in the area.

[Photo courtesy of Washington State Department of Transportation.]

“The work involved replacing two small culverts that were installed in the 1950s. The channel here now with the bridge was not here previously,” he said, adding that the new channel aids in the annual migration of salmon in the area.

This work is part of WSDOT’s Fish Barrier Removal Program, which identifies and removes barriers to fish caused by culverts under state highways. The agency noted in a statement that it worked with the North Olympic Salmon Coalition or NOSC to complete this specific bridge project while also continuing to work with the Washington State Department of Fish and Wildlife to identify locations where culvert replacement will increase fish habitat.

“The area between Indian and Marrowstone Islands was historically comprised of tidal channels and salt marsh,” NOSC noted in separate statement. “Tidal waters exchanged freely between Oak Bay and Kilisut Harbor, flushing cold water, moving sediment, and allowing juvenile salmon to migrate northward from Oak Bay into the shallow, productive waters of Kilisut Harbor. The installation of the causeway in between Kilisut Harbor and Oak Bay eased transportation between the Islands, but choked the flow of water and sediment, eventually creating an artificial beach berm, a filled channel, and increased water temperatures in Kilisut Harbor.”

The construction of the new bridge also resulted in the removal that land barrier, reconnecting the large numbers of Hood Canal and Puget Sound out-migrating juvenile salmon that converge at Oak Bay with immense foraging opportunities available within Kilisut Harbor while also restoring and enhance important staging and foraging habitat for multiple coastal dependent and migratory birds. “Clean, cold water is now flowing north into Kilisut Harbor/Scow Bay,” the organization noted. “This mixing on each tide cycle is expected to improve water quality in Kilisut Harbor over time.”

NYSDOT Helps Expand Artificial Reef off Long Island

The New York State Department of Transportation is helping expand a series of artificial reefs off the shores of Long Island as part of a three-year long multiagency effort. In September, the agency helped dump a retired tugboat, 16 rail cars, and a streel turbine on Hempstead Reef – the first of multiple “reef deployments” scheduled for 2020.

[Photo courtesy of New York State DOT.]

NY Governor Andrew Cuomo

In his 2020 State of the State address, Governor Andrew Cuomo (D) committed to doubling New York’s existing reef acreage by expanding seven of 12 existing sites and creating four new artificial reefs in Long Island Sound and the Atlantic Ocean – an expansion expected to be complete by 2022.

“[We are] proud to work with our sister agencies on this important program, repurposing transportation materials to expand artificial reefs and support biodiversity, fishing, and tourism,” explained Marie Therese Dominguez, NYSDOT’s commissioner, in a statement.

“It is another example of how [our state] is taking bold steps to protect our ecosystems and foster sustainable economic growth that will benefit current and future generations of New Yorkers,” she said.

The New York State Department of Environmental Conservation or DEC manages the state’s 12 artificial reefs, which include two reefs in Long Island Sound, two in the Great South Bay, and eight in the Atlantic Ocean. The 413-acre Atlantic Beach Reef is located three nautical miles south of Atlantic Beach with a depth of 55 to 64 feet. One of the first reefs created in New York, this reef was previously comprised of two vessels, nine barges, surplus armored vehicles, 404 auto bodies, 10 Good Humor trucks, steel crane and boom, rock, concrete slabs, pipes, culvert, decking, and rubble.

Moving forward, recycled materials from NYSDOT, New York Power Authority/Canal Corporation, and the Thruway Authority – among other public and private partners – are being put to new use to develop New York’s artificial reef sites.

The types of materials deployed onto the reefs from the NYSDOT over the last year include old concrete highway barriers, steel girders with concrete tops from the Staten Island Expressway, and 15 steel pipes from the old Kosciuszko Bridge; replaced by a new structure that opened in 2019.

Photo courtesy of New York State DOT

The DEC said those materials are then “strategically placed” to expand the reef, with the agency overseeing the cleaning of contaminants from recycled reef materials to mitigate potential impacts to sea life before being deployed to the reef sites. Once materials and vessels settle to the seafloor, larger fish – such as blackfish, black sea bass, cod, and summer flounder – move in to inhabit the new structures, and encrusting organisms such as barnacles, sponges, anemones, corals, and mussels cling to and cover the material. Over time, the recycled structures create a habitat mimicking that of a natural reef, DEC noted.