Illinois DOT: Using Mowing to Protect Landscapes

The Illinois Department of Transportation recounted in a recent blog post how it changed its mowing practices over the years to better protect roadside landscapes that are vital to pollinators and native planet life.

[Above photo by the Illinois DOT]

The agency has adopted mowing policies to protect the habitat and migratory patterns of the monarch butterfly and other pollinators that use it as a food source. That policy allows for mowing of the state’s roads in a four-year rotation during the summer. Interstate medians are mowed one year, westbound and southbound interstate right-of-ways are mowed the second year, eastbound and northbound interstate right-of-ways are mowed the third year, and non-interstate routes like Illinois 54 are mowed the fourth year. Then the cycle starts over.

However, Andy Stahr, Jay Keigher, and Kip Rutledge – who work for Illinois DOT’s District 3 – enhanced that program by further limiting roadside mowing along Illinois 54, which runs along a railroad right-of-way in Ford County. That encouraged the spread of native prairie plants onto Illinois DOT’s roadsides.

“We didn’t sow native seeds here,” explained Keigher, a maintenance field engineer for yards at Illinois DOT. “These plants spread from the existing remnant prairie on the railroad property. This wouldn’t be here if it wasn’t for our new mowing policy. We would’ve mowed 30 feet wide through here and we used to do that. Since we stopped doing that, I’ve seen more and more plants like these moving up our slopes and onto our backslopes.”

However – great as it is to have the railroad’s prairie spread onto Illinois DOT’s land, noted Stahr, a roadside management specialist for the agency – that doesn’t mean the job is done. While it means keeping roadside mowing to a minimum, it still means doing work to maintain what’s now considered a developing prairie.

“It’s going to be a constant problem because you have weeds coming in every direction,” Stahr added. “You’re always going to have spots where Canada thistle pops up. That’s why you can’t completely step away from it. Every once in a while you’re going to see a patch of something and you’re going to have to go in and herbicide it out and you got to reseed that little patch.”

Keigher emphasized that a lack of maintenance threatens this effort. For example, invasive Russian olive trees will block the sun and kill existing plants if left unchecked. That tree also can attract birds that transport invasive seeds through their excrement and re-contaminate the prairie with non-native and invasive plants.

Thus such invasive plants and trees must be mowed down to the ground and destroyed. “You can’t just quit,” Keigher said. “You have to keep maintaining that.”

The goal is to re-develop a prairie ecosystem that is self-sustaining – a three to five year process, Stahr noted.

“Reconstruction means applying herbicide to kill all existing vegetation at the site and scarifying the soil. Then it is managing the land for up to two years by mowing,” he explained.

“Seed also are drilled into the ground to establish a deep root system. Once it’s seeded, we really don’t have to do anything else to make it grow other than keep the vegetation and weeds down for that first year,” Stahr pointed out. “You may be able to let it go the second year if you get a great response. It’s usually the third year that you can let it go and you’ll see everything start to bloom.”

Done right, the prairie polices itself against invasive plants, he said.

“There’s only so much space in the root system,” Stahr noted. “Once you get all these plants living together in such density like this, they interlock their root systems so aggressively that when a weed seed lands in here, there’s nowhere to germinate and grow. That’s why they’re so low maintenance when you get them established.”

While Keigher would love to see every roadside receive this treatment, he prefers to do smaller quarter-mile prairie sections at a time.

“We’re expanding at the rate where we can maintain it,” he pointed out. “We just can’t do it all because we don’t have enough time to take care of it. It’s a lot. We wanted to make sure we’re successful at it before we bite more than we can chew.”

Arizona DOT Highlights Elk Fencing Project

The Arizona Department of Transportation recently highlighted the benefits of its collaboration with the Arizona Game & Fish Department (AZGFD) to reduce elk-vehicle crashes on northbound I-17 south of Flagstaff in a blog post.

[Above photo by Arizona DOT]

In 2011, AZGFD noted a high number of elk-vehicle crashes occurred along a stretch of I-17 near Munds Park.  Because a full-grown bull elk can weigh upwards of 700 pounds, crashing into something that large can destroy a vehicle and cause serious injury or death to vehicle occupants, as well as the animal. 

In 2012, after a series of studies, AZGFD and the Arizona DOT installed ungulate – “ungulate” means “hoofed mammal” – fencing in four locations near Munds Park on I-17. In most instances, Arizona DOT works crews modified existing right-of-way fences with bolts and barbed wire, eliminating the need for completely new fencing and poles.

This project produced almost immediate results, both agencies said. From the 20 documented elk-vehicle crashes that occurred along this strip of I-17 from 2007 to 2010, only one occurred between 2010 and 2014.

Arizona DOT said this is but one example of the state mitigating wildlife issues through partnerships among multiple agencies. The agency noted it also collaborated with AZGFD to construct wildlife underpasses and elk crossings along State Route 260 east of Payson and desert bighorn sheep overpasses near historic Hoover Dam on US 93.

The wildlife protection efforts undertaken by Arizona DOT are reflective of similar initiatives spearheaded by state departments of transportation nationwide.

For example, in July and August every year, the North Carolina Department of Transportation temporarily lowers speed limits from 55 mph to 20 mph on the William B. Umstead Bridge – locally known as the old Manns Harbor Bridge – at dusk and dawn during the roosting period of purple martin bird flocks.

NCDOT noted in a statement that it has collaborated with the Coastal Carolina Purple Martin Society since 2007 to educate the public about the purple martin flocks, to protect both the birds and motorists.

Meanwhile, the Colorado Department of Transportation recently completed the state’s newest wildlife overpass and underpass on U.S. Highway 160 in the southwestern part of the state, celebrating the accomplishment with a ribbon-cutting event.

To date, Colorado DOT said it has built more than 60 wildlife mitigation structures crossing above or under highways throughout the state. Additionally, it has installed 400 miles of high big game fencing along state and U.S. highways or next to the interstates.

On the research front, a report released by an international pool funded study led by the Nevada Department of Transportation in July provides an “authoritative review” of the most effective measures to reduce animal-vehicle collisions, improve motorist safety, and build safer wildlife crossings.

With as many as two million collisions with large mammals in the United States leading to approximately 200 human deaths every year, the review compiled, evaluated, and synthesized studies, scientific reports, journal articles, technical papers, and other publications from within the United States and beyond to determine effectiveness of 30 different mitigation measures.

Ultimately, the report provides best management practices to reduce animal-vehicle collisions, increase habitat connectivity, and implement cost-effective solutions, Nevada DOT said.

Environmental News Highlights – November 16, 2022


The ‘Moonshot’ Project: Creating a New Transportation Vision – AASHTO Journal

Biden takes aim at methane emissions with new rules on oil and gas industry – NBC News

Voters weigh in on transportation issues – Land Line

Can a 10-year federal infrastructure plan really sustain itself for 10 years?WFED Radio

Biden-⁠Harris Administration Announces Roadmap for Nature-Based Solutions to Fight Climate Change, Strengthen Communities, and Support Local Economies – White House (Factsheet)

US Announcements Under the Green Shipping Challenge at COP27 – US Department of State (Factsheet)

EPA Takes Action to Address Illegal Destruction of Streams and Wetlands in Missouri and Nebraska – EPA Region 7 (media release)


COVID-19 Reshaped the Work and Mobility Landscape in U.S. Cities – Government Technology


‘There are places where, if you were starting from scratch, cars wouldn’t make sense’: Pete Buttigieg on redesigning cities – Fast Company

City of Tampa testing solar sidewalk to power traffic intersection – WTVT-TV

Study Finds On-Street Lampost EV Chargers Are Lowest-Carbon Solution – InsideEVs

The Move To Re-Route Interstate 80 Has Hit A Roadblock Because Of The $12.6 Billion Price Tag – Cowboy State Daily

Taking action since Hurricane Sandy: Preparing a climate-ready workforce before the next storm hits – Brookings

California voters reject Proposition 30, the ‘millionaires’ tax for electric vehicles – Sacramento Bee

America’s First All-Electric Transit Agency Isn’t What You Might Expect – CityLab


U.S. will consider new locomotive pollution regulations – Reuters

After spending millions, TARC’s downtown Louisville electric bus fleet sits idle – WDRB-TV

Ports of LA, Long Beach, Singapore collaborate on green shipping corridor – Spectrum News 1

Vanderbilt greenhouse gas emissions drop 19 percent in two years, new sustainability report shows – Vanderbilt University


Louisiana DOTD’s Wilson: ‘Remain Committed to Equity’ – AASHTO Journal

Charlotte plans an EV sharing service at affordable housing sites – WFAE Radio


In bill gutting wetland protection, lawmakers agreed to a study. It found new law harmful – Indianapolis Star

The benefits of wetlands in Florida – WINK-TV

How beavers could help protect water quality from climate change – Colorado Public Radio

Prairies to preservation: Emerging landscape used to its advantage in maintaining roadsides in Ford County, Illinois – Illinois DOT (blog)


Utah DOT Releases All Comments On Little Cottonwood Canyon Gondola: There Are Over 13,000  – KSL-TV


Fairfax County, Virginia leaders celebrate new bicycle, pedestrian bridge over I-495 – WJLA-TV

Hawaii DOT Gets Fast and Furious Installing Raised Crosswalks – FHWA Innovator

Flagstaff adopts Active Transportation Master Plan for improved walking and biking – Arizona Daily Sun

From Rails to Trails: The Making of America’s Active Transportation Network – (book review)


State DOTs Perspective on Pavement Resilience – TRB (Webinar)

Transportation for Veterans Can Use a Blueprint from TRB – TRB

Accessibility Measures in Practice – NCHRP

Accessibility Measures in Practice: A Guide for Transportation Agencies – NCHRP

Language MattersDiversity, Equity and Inclusion Lunch & Learn – National Aging and Disability Transportation Center (Webinar)


Delegation of New Source Performance Standards and National Emission Standards for Hazardous Air Pollutants for the States of Arizona and California – EPA (Final rule)

Pipeline Safety: Notice of Availability of the Tier 1 Nationwide Environmental Assessment for the Natural Gas Distribution Infrastructure Safety and Modernization Grant Program – Pipeline and Hazardous Materials Safety Administration (Notice)

Tongass National Forest; Alaska; Mendenhall Glacier Visitor Facility Improvements Project – Forest Service (Notice of intent to prepare a supplemental draft environmental impact statement)

Notice of Intent To Amend the Las Vegas Resource Management Plan and Prepare an Environmental Impact Statement for the Proposed Copper Rays Solar Project in Nye County, Nevada – Bureau of Land Management (Notice)