Of Bats, Bridges, and Culverts: Part 1

There may be a new mammal vying for the title of man’s best friend – and a new study is looking into how Texas Department of Transportation bridges may be key to this profitable mammal-human connection.  

Dr. Stirling Robertson, the biology team lead within Texas DOT’s natural resources management section, explained that bats help preserve the health of natural ecosystems and also provide substantial economic impacts by pollinating plants, spreading seeds and eating pests such as moths, beetles, mosquitoes, stinkbugs and termites. Some have been documented to consume as much as 85 percent of their body weight in insects every night – and bats can weigh anywhere from an ounce and a half to north of two pounds.

“Such voracious foraging on insects has definite economic impacts, especially for agricultural production,” he explained. “More than 100 million Brazilian free-tailed bats can fly nightly from caves and highway structures, like bridges and culverts, eating up all kinds of crop pests.”

In Texas’ Winter Garden Region southwest of San Antonio, a single Brazilian free-tailed bat will eat 20 insects a night. That translates to two cents per bat, per night, of ecosystem services as farmers do not need to apply additional pesticides to achieve the same yield of cotton. When extrapolated across that region, it translates to an annual “agro-economic value” on cotton ranging from $121,000 to more than $1.72 million. That’s compared to the total value of the crop in this region of $4.6 million to $6.4 million per year.

To obtain firm numbers on the economic benefits bats provide Texas and how bridge structures contribute to that benefit, the Texas DOT and Texas A&M University are in the midst of a three-year field study expected to last through May 2021 – though, due to the COVID-19 pandemic, that study may need to be extended as stay-at-home orders has shelved the agency’s field research for two months.

“Finding places to hang during the day can be a critical limiting factor for many of these temperate bat species,” Robertson pointed out. “This is why learning more about how and why bats interact with our bridges is important to the distribution and abundance of these important species.”

He said that, of the 33 species of bats that live in Texas, 18 have been documented and six potentially use Texas DOT highway structures as day roosts.

Based on several scattered records, a number of different bat species use bridges and culverts statewide in summer and winter, with studies of sites and species combinations indicating that many highway structures house more than 1,000 bats. 

“This sample is undoubtedly an underestimate of highway structure roost use in the state, but currently the frequency of this bat-highway structure interaction is unknown,” Robertson noted. That’s why Texas DOT began this study in partnership with Texas A&M; conducting a systematic inventory of bridges and culverts in the state to compare sites that have bats and those that don’t so experts can find what attracts bats to these structures.

Current research indicates that culverts that cross divided highways usually range about 200 to 400 feet long and are about 5 to 10 feet underground; creating “thermal qualities” that simulate the thermal qualities of caves, which could be a factor in the bat’s preference. By contrast, bridges provide numerous nooks, crannies and expansion grooves that offer tight spaces for bats to roost in.

A previous study by researchers at Boston University compared the development of Brazilian free-tailed pups raised in a cave to those raised under a bridge and found that the increased temperature of those bridges during the spring and summer resulted in pups that developed faster, weaned quicker, and had larger body sizes than those in a cave.

Undoubtedly, not all bridges or culverts are used by bats, thus Robertson hopes that Texas DOT’s ongoing study will help better illuminate the factors that attract bats to nest in them. “Better information on which bridges serve as important roosts for bats will also be extremely useful for the planning and timing of maintenance and construction of highway infrastructure,” he said.

Part 2 of this story will examine the work New Mexico DOT is doing to make its bridge structures more “bat friendly.”

ETAP Podcast: Minnesota DOT’s Margaret Anderson Kelliher

In this episode of the Environmental Technical Assistance Program or ETAP podcast, host Bernie Wagenblast interviews Margaret Anderson Kelliher, commissioner of the Minnesota Department of Transportation, about her state’s perspectives on environmental sustainability.

Anderson Kelliher, who serves as chair of the American Association of State Highway and Transportation Officials Committee on the Environment and Sustainability, explains on the podcast that Minnesota looks for the “triple bottom line” when evaluating sustainability: how sustainability efforts affects the health of people, how it impacts the environment, and how it impacts the economy.

To listen to this podcast episode, click here.

New Jersey DOT’s Role in State Transportation Electrification Plan

New Jersey Governor Phil Murphy (D) has set forth an aggressive goal of achieving 100 percent clean energy by 2050 for the state – and the New Jersey Department of Transportation will play a key role in helping attain that goal.

The agency is part of a broad statewide transportation electrification effort in line with the Rejoining the Regional Greenhouse Gas Initiative or RGGI; a multi-state, market-based program that establishes a regional cap on carbon dioxide or CO2 emissions.

In mid-April, the governor announced that RGGI auction proceeds will provide $80 million each year to programs that reduce greenhouse gas emissions, with a new, more all-inclusive Energy Master Plan outlining several state investment strategies that aim to electrify New Jersey’s transportation sector. 

Along with the Master Plan, the RGGI Strategic Funding Plan details how to move toward the goal of a greener transportation system. New Jersey’s plan for its RGGI revenue is designed to support legislation signed in January that calls for the state to have 330,000 registered electric vehicles or EVs by 2025 and 2 million by 2040. It also plans for 400 fast charging stations at 200 locations along major highways and communities by 2025.

To that end, the New Jersey DOT and several other state agencies –  NJ TRANSIT, the New Jersey Board of Public Utilities, the Department of Environmental Protection, the Department of Community Affairs, the Department of Labor and Workforce Development, and the Economic Development Authority – will work together within their respective areas to achieve the RGGI’s strategic goals. 

The specific strategies laid out for the New Jersey DOT within the plan include:

  • Promoting the use of the Logo Sign Program and Tourist-Oriented Directional Signing or “LOGOS” program to display the locations of EV charging stations on blue state highway exit signs. The state will also work collaboratively with local governments on transportation planning and land use/housing planning that will enable multi-modal transportation and EV-ready infrastructure.
  • Working to prioritize multi-modal accommodations in projects located in low- and moderate-income and environmental justice communities to promote more pedestrian and bicycle traffic as those two modes are part of the RGGI’s emission reduction strategies.
  • Looking at re-evaluating “Level of Service” metrics that measure the quality of transportation services and traffic flow and develop plans to mitigate congestion and reduce idling time for vehicles. 
  • Working with local governments to promote implementation of “Complete Streets” policies in municipalities, possibly with additional grants and incentives. As part of these efforts, the New Jersey DOT and NJ TRANSIT will continue to lead a multi-agency “Smart Growth” program called the Transit Village Initiative, which helps municipalities redevelop or revitalize their downtowns into dense communities within a half-mile of transit centers.
  • Deploying Transportation Systems Management & Operations or TSMO strategies to relieve road congestion through signal optimization technology; an effort funded via the federal Congestion Mitigation and Air Quality program to make traffic patterns more efficient and further reduce idling.

Yet even as New Jersey begins moving towards electrifying its transportation sector, the unintended consequences of funding shortages must also be considered.

The draft fiscal year 2020 New Jersey Transportation Capital Program, which funds both the New Jersey DOT and NJ TRANSIT for a total of $3.679 billion, depends on motor fuels tax revenues for funding – already significantly reduced due to the impact of the COVID-19 pandemic. As New Jersey encourages use of electric-powered vehicles, the state is also considering a replacement for lost fuel tax revenue and is participating in the I-95 Coalition Mileage Based User Fee study to see how such fees would affect different communities and how they would be collected.

FEMA Issues COVID-19/Hurricane Response Guidance

The Federal Emergency Management Agency has issued a 59-page document that provides Federal, state, local, tribal, and territorial or SLTT officials – along with those of private sector and non-governmental organizations (NGO) – guidance on how to respond to both the COVID-19 pandemic and hurricanes simultaneously.

“As SLTT partners continue to prepare for hurricane season and other emergent incidents, emergency managers should review and adjust existing plans – including continuity of operations (COOP) plans – to account for the realities and risks of COVID-19 in their prioritization of life-saving and life-sustaining efforts,” FEMA said in the document.” All reviews and adjustments to plans should factor-in FEMA’s planned operational posture, social distancing measures, CDC [Centers for Disease Control] guidance, and SLTT public health guidance.”

To ensure that operational decisions are made at the lowest level possible, FEMA is organizing to prioritize resources and adjudicate accordingly, if needed:

  • At the incident level, Federal Coordinating Officers (FCO – in consultation with regional Administrators – will work to address incident requirements using available resources. FCOs will proactively manage and identify risks and communicate new requirements to Regional Response Coordination Center or RRCCs as they arise.
  • At the regional level, the RRCCs will coordinate with FEMA personnel deployed to SLTT emergency operation centers and adjudicate resource requests until operational control is ready to be transitioned to the FCO at the incident level, when designated, and will adjudicate resources within their area of operation and coordinate with other RRCCs and the National Response Coordination Center (NRCC) as required.
  • At the national level, the NRCC will coordinate with the regions on requirements and adjudicate resources to address national priorities.

Environmental News Highlights – June 3, 2020

A roundup of headlines curated for state transportation environmental professionals


EPA Narrows States’ Veto Power Over Infrastructure Projects – Bloomberg Law (see Federal Register Notices below)

23 states sue Trump to keep California’s auto emission rules – Associated Press

Injunction Sought Against Water Rule – Progressive Farmer

Colorado files lawsuit defending streams, wetlands – Conejos County Citizen

Energy & Sustainability Washington Updates – June 2020 – National Law Review

At last, a climate policy platform that can unite the left – Vox

Lawsuit Launched to Fight Trump EPA’s Delay in Reducing Sulfur Dioxide Air Pollution – Center for Biological Diversity (Press release)

Big Oil loses appeal, climate suits go to California courts – Associated Press

Senate Chairman Roger Wicker Unveils Rural Transportation Bill – Transport Topics


Enlisting Science and Technology in the Fight Against COVID-19 – and the Ongoing Struggle for Sustainable Development – National Academies

Oh No, Here Comes the Transportation Hellscape – New York Times (subscription)

Supporting commuters returning to worksites during covid-19 – Association for Commuter Transportation (Report)

Democrats Push Pandemic Aid, Highlight Infrastructure Package – Transport Topics

The Pandemic Cut Down Car Traffic. Why Not Air Pollution? – NPR

How to Safely Travel on Mass Transit During Coronavirus – CityLab


Heber Wild Horse plan development reaches milestone – White Mountain Independent (Arizona)


Building Highways and Preserving the Environment – Transfers (Report)

What Role can Infrastructure Play in the COVID-19 Recovery Effort? – Novogradac (Commentary)

Managed Retreat in the Face of Climate Change, Part 2 – CleanTechnica

Sustainability vs. Conservation: Key Similarities and Differences – Conservation Folks

Repeated Hurricanes Reveal Risks and Opportunities for Social-Ecological Resilience to Flooding and Water Quality Problems – American Chemical Society (Report)

A Climate for Reading: A Field Guide to Climate Anxiety – Climate in Emergency (Blog)


Study Examines COVID Shutdowns and Air Quality in Cities Worldwide – The George Washington University

Why We Must Close Polluting Urban Power Plants – US News and World Report (Commentary)

Cutting Air Pollution Is Crucial to Avoiding Second COVID-19 Peak, Reveals New Report – Interesting Engineering


Chelsea and East Boston deserve true transit equity – CommonWealth


With Summer Heat Waves, Hurricanes, and Flooding on the Horizon, Disaster Responders Grapple with Planning for Extreme Weather in the Time of COVID-19 – National Academies

The Tragedy of the Compost – Scientific American (Opinion)

Road markings can be ‘microplastics risk’ – new report – ITS International

When States Get Serious About Phasing Out Natural Gas – JD Supra

Final Report: Oil and Gas Extraction Wastewater Management – EPA (Report)

Aera retreats from coastal project – Bakersfield Californian


Uncovering Our Ancient Past – Archaeologist employs total stations to create photorealistic 3D GIS models – American Surveyor

Great Falls group, VDOT, Park Service collaborate on traffic hot-spot – InsideNoVa

State Parks Releases Final Scoping Document for Draft Historic Preservation Plan and Generic Environmental Impact Statement – New York State Office of Parks, Recreation and Historic Preservation (Press release)

How to Detect the Distortions of Maps – CityLab

‘Plano did not just fall out of the sky:’ Why preserving the city matters – Plano Star Courier


How mobility startups can help authorities fix public transport after the pandemic – Urban Mobility Daily

Alaskans want to ride. But a pandemic bicycle boom is making supplies scarce. – Alaska Public Media

Atlanta Ordinance Establishes New Permit Structure For Micro-Mobility Companies – WABE

Uber destroys thousands of bikes and scooters – BBC News


Forecasting through COVID-19 will be crucial for the future of transportation – TRB NCHRP

Best Workplaces for Commuters Announces Telework Certificate Program – Yahoo Finance


EPA Issues Final Rule that Helps Ensure U.S. Energy Security and Limits Misuse of the Clean Water Act – EPA (Press release)

Endangered and Threatened Species; Receipt of Incidental Take Permit Application and Habitat Conservation Plan for the Proposed Rooney Ranch Wind Repowering Project, Alameda County, California; Availability of Draft Environmental Assessment – Fish and Wildlife Service (Notice)

Tribal Transportation Self-Governance Program USDOT (Final Rule)