Ecology 101: Protecting Wildlife from Transportation

Wallis Annenburg Wildlife Crossing | Photo: Courtesy of the National Wildlife Federation

(Photo: Courtesy of the National Wildlife Federation)


The Wallis Annenberg Wildlife Crossing in Agoura Hills, California, which will soon be under construction, is unprecedented in its size, cost, and primary purpose. Estimated to cost $90 million, it is the first major wildlife over-crossing primarily aimed at bringing genetic diversity to isolated animal populations rather than preventing roadkills—though it will do that, too.

The crossing, also known as the Liberty Canyon Wildlife Crossing, will be an overpass covered with vegetation, spanning ten very busy lanes of US Highway 101. It will allow mountain lions and other species to cross between the Simi Hills to the north and the Santa Monica Mountains to the south. Without this crossing, the mountain lion populations in the area would likely disappear in the next few decades because of inbreeding, vehicle strikes, and limited space to escape from wildfires.

Traffic Light and Noise

The planned crossing features design elements that will encourage mountain lions and other species that are sensitive to light and noise to actually use it. Barriers and berms will be built to reduce the amount of traffic-generated noise and light that reaches the areas that animals will use to approach the crossing. Three of our research projects at the Road Ecology Center on roadway light and noise helped influence this design. These projects were supported through state (SB1) and federal (USDOT) funds to the UC Davis Institute of Transportation Studies and the National Center for Sustainable Transportation, respectively. 

In the first of our related projects, we found that wildlife crossings are used by larger proportions of nearby, light- and noise-sensitive animal species if the crossings are comparatively dark and quiet. Our second study showed that the different behaviors among animal species in response to traffic noise and light determined how much they used wildlife crossings with varying traffic disturbance conditions. In the third study, we investigated ways of mitigating light and noise near the Wallis Annenberg crossing and a proposed over-crossing for I-15, near Temecula, California. First we found that light and noise from traffic could be detected more than 100 meters away from the highway in the animal approach zones of both crossings. We then used 3D-design software and traffic-noise modelling software to show that changing the configuration of barriers and berms near the crossings could reduce the traffic noise and light in the approach zones (Figure). Based on the results, we made recommendations to the designers to increase the chance that wildlife will approach the crossings.

Noise glare mitigation

Figure: Noise and glare mitigation in the approach zone to the crossing. (A) Typical approach to crossing structure without noise and light abatement. (B) Quiet and dark paths created by excavating and redistributing landscape materials (tan areas) and adding barriers along the highway.

The Need for Fencing and Crossings

Every year, more than 7,000 vehicle collisions with large, wild animals (e.g., deer, black bear) are reported in California, according to our California Roadkill Observation System (, and this is likely a significant undercount. For example, State Farm Insurance Co. estimates that there are upwards of 20,000 claims/year for deer-vehicle collisions in California. Not only can these crashes lead to loss of human life, property, and animal life, they can also affect the balance of ecosystems. 

One way to slow the decline of wildlife species is by lowering direct and indirect mortality from traffic. We know that we can reduce the number of vehicle collisions and alleviate genetic isolation with simple tools: 1) traffic calming and reduction, 2) fencing alone, and 3) fencing combined with wildlife crossing structures. Research done in California by the Road Ecology Center has shown where wildlife crossings and fencing are most needed and could provide greater economic benefits than their cost ( The state is already home to more than 100 wildlife crossings, used by a wide range of reptile, amphibian, and mammal species. But there is a grave need for at least ten times as many. 

Policy Environment

In the past few years, public support for wildlife crossings has grown significantly. Knowledge and awareness of crossings has spread from research scientists, to transportation planners and engineers, to the wider world. But policies and related budgets remain inadequate to the needs. Two Legislative efforts reflect this picture. 

First, the 2021 Federal Bipartisan Infrastructure Law initially authorized $350 million for new wildlife crossings. Ultimately, however, Congress appropriated $0 of the $350 million for crossings. Second, California Assembly Bill (AB) 2344 initially required the Department of Fish and Wildlife and Caltrans (the California Department of Transportation) to investigate areas that are essential to wildlife movement and habitat connectivity, to develop a plan to address these areas, and for Caltrans to implement 10 crossing structures per year. This last and strongest requirement was supported by hunting and environmental groups, but was recently removed from the bill. Although compromise of environmental legislation is an all-too-common occurrence in California, the future will tell whether this critical requirement will be negotiated back into the bill. 

In California, Road Ecology Center research shows that wildlife-vehicle collisions cost the state upwards of $250 million per year. While the state’s transportation budget is $20-25 billion per year, Caltrans has claimed that only two to three wildlife crossings are built per year in California, which, at most, would account for about 0.1% of the annual transportation budget. Yet, surveyed taxpayers consistently report that they would be willing to pay more taxes in order to protect wildlife. And state policy may finally be starting to reflect this outlook. SB 790, signed by Governor Newsom in October 2021, included $61 million for building wildlife crossings, $7 million of which was allocated for the Wallis Annenberg crossing. 

In sum, we know where to build wildlife crossings and fences; research is improving the effectiveness of these tools; and we can approximate their cost and benefits. We have a lot of information for decision support on how to address habitat fragmentation, wildlife deaths, vehicle accidents, and the cost to humans and nonhuman animals. While the policy and transportation planning response has grown significantly, we still need more from implementing transportation agencies to protect wildlife and from legislative bodies to require action and allocate more funding to make it possible.


Fraser Shilling is the director of the Road Ecology Center at the UC Davis Institute of Transportation Studies (ITS-Davis); Seth Karten is a senior writer at ITS-Davis.

Lecturers’ appointments for Academic year 2022-2023

Temporary positions are anticipated for lecturers in the Institute of Transportation Studies (ITS) under the umbrella of the Civil and Environment Engineering Department. A list of courses that may be available during 2022-2023 academic years is attached. An updated list is available on the department website at Courses will be conducted in person on the main UC Davis Campus in Davis, CA.

Appointment Date: Several appointments may be made each year. A selected candidate will be assigned only one course in any quarter. Service dates are:

Fall Quarter 2022: September 19, 2022 – December 31, 2023
Winter Quarter 2022: January 1, 2023 – March 31, 2023
Spring Quarter 2022: April 1, 2023– June 30, 2023

Duties and Responsibilities: Teach one or more lecture and/or laboratory courses in the Department of Civil and Environmental Engineering during the academic year but not more than a single course in any quarter.

To apply please use the link: Applicants can submit their applications from 5/13/2022-6/12/2022.

Python Programmer for Model-building project

We are looking for a post-doc or academic researcher with extensive experience in software development and programming in Python, to work on a project building a model to estimate the benefits of air quality and climate policies in California. Familiarity with modeling emissions, air-quality, and health impacts is helpful.

There are three main programming tasks:

1) Processing large databases on emissions and air-quality into a 4km x 4km grid for the state of California. This includes data processing into desired formats, data entry, quality control check, and more. This requires extensive experience with very large, complex data sets. We will provide the data, or access to the data, and the methods.

2) Programming the economic and scientific functions for air dispersion models, atmospheric chemistry, health-impact (dose-respone) functions, and so on. This requires writing iterative loops, calling data, and quality control, as well as writing the actual functions. We will provide the complete methods — i.e., formulas — in a Word document.

3) Developing a browser-based graphical user interface (GUI) for managing inputs and outputs for the modeling system. We have started on a rudimentary sample. We will provide user requirements, desired inputs and outputs, graphical requirements, etc. This requires near expert-level experience with GUIs.

The programmer will work under close supervision of Dr. Delucchi. We have funding for 6-12 months of work, depending on experience and salary, beginning in Spring 2022.


Mark Delucchi
Research Scientist
Energy Systems, Economics, and Environmental Assessment
UC Davis and UC Berkeley

High Road Jobs for Transportation Policy and Research Manager

Join Our Team!

Now accepting applications for High Road Jobs for Transportation Policy and Research Manager at ITS-Davis.

The High Road Jobs (HRJ) for Transportation Policy and Research Manager will consult across the University of California Institute of Transportation Studies (UC ITS) to support major research programs and initiatives using their subject-matter knowledge of jobs and labor issues and needs for transportation. They will help advance the University’s missions of public service (bring UC knowledge to the public and public policy) and education (teaching stakeholders and engaging with external organization).

The HRJ Policy and Research Manager will contribute directly to the research and policy engagement activities of the UC ITS Resilient and Innovative Mobility Initiative (RIMI) as lead high road jobs advisor. The HRJ Policy and Research Manager will also collaborate with the UC Davis Policy Institute for Energy, Environment and the Economy (Policy Institute), and the UC Davis Plug-In Hybrid & Electric Vehicle (PH&EV) Research Center to support multiple ongoing projects, providing expert insight into the interactions between transportation, energy, climate, and resilience policy and labor issues.

For full job description, responsibilities and requirements, please refer to the attached information and the UC Davis Careers posting.

Applications will be accepted through February 24, 2022.

Apply Today

Sustainable Freight Research Analyst

RSCH DATA ANL 3 (Sustainable Freight Research Analyst)
University of California Davis


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If you are a current employee of our organization please use the following link instead:

Database Assistant (Student Position)

Student Position: Database Assistant
Institute of Transportation Studies (ITS-Davis)

Open to UC Davis Students
Apply by February 28, 2022 through Handshake at:
Job No.: 5931974
Job Title: STDT-4

This position serves the important purpose of helping to broadcast ITS-Davis research publications, and events, making our research and activities known to the public, policymakers, researchers, students, and funders.

Job Purpose: Maintain and update research publications database; post research reports on UC’s open access library of publications (escholarship); update Institute of Transportation Studies events on the central UC Davis calendar (Trumba); and provide additional support as needed, such as social media posting, writing, content creation.

Job Description: Do you have the ability to be careful and exacting in managing and entering information into a database? Are you able to identify ways to streamline processes, such as conducting web searches and transferring the found information into a database or document files? ITS-Davis seeks a talented student assistant to help us with the vital task of keeping current our publications database, events calendar, and help plan social media strategies.

Database Management

  • Conduct online literature searches through Google Scholar (and other applications and search engines) to find publications by ITS-Davis researchers
  • Enter publication information on the ITS-Davis database; publish documents that ITS-Davis has rights to on
  • Track the above processes on internal spreadsheets.
  • Possibly identify ways to make the above processes more efficient at capturing a higher percentage of publications
  • Communicate with ITS-Davis researchers and staff regarding posting publications on the database or publishing them on escholarship

Miscellaneous (as needed)

  • Maintain postings of upcoming ITS-Davis events on the UC Davis campus calendar and ITS-Davis calendar
  • Occasionally take notes at events, write social media posts (Twitter, LinkedIn, Facebook), and track social media analytics on internal spreadsheets.
  • Occasionally assist on other communications projects, including editing and creating promotional and internal materials such charts to quantify publications and media appearances

You will be working with a collaborative team of staff and students, either remotely or in our offices on the UC Davis West Village campus, depending on the current COVID-19 regulations. The work schedule is flexible. You will work under the supervision of the Science Writer and the Senior Director of Communications.

Qualifications (Required) Necessary

  • Demonstrated experience performing precise entry of information (e.g., transferring text and numbers from a source document to the appropriate fields in a database).
  • Professional attitude and conduct, including communicating promptly and effectively with researchers, managers
  • Open to feedback and able to meet deadlines.
  • Self-initiative and the ability to troubleshoot and work independently.


  • Spreadsheet experience; tracking pending and completed tasks in a program such as Excel or Google sheets
  • Experience with or ability to learn other computer software, such as Google Drive, social media sites, Box.
  • Experience in streamlining internet searches and data entry processes
  • Interest in sustainable transportation and energy, and related policy-making and urban planning

Travel Demand and GIS Modeling Postdoc focus on EV Infrastructure

About us

The Plug-in Hybrid & Electric Vehicle (PH&EV) Research Center launched in early 2007, with the support of the California Energy Commission’s allocation of Public Interest Energy Research (PIER) funds for transportation research. The Center collaborates closely with California utilities, automakers, regulators, and other research institutions to provide the rigorous research and impartial policy analysis that are needed to meet the climate environmental and equity goals of our society.

Moving forward our research is focused on measuring, monitoring and understanding multiple aspects of the quickly evolving market for zero emission vehicles, the incentives and policy needed to meet the goals nationally and internationally, the demand for infrastructure and the energy and environmental aspects of the transition.

The program receives support from industry partners, planning agencies and research foundations, and works in close cooperation with the federally-funded National Center for Sustainable Transportation and other research programs at UC Davis. For additional information on the PH&EV Center and on ITS Davis, please see and

Position Description

The selected candidate will join a team investigating the future of mobility at the University of California, Davis. The postdoctoral researcher will work on travel behavior modeling research and will focus on developing models for electric vehicles usage and refueling locations as part of the Travel Demand Modeling and Geographical Information Systems team at the PH&EV Research Center. The position’s primary duties will be to update a system of spatial planning tools as part of a larger toolbox for planning for the installation of charging stations, to engage current projects addressing the issues of plug-in electric vehicles and consumer behaviors, and to develop knowledge and investigate topics relevant to the increased adoption and use of electric vehicles.


Candidates should have completed a doctoral degree in Civil Engineering, Transportation Planning, Computer Science, Economics, Geography, or a related field at the time of hire. Candidates with strong multidisciplinary skills covering more than one of these areas are particularly encouraged to apply. Extremely well-qualified candidates with slightly different qualifications and/or research focus might be also considered under special circumstances.

The postdoctoral researcher must be able to work collaboratively with a team ranging from undergraduate research assistants to senior research faculty. The postdoctoral researcher must also be a skilled communicator, able to write clear academic papers or briefings as well as present their research to a variety of audiences.


The postdoctoral researcher must have a deep understanding of travel behavior, travel demand modeling, GIS tools, and discrete choice modeling, including demonstrable experience in:

  • Spatial analysis using tools such as ArcGIS or QGIS.
  • Quantitative methods for data analysis using statistical software such as R, Python, STATA, JMP, or equivalent.
  • Transportation issues, particularly those related to zero-emission transportation.

In addition, the postdoctoral researcher must have excellent verbal and written English language communication skills.

Because the center’s researchers employ a range of methods to address topics relating to the purchase and use of electric vehicles, experience in one or more of the following areas would also be beneficial:

  • Latent class analysis and structural equations modeling using tools such as Latent Gold, MPlus, or equivalent.
  • Market research, forecasting, and the adoption of new technology.
  • Survey design and implementation.

Interested applicants should email their CV to Dahlia Garas,

New Recruitment: Director of the European Research Center on Transportation and Climate Policy

Under general direction of the Director for the UC Davis Institute of Transportation Studies (ITS-Davis), the Director of the European Research Center provides vision and intellectual leadership for research and outreach activities for the center. Responsible for leading all research activities including defining research directions. Independently manage and provide technical and academic direction to support administrative and academic staff. Works closely with faculty, staff and extramurally funded programs housed within ITS-Davis to enhance the visibility and impact of the Institute, including developing partnerships with a broad range of constituents in education, local state national, and international agencies and legislative bodies. Respond to emerging initiatives and optimize ITS resources in responding to research and operational needs. Provide ongoing organizational and programmatic review to continually identify opportunities for improving funding to support new center. Develop and participate in opportunities for writing contract and grant proposals in collaboration with faculty and staff in ITS.

The new hire will be expected to lead the development of the European Research Center including: Develop the strategic plan, fundraise to cover costs of the center (with initial funding from the main ITS-Davis organization); maintain oversight of the Center’s budget, hire and manage staff, set programmatic agendas and priorities, ensure programmatic compliance relative to both schedules and budgets, and execute the program. Related responsibilities will include fostering alliances between funding partners and the research program that serve the research center’s business development goals, develop a research portfolio that addresses a board variety of government, industry, and NGO needs, including leading and participating in outreach activities to educate partners on technologies and research; oversee implementation of short-and long-term staffing plans that support the mission and activities of the Center; create and deliver high quality, research programs and funding model to support the center’s operational activities via independent and collaborative research initiatives.

In addition, the new hire will be expected to lead and conduct recruitment efforts to support research which will result in scholarly publications, research reports and presentations. Oversee and support faculty, staff and students and provide operational resources and direction, while ensuring compliance with University policies and procedures. Ensure that projects and activities align with the mission of the Center and ITS in order to ensure sustainability, growth, cohesiveness and collaboration.

Applications to this position can be received by December 31, 2021, via the link:, Job number 27875.

Postdoc Researcher Position

Institute of Transportation Studies
Energy Futures Program
University of California, Davis

Supervisors: Dr. Lewis Fulton and Prof. Dan Sperling
December 2021


The UC Davis Institute of Transportation Studies, Energy Futures (EF) Program is recruiting a postdoctoral Scholar to support our efforts to develop models of the transportation systems within the United States and internationally and conduct detailed analysis using those models. Particular emphasis will be on one or more of: transitions to net-zero transportation energy systems, modeling of electric and fuel cell cars and trucks within transportation systems, and modeling hydrogen systems in the context of transportation and stationery system decarbonization. Experience is not needed in all these areas but would be a plus.

Candidates should have completed a doctoral degree in one of the fields of: Civil Engineering, Transportation Planning, Computer Science, Economics, Energy resources, Geography, Operations Research or a related field at the time of hire. Candidates should have significant experience in one or more of the following: developing and running models of national level transportation and energy systems including simulation, optimization, and/or backcasting elements; transportation systems planning; projecting future changes in systems; and understanding relevant potential policies to encourage low-carbon future systems.

Candidates with strong multidisciplinary skills covering more than one of the areas listed above are particularly encouraged to apply. Extremely well-qualified candidates with slightly different qualifications and/or research focus might be also considered under special circumstances.

Other essential qualifications include an excellent track of scientific publications; excellent English-language writing skills; ability to meet deadlines, work well with minimal direction and with a team, and produce high-quality research outputs; good time management and record-keeping. Desirable qualifications include solid presentation skills and experience with fundraising and maintaining rapport with funding agencies.

The selected candidates will join a growing team working on research on future mobility at the University of California, Davis. They will work with Dr. Fulton and other researchers in the program on projects related to modeling future transportation and energy systems in the US and internationally, including a range of topics related to new vehicle technologies, new fuels, and transportation system dynamics. Other duties commensurate with the researcher’s qualifications will also be assigned.

Screening of applications will begin immediately, and recruitment will continue until the position is filled. Interviews with applicants will be scheduled via phone or videoconference, and in-person informal interviews may be held during the TRB 2022 meeting.

We offer a competitive salary and generous benefits, including health insurance, retirement plan, vacation and sick leave, and support to a successful career in scientific research. The successful candidates will be encouraged to submit the output of their work to scientific conferences and professional meetings. Pending acceptance of the work, and funding availability, they will receive support for the attendance of these meetings.

The University of California, Davis is an Equal Opportunity/Affirmative Action employer, and applications from women and under-represented minorities are encouraged.

Applicants should submit a cover letter, curriculum vitae, copy of one selected publication and names/contact information of three references in a single PDF file to Lew Fulton: Please format the file name as {lastname_initials}_EFP_postdoc2019.pdf and include “Postdoc Search” in the subject line of the e-mail.

Energy Futures Program and UC Davis

The Energy Futures Program is a rapidly growing research and policy program in the Institute of Transportation Studies of the University of California, Davis. It grows out of the STEPS program and focuses on medium/long term transportation energy transitions for California, the US and worldwide. The program receives support from a range of government and industry partners, planning agencies and research foundations, and works in close cooperation with the federally-funded National Center for Sustainable Transportation and the other research programs at UC Davis. For additional information on the Energy Futures Program and on ITS Davis, please see and

How Providing Emissions Information Can Begin Greening Aviation

Illustration of flight schedule board with blank rows and positive or negative CO2 indicators at the end of each row

Those carefree, pre-pandemic days of hopping on a flight for a meeting or vacation without a second thought may seem like a distant memory to some of us right now. Still, air travel this fall has far exceeded that of 2020, even if it has yet to recover to pre-pandemic levels. Fairly soon, flying will almost certainly return to the upward trend that showed global air travel more than doubled from 2004-2019.

That’s a problem for the climate.

Flights accounted for about 2.5% of worldwide greenhouse gas emissions in 2019. While the federal government has announced an emissions reduction target of 20% by 2030 and a key airline industry group has recently proposed a net-zero plan, there is no firm consensus on a path to decarbonization for the aviation sector.

Can individual travelers play a role in reducing emissions?

Many climate hawks are cutting back or choosing not to fly at all. And it turns out that even when we do fly, our choices matter–different flight itineraries on the same route can vary quite a bit in the amount of greenhouse gases they generate, primarily due to the number of layovers (take-offs and landings produce a lot of emissions), the locations of the layovers, and the fuel efficiency of the aircraft. For example, a traveler heading from Sacramento, CA to Washington, DC might see a selection of flights that vary in emissions by as much as 30%.

That’s why the new emissions information you see when searching on Google Flights is so important. Our research indicates that people will use this information to choose lower-emissions flights.

Illustration of flight schedule board with blank rows and positive or negative CO2 indicators at the end of each row


How Emissions Information Can Make a Difference

In 2015 we began work on, a demo flight search website that shows the emissions of each flight as prominently as the price, labels the lowest emissions options “Your GreenFLY,” and, by default, sorts flights from lowest to highest emissions. Experimenting with GreenFLY helped us demonstrate the wide variation in emissions among flights with the same origins and destinations, especially for long cross-country or international flights.

We conducted two experiments to test whether this method of providing emissions information on available flight options would nudge travelers toward choosing lower-emitting flights. After all, someone using a flight-search website is already balancing many factors, such as when to fly, price, length of layover and perhaps a favorite airline; why not put emissions into the mix? In our studies we asked people to choose between a few flights, and we used that data to build a predictive model of how much value people put on different factors such as price, layovers, and emissions.

As most other researchers into flight choice have found, price was the most important consideration. But we also found that people were willing to pay more for a lower-emissions flight. For instance, an international flight might emit around a metric ton of carbon (1000kg); and people were willing to pay $20 more for a ticket that avoided 100kg of CO2 emissions, or about 10%. This translates to a rate (“willingness to pay”) of about $200/ton of CO2 saved, much higher than the average price of carbon offsets, which is about $3-6/ton! This surprisingly strong effect was consistent between two studies looking at different populations (one of UC Davis employees and one of more broadly recruited American travelers).

Real-World Emissions Reductions

Our studies presented travelers with hypothetical trips, and our GreenFLY site was just a demo. But now that Google Flights is using an emissions-focused interface, we will have an opportunity to see how emissions information will influence consumer behavior on a huge scale. We’re optimistic that we’ll see an impact on the travel choices of Google Flights’ many users and, possibly, on overall aviation emissions.

The possibilities are exciting. If more travel booking and search platforms follow the lead of Google and others like Kayak, Skyscanner, and Lite Flights, this could have a cascading effect. Many consumers choosing lower-carbon flights could push airlines to invest in more fuel-efficient aircraft as well as sustainable aviation fuels. Repeatedly seeing emissions information could raise traveler’s awareness of the environmental cost of flying. This may ultimately build support for emissions reduction regulations and investments in more sustainable travel alternatives.


More information on the authors’ GreenFLY research is available in an NCST ReportNCST Policy Brief, a 2021 Transportation Research Record paper, and a 2017 Design, User Experience, and Usability Conference Paper.


Angela Sanguinetti is a Research Environmental Psychologist at the UC Davis Institute of Transportation Studies and Energy & Efficiency Institute.

Nina Amenta is professor of Computer Science at UC Davis.

Mike Sintetos is Policy Director for the National Center for Sustainable Transportation (NCST) and SB1 Research Program at the UC Davis Institute of Transportation Studies.