Scholarly Work - Western Transportation Institute

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Intercity Bus Service Funding and Assessment Methodology
(University of South Florida Libraries, 2012-09) Ye, Zhirui; Kack, David; Chaudhari, Jaydeep; Ewan, Levi
The Federal Transit Administration (FTA)’s 5311(f) program requires that 15 percent of 5311 program funds given to a state be used to develop and support intercity bus (ICB) service. This 15 percent can be waived if the governor certifies that the ICB needs are being met within the state. This certification became harder to justify when FTA began requiring a more stringent consultation process before certification could be given. The objectives of this study are to learn about current practices of ICB service funding mechanisms, funds prioritization, and determination processes and strategies that promote ICB service. An assessment methodology for Montana was developed to determine whether ICB needs are being adequately met and how to allocate funds to support service. The results of this study will be valuable to other states considering developing methodologies for certification and funding allocation purposes.
Integrated adaptive design for wildlife movement under climate change
(2015-11) Lister, Nina-Marie; Brocki, Marta; Ament, Robert J.
Climate change is anticipated to alter both wildlife movement and distributions. Despite mounting evidence that wildlife-crossing infrastructure offers a reliable, physical solution to the linked problems of wildlife road mortality and habitat fragmentation, pervasive barriers - from economic to governance structures - prevent the widespread introduction of an infrastructure network. To overcome these barriers, and to cope with the challenges posed by climate change, we argue that proactive, anticipatory planning and evidence-based, integrated highway-impact mitigation strategies are needed. Specifically, wildlife-crossing infrastructure should emphasize an integrated and adaptive approach to constructing innovative, modular, and potentially moveable structures that can be transferred from one location to another as monitoring of habitats and wildlife needs indicate. Continued investment in fixed, static structures, which are typically based on engineering standards designed for traffic loads rather than wildlife movement, may prove ineffectual as habitats change in composition and location, potentially leading to associated changes in the locations of wildlife-vehicle collisions.
Wolverine behavior varies spatially with anthropogenic footprint: implications for conservation and inferences about declines
(2016-03) Stewart, Frances E.C.; Heim, Nicole A.; Clevenger, Anthony P.; Paczkowski, John; Volpe, John P.; Fisher, Jason T.
Understanding a species’ behavioral response to rapid environmental change is an ongoing challenge in modern conservation. Anthropogenic landscape modification, or “human footprint,” is well documented as a central cause of large mammal decline and range contractions where the proximal mechanisms of decline are often contentious. Direct mortality is an obvious cause; alternatively, human-modified landscapes perceived as unsuitable by some species may contribute to shifts in space use through preferential habitat selection. A useful approach to tease these effects apart is to determine whether behaviors potentially associated with risk vary with human footprint. We hypothesized wolverine (Gulo gulo) behaviors vary with different degrees of human footprint. We quantified metrics of behavior, which we assumed to indicate risk perception, from photographic images from a large existing camera-trapping dataset collected to understand wolverine distribution in the Rocky Mountains of Alberta, Canada. We systematically deployed 164 camera sites across three study areas covering approximately 24,000 km2, sampled monthly between December and April (2007–2013). Wolverine behavior varied markedly across the study areas. Variation in behavior decreased with increasing human footprint. Increasing human footprint may constrain potential variation in behavior, through either restricting behavioral plasticity or individual variation in areas of high human impact. We hypothesize that behavioral constraints may indicate an increase in perceived risk in human-modified landscapes. Although survival is obviously a key contributor to species population decline and range loss, behavior may also make a significant contribution.
Economic feasibility of safety improvements on low-volume roads
(2017-09) Al-Kaisy, Ahmed; Ewan, Levi A.; Hossain, Fahmid
This article presents an investigation into the economic feasibility of safety countermeasures along rural low-volume roads. Although these roads may be associated with higher crash risks as they\'re built to meet lower standards, crash frequencies are notably lower than those on other roadways with higher traffic exposure. Therefore, it is reasonable to expect that some conventional safety countermeasures that are proven to be cost effective on well-travelled roads may turn out to be infeasible on low-volume roads. Twenty-seven safety improvements were examined in this investigation for their economic feasibility along low-volume roads. A roadway sample of 681 miles of Oregon was used in this study. Detailed benefit-cost analyses were performed using countermeasure costs, 10-year crash data, and expected crash reductions using Highway Safety Manual methods. Around half of the countermeasures investigated were found cost-effective for implementation along low-volume roads. Further, most of the countermeasures that were found to have very high benefit-cost ratio are associated with low initial cost and many of them do not require much maintenance cost. At the other end of the spectrum, almost all roadway cross-section safety improvements were found economically infeasible due to higher associated costs relative to the expected crash reduction benefits on low volume roads.
Performance of Arch-Style Road Crossing Structures from Relative Movement Rates of Large Mammals
(2017-10) Andis, A. Z.; Huijser, Marcel P.; Broberg, Len
In recent decades, an increasing number of highway construction and reconstruction projects have included mitigation measures aimed at reducing wildlife-vehicle collisions and maintaining habitat connectivity for wildlife. The most effective and robust measures include wildlife fences combined with wildlife underpasses and overpasses. The 39 wildlife crossing structures included along a 90 km stretch of US Highway 93 on the Flathead Indian Reservation in western Montana represent one of the most extensive of such projects. We measured movements of large mammal species at 15 elliptical arch-style wildlife underpasses and adjacent habitat between April and November 2015. We investigated if the movements of large mammals through the underpasses were similar to large mammal movements in the adjacent habitat. Across all structures, large mammals (all species combined) were more likely to move through the structures than pass at a random location in the surrounding habitat. At the species level, white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) used the underpasses significantly more than could be expected based on their movement through the surrounding habitat. However, carnivorous species such as, black bear (Ursus americanus) and coyote (Canis latrans) moved through the underpasses in similar numbers compared to the surrounding habitat.
The role of social capital in traffic safety citizenship
(2018) Finley, Kari; Otto, Jay; Ward, Nicholas
Traffic safety citizenship is an emerging approach to reduce serious injuries and fatalities on our roadways. The goals of this study were to develop a model to identify beliefs and values associated with intention to engage in traffic safety citizenship behaviors with strangers and to explore the role of an individual's perception of social capital in this model. This study focused on two safety citizenship behaviors: intervening as a driver to ask a passenger to wear a seat belt and intervening as a passenger to ask a driver to stop reading or typing on a cell phone while driving. Results showed that one-third of the respondents had been in a situation to intervene with a stranger in the past twelve months. Of those in a situation to intervene, most reported they did not always intervene. They were more likely to intervene about a seat belt than about texting. Intention to intervene was significantly correlated with intervening behavior, and linear regression models revealed that perceived control was the dominant component most predictive of intention to intervene. Social capital did not directly predict intention to intervene but was predictive of the perceived injunctive norm and the perceived descriptive norm, which were both predictive of intention. Results of the study provide a better understanding of the beliefs and values associated with the intention to engage in traffic safety citizenship behaviors and the role of social capital to facilitate engagement in these behaviors. Recommendations to increase safety citizenship behaviors are provided.
Bicycle & Pedestrian Infrastructure Improvements Realized in Communities of Less Than 10,000 People: Final Report
(2018-12) Villwock-Witte, Natalie
The objective of this study was to better define underlying factors that have allowed communities of less than 10,000 people within three states (Maine, Minnesota, and New Hampshire) to successfully implement bicycle and pedestrian infrastructure. These factors were defined by first conducting a thorough literature review along with general information gathering, as there is little published knowledge about communities of less than 10,000 people. Based on the information collected and synthesized from the literature review, interview questions were developed to ask leadership (planners, town administrators, elected officials) and advocates within communities of less than 10,000 people. Interviewees were targeted from two types of communities: those that have successfully implemented bicycle and pedestrian infrastructure, and those that have shown potential to implement bicycle and pedestrian infrastructure. As an outcome of a series of in-depth interviews with key members in chosen communities, the following characteristics surfaced as being influential in whether or not bicycle and pedestrian infrastructure can be found within these smaller communities within Maine, Minnesota, and New Hampshire: • The speed limits, particularly adherence to speed limits within a community, • Having many champions for bicycle and pedestrian modes, • Having programs to teach or support bicycle and/or pedestrian modes, • Having bicycle and/or pedestrian groups, and • The community approval process.
Short and narrow roads cause substantial impacts on wildlife
(2019) Magioli, Marcelo; Bovo, Alex A. A.; Huijser, Marcel P.; Abra, Fernanda D.; Miotto, Renata A.; Andrade, Victor H. V. P.; Nascimento, Adriana M.; Martins, Maisa Z. A.; Micchi de Barros Ferraz, Katia M. P.
Short and narrow roads are generally overlooked when assessing road impacts on biodiversity. However, these roads bisect natural environments and may cause significant impacts on wildlife in local scale. Thus, we monitored roadkills along a short two-lane road (CPM road) in Southeastern Brazil and propose mitigation strategies to reduce wildlife mortality. We monitored roadkilled vertebrates along 5 km of CPM road from 2010 to 2016 and we also compiled data from previous studies along the same road. We conducted a hotspot analysis to identify CPM road areas with significant roadkill aggregation. We recorded 77 roadkilled vertebrates from 14 taxonomic groups along the CPM road. Mammals were the most frequently recorded group (91% of roadkills), which represented 56% of all medium- and large-sized mammal species known to occur in the study area. We identified three roadkill hotspots along the CPM road. Two of them were located at two stream crossings, where the road cut across the associated riparian forests, and the other was at a road section with water drainage from a pond, also connected to a riparian forest. These riparian forests are part of the remaining natural habitat that provides connectivity between the forest remnants in the landscape, and therefore, for wildlife. Our results showed that even short and narrow roads can have considerable roadkill, which may have severe effects for wildlife on a local scale. The results stress the need to carefully look at these types of roads and propose measures to reduce impacts. We propose the creation of safe crossing opportunities in the hotspot zones combined with wildlife fencing to keep the animals off the road and guide them towards the safe crossing opportunities.
Pay or prevent? Human safety, costs to society and legal perspectives on animal-vehicle collisions in Sao Paulo state, Brazil
(2019-04) Abra, Fernanda D.; Granziera, Beatriz M.; Huijser, Marcel P.; de Barros Ferraz, Katia Maria Paschoaletto Micchi; Haddad, Camilla M.; Paolino, Roberta M.
Direct road mortality and the barrier effect of roads are typically identified as one of the greatest threats to wildlife. In addition, collisions with large mammals are also a threat to human safety and represent an economic cost to society. We documented and explored the effects of animal-vehicle crashes on human safety in São Paulo State, Brazil. We estimated the costs of these crashes to society, and we summarized the legal perspectives. On average, the Military Highway Police of São Paulo reported 2,611 animal-vehicle crashes per year (3.3% of total crashes), and 18.5% of these resulted in human injuries or fatalities. The total annual cost to society was estimated at R$ 56,550,642 (US $ 25,144,794). The average cost for an animal-vehicle crash, regardless of whether human injuries and fatalities occurred, was R$ 21,656 (US $ 9,629). The Brazilian legal system overwhelmingly (91.7% of the cases) holds the road administrator liable for animal-vehicle collisions, both with wild and domestic species. On average, road administrators spent R$ 2,463,380 (US $ 1,005,051) per year compensating victims. The logical conclusion is that the Brazilian legal system expects road administrators to keep animals, both wild and domestic species, off the road. We suggest an improved coordination between the laws that relate to animal-vehicle collisions and human safety, and the process for environmental licenses that focuses on reducing collisions with wildlife and providing habitat connectivity. In addition, we suggest better management practices, raising awareness and social change with regard to abandoned domesticated animals including horses, cattle, and dogs. This should ultimately result in a road system with improved human safety, reduced unnatural mortality for both domestic and wild animal species, safe crossing opportunities for wildlife, and reduced monetary costs to society.
Incorporating wildlife passive use values in collision mitigation benefit-cost calculations
(Nevada Department of Transportation, 2019-09) Duffield, John; Neher, Chris
This document is a task report for a larger Wildlife Vehicle Collision (WVC) Reduction and Habitat Connectivity pooled fund study. It addresses the potential use of passive use economic values for wildlife to inform the mitigation of wildlife-vehicle collisions. Passive use, also known as non-use values, are the values individuals place on the existence of a given animal species or population as well as the bequest value of knowing that future generations will also benefit from preserving the species. This report provides a summary of the current literature of wildlife passive use value estimates and provides per-animal passive use values for selected species and populations. Additionally, an example of applying these values to a Montana road segment is outlined. Finally, a discussion of regional economic impacts of mitigation structure spending is outlined.
Valuing Wildlife Crossings and Enhancements for Mitigation Credits
(National Academy of Sciences, 2020-01) Samanns, Edward; Baigas, Phil; Ament, Robert; Huijser, Marcel
This report summarizes the activities conducted as part of National Cooperative Highway Research Program (NCHRP) 25-25, Task 117, Valuing Wildlife Crossing and Enhancements for Mitigation Credits. Mitigation crediting could provide a valuation approach that state DOTs could use to promote the construction of wildlife crossings and other enhancements to mitigate transportation project impacts. The two objectives of this research are to: • Collect and synthesize current information on valuation methods, metrics, criteria for credit development, and crediting mechanisms used by state DOTs and their partners for calculating and applying mitigation and advance mitigation credits for wildlife connectivity improvements. • Identify existing and potential quantitative methods and approaches for establishing the mitigation values of wildlife overpasses, underpasses, bridges, and culverts for habitat connectivity, and how that value is translated to mitigation credits. The full report can be found at: http://www.trb.org/Main/Blurbs/180347.aspx
An estimate of wild mammal roadkill in Sao Paulo state, Brazil
(Elsevier BV, 2021-01) Abra, Fernanda Delborgo; Huijser, Marcel Pieter; Magioli, Marcelo; Bobo, Alex Augusto Abreu; de Barros Ferrraz, Katia Maria Paschoaletto
Roadkill estimates for different species and species groups are available for many countries and regions. However, there is a lack of information from tropical countries, including from Latin America. In this study, we analyzed medium and large-sized mammal roadkill data from 18 toll road companies (TRC) in São Paulo State (6,580 km of monitored toll roads), Brazil. We extrapolated these roadkill numbers to the entire system of major paved roads in the State (36,503 km). The TRC collected mammal-road- mortality data both before (2-lanes) and after (4-lanes) road reconstruction. We used the “before” data from the TRC to estimate annual mammal-road-mortality along 2-lane roads that remained public roads. Combined with the data for the new 4-lane highways, this allowed us to estimate annual mammal road mortality for all the paved roads in the State. During 10 years of roadkill monitoring along toll roads, a total of 37,744 roadkilled mammals were recorded, representing a total of 32 medium to large-sized mammal species (average number of roadkilled individuals/year = 3,774 ± 1,159; min = 1,932; max = 5,369; 0.6 individuals roadkilled/km/year). Most roadkilled species were common generalists, but there were also relatively high roadkill numbers of threatened and endangered species (4.3% of the data), which is a serious conservation concern. Most of the roadkill was reported occurred during the nocturnal period (66%, n = 14,189) and in the rainy months (October–March) (55%, n = 15,318). Reported mammal roadkill tended to increase between 2009 and 2014 (R2 = 0.614; p = 0.065), with an average increase of 313.5 individuals/year. Extrapolation of the results to the entire São Paulo State, resulted in an average estimate of 39,605 medium and large-sized mammals roadkilled per year. Our estimates of the number of roadkilled individuals can be used as one of the input parameters in population viability analyses to understand the extinction or extirpation risk, especially for threatened and endangered species.
Inference of Transit Passenger Counts and Waiting Time Using Wi-Fi Signals
(Western Transportation Institute, 2021-08) Videa, Aldo; Wang, Yiyi
Passenger data such as real-time origin-destination (OD) flows and waiting times are central to planning public transportation services and improving visitor experience. This project explored the use of Internet of Things (IoT) Technology to infer transit ridership and waiting time at bus stops. Specifically, this study explored the use of Raspberry Pi computers, which are small and inexpensive sets of hardware, to scan the Wi-Fi networks of passengers’ smartphones. The process was used to infer passenger counts and obtain information on passenger trajectories based on Global Positioning System (GPS) data. The research was conducted as a case study of the Streamline Bus System in Bozeman, Montana. To evaluate the reliability of the data collected with the Raspberry Pi computers, the study conducted technology-based estimation of ridership, OD flows, wait time, and travel time for a comparison with ground truth data (passenger surveys, manual data counts, and bus travel times). This study introduced the use of a wireless Wi-Fi scanning device for transit data collection, called a Smart Station. It combines an innovative set of hardware and software to create a non-intrusive and passive data collection mechanism. Through the field testing and comparison evaluation with ground truth data, the Smart Station produced accurate estimates of ridership, origin-destination characteristics, wait times, and travel times. Ridership data has traditionally been collected through a combination of manual surveys and Automatic Passenger Counter (APC) systems, which can be time-consuming and expensive, with limited capabilities to produce real-time data. The Smart Station shows promise as an accurate and cost-effective alternative. The advantages of using Smart Station over traditional data collection methods include the following: (1) Wireless, automated data collection and retrieval, (2) Real-time observation of passenger behavior, (3) Negligible maintenance after programming and installing the hardware, (4) Low costs of hardware, software, and installation, and (5) Simple and short programming and installation time. If further validated through additional research and development, the device could help transit systems facilitate data collection for route optimization, trip planning tools, and traveler information systems.
Incorporating deer and turtle total value in collision mitigation benefit-cost calculations
(Nevada Department of Transportation, 2021-09) Duffield, John; Neher, Chris
This document is a task report for a larger Wildlife Vehicle Collision (WVC) Reduction and Habitat Connectivity pooled fund study. It addresses the potential use of passive use economic values for wildlife to inform the mitigation of wildlife-vehicle collisions. Passive use, also known as non-use values, are the values individuals place on the existence of a given animal species or population as well as the bequest value of knowing that future generations will also benefit from preserving the species. This report describes a pilot survey and study of willingness to pay by Minnesota households to pay for exclusionary fencing and passage structures to reduce vehicle/animal collisions in the state. The species of focus were deer and turtles. The study found strong support for fencing and passage structures, and statistically significant willingness to pay increased taxes to support their construction.
A comparison of elk-vehicle collisions patterns with demographic and abundance data in the Central Canadian Rocky Mountains
(Nevada Department of Transportation, 2021-09) Gunson, Kari E.; Clevenger, Anthony P.; Ford, Adam T.
This study looks at the patterns and processes of elk-vehicle collisions in the Central Canadian Rocky Mountains and analyses the demographic structure of the wildlife involved in the collisions. Key findings included: males and subadults were more prone to elk-vehicle collisions; collisions occur more commonly in the fall season; all healthy elk are susceptible to vehicle collisions; the magnitude of elk collision was negatively correlated to traffic volumes, because abundance of elk greatly decreased during the study period; and elk abundance was the primary driver influencing occurrence of collisions over time. Collectively, these results will help inform the design of mitigation measures targeting the most vulnerable demographics of a population, i.e. subadults and male elk in the fall.
On the Road Without a Map: Why We Need an “Ethic of Road Ecology”
(Frontiers Media SA, 2021-11) Moore, Lauren J.; Arietta, A. Z. Andis; Spencer, Daniel T.; Huijser, Marcel P.
Over the past two decades, our knowledge of the ecological impacts of roads has increased rapidly. It is now clear that the environmental effects of transportation infrastructure are inextricable from transportation benefits to economic, social, and cultural values. Despite the necessity of optimizing these multiple values, road planners, scientists, and practitioners have no established methodology or pluralistic approach to address growing ethical complexities. We articulate five ethical issues that could be addressed by developing an ethic of road ecology in order to facilitate the identification, reasoning, and harmonization of ethical dimensions of road planning and development. This inquiry into road ecology can draw lessons from existing applied ethics, such as in ecological restoration and urban planning, to build a narrative that is informed by both science and ethics. We illustrate five ethical issues presented through case studies that elaborate on the motivations, responsibilities, and duties that should be considered in ethically and scientifically complicated road building decisions. To address these issues, we encourage the development of a code of ethics, dedicated intellectual forums, and practical guidance to assist road planners, and more broadly transportation practitioners, to resolve complex ethical quandaries systematically. We hope this perspective encourages conversation for a holistic yet pragmatic approach to this applied ethics problem, while also assisting responsible parties as they navigate difficult moral terrain.
Animal Vehicle Collision Reduction and Habitat Connectivity Pooled Fund Study – Literature Review
(Nevada Department of Transportation, 2021-12) Huijser, M.P.; Ament, Robert J.; Bell, M.; Clevenger, A. P.; Fairbank, E.R.; Gunson, K.E.; McGuire, T.
This report contains a summary of past research and new knowledge about the effectiveness of mitigation measures aimed at reducing animal-vehicle collisions and at providing safe crossing opportunities for wildlife. The measures are aimed at terrestrial large bodied wild mammal species, free roaming large livestock species (e.g. cattle, horses), free roaming large feral species (e.g. “wild” horses and burros), and small animal species (amphibians, reptiles, and small mammals). While mitigation is common, it is best to follow a three-step approach: avoidance, mitigation, and compensation or “off-site” mitigation. If reducing collisions with large wild mammals is the only objective, the most effective measures include roadside animal detection systems, wildlife culling, wildlife relocation, anti-fertility treatments, wildlife barriers (fences),and wildlife fences in combination with wildlife crossing structures. If the objectives also include maintaining or improving connectivity for large wild mammals, then wildlife barriers (fences) in combination with wildlife crossing structures are most effective. Measures for large domestic mammal species are largely similar, though for free roaming livestock there are legal, moral and ethical issues. For small animal species, temporary or permanent road closure and road removal are sometimes implemented, but barriers in combination with crossing structures are the most common.
A before-after-control-impact study of wildlife fencing along a highway in the Canadian Rocky Mountains
(Nevada Department of Transportation, 2022-02) Clevenger, Anthony P.; Ford, Adam T.
Wildlife exclusion fencing has become a standard component of highway mitigation systems designing to reduce collisions with large mammals. Past work on the effectiveness of exclusion fencing has relied heavily on control-impact (i.e., space-for-time substitutions) and before-after study designs. These designs limit inference and may confound the effectiveness of mitigation with co-occurring process that also change the rate of collisions. We used a replicated before-after-control-impact study design to assess fencing effectiveness along the Trans-Canada Highway in the Rocky Mountains of Canada. We found that collisions declined for common ungulates species (elk, mule deer and white-tailed deer) by up to 96% but not for large carnivores. The weak response of carnivores is likely due to combination of fence intrusions and low sample sizes. When accounting for background changes in collision rates observed at control sites, naïve estimates of fencing effectiveness declined by 6% at one site to 90% and increased by 10% at another to a realized effectiveness of 82%. When factoring in the cost of ungulate collisions to society as a whole, fencing provided a net economic gain within 1 year of construction. Over a 10-year period, fencing would provide a net economic gain of >$500,000 per km in reduced collisions. In contrast, control site may take upwards of 90 years before the background rates of collisions decline to a break even point. Our study highlights the benefits of long-term monitoring of road mitigation projects and provides evidence of fencing effectiveness for reducing wildlife-vehicle collisions involving large mammals.
Role of Trusted Sources and Behavioral Beliefs in Promoting Mitigation Behaviors: Lessons from the COVID-19 Pandemic (Preprint)
(JMIR Publications Inc., 2022-02) Hanson, Bridget L.; Finley, Kari; Otto, Jay; Ward, Nicholas J.
Background: During the ongoing COVID-19 pandemic and in preparation for future public health crises, it is important to understand the relationship between individuals’ health beliefs, including their trust in various sources of health information, and their engagement in mitigation behaviors. Objective: We sought to identify relationships between trust in various sources of health information and the behavioral beliefs related to vaccination and mask wearing as well as to understand how behavioral beliefs related to vaccination differ by willingness to be vaccinated. Methods: We conducted an online survey of 1034 adults in the United States and assessed their trust in federal, local, and media sources of health information; their beliefs about vaccination; and their masking intention and vaccination willingness. Results: Using regression, masking intention was predicted by trust in the World Health Organization (P<.05) and participants’ state public health offices (P<.05), while vaccine willingness was predicted by trust in participants’ own health care providers (P<.05) and pharmaceutical companies (P<.001). Compared to individuals with low willingness to be vaccinated, individuals with high willingness indicated greater endorsement of beliefs that vaccines would support a return to normalcy, are safe, and are a social responsibility (P<.001 for all). Conclusions: Results can be used to inform ongoing public health messaging campaigns to manage the COVID-19 pandemic and increase readiness for the next pandemic. Additionally, results support the need to bolster the public’s trust in health care agencies as well as to enhance trust and respect in health care providers to increase people’s adoption of mitigation behaviors.
Implementing wildlife fences along highways at the appropriate spatial scale: A case study of reducing road mortality of Florida Key deer
(Pensoft Publishers, 2022-03) Huijser, Marcel P.; Begley, James S.
Florida Key deer mortality data (1966–2017) showed that about 75% of all reported deer mortalities were related to collisions with vehicles. In 2001–2002, the eastern section of US Hwy 1 on Big Pine Key (Florida, USA) was mitigated with a wildlife fence, 2 underpasses, and 4 deer guards. After mitigation, the number of reported Key deer road mortalities reduced substantially in the mitigated section, but this was negated by an increase in collisions along the unmitigated section of US Hwy 1 on Big Pine Key, both in absolute numbers and expressed as a percentage of the total deer population size. The data also showed that the increase in Key deer collisions along the unmitigated highway section on the island could not be explained through an increase in Key deer population size, or by a potential increase in traffic volume. The overall Key deer road mortality along US Hwy 1 was not reduced but was moved from the mitigated section to the nearby unmitigated section. Thus, there was no net benefit of the fence in reducing collisions. After mitigation, a significant hotspot of Key deer-vehicle collisions appeared at the western fence-end, and additional hotspots occurred further west along the unmitigated highway. Exploratory spatial analyses led us to reject the unmitigated highway section on Big Pine Key as a suitable control for a Before-After-Control-Impact (BACI) analysis into the effectiveness of the mitigation measures in reducing deer-vehicle collisions. Instead, we selected highway sections west and east of Big Pine Key as a control. The BACI analysis showed that the wildlife fence and associated mitigation measures were highly effective (95%) in reducing deer-vehicle collisions along the mitigated highway section. Nonetheless, in order to reduce the overall number of deer-vehicle collisions along US Hwy 1, the entire highway section on Big Pine Key would need to be mitigated. However, further mitigation is complicated because of the many buildings and access roads for businesses and residences. This case study illustrates that while fences and associated measures can be very effective in reducing collisions, wildlife fences that are too short may result in an increase in collisions in nearby unmitigated road sections, especially near fence-ends. Therefore it is important to carefully consider the appropriate spatial scale over which highway mitigation measures are implemented and evaluated.