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Consensus is lacking regarding the influence of vehicle speed and traffic volume on deer–vehicle collision (DVC) rates. Yet, annual average daily traffic fl ow (AADT) and posted speed limit (PSL) typically are used to measure these variables. To resolve this confl ict, we studied the effects of traffic volume and vehicle speed on DVCs in Utah. Our results showed no relationship between AADT or PSL and DVC occurrence. There are at least 3 explanations for our results: (1) no causal relationship exists; (2) AADT and PSL, as measured, actually explain little of the variation; and (3) data quality problems exist. We discuss the likelihood for each explanation. We argue that even though traffic speed and volume have been used to predict DVC occurrence and may be useful explanatory variables, the metrics AADT and PSL are poor surrogate variables. Thus, uses of these variables to predict risk will likely provide unreliable results.

Globally, human activities impact from one-third to one-half of the earth’s land surface; a major component of development involves the construction of roads. In the US and Europe, road networks fragment normal animal movement patterns, reduce landscape permeability, and increase wildlife-vehicle collisions, often with serious wildlife population and human health consequences. Critically, the placement of wildlife crossing structures to restore landscape connectivity and reduce the number of wildlife-vehicle collisions has been a hit-or-miss proposition with little ecological underpinning, however recent important developments in allometric scaling laws can be used to guide their placement. In this paper, we used cluster analysis to develop domains of scale for mammalian species groups having similar vagility and developed metrics that reflect realistic species movement dynamics. We identified six home range area domains; three quarters of 102 species clustered in the three smallest domains. We used HR0.5 to represent a daily movement metric; when individual species movements were plotted against road mile markers, 71.2% of 72 species found in North America were included at distances of less-than-or-equals, slant1 mi. The placement of wildlife crossings based on the HR0.5 metric, along with appropriate auxiliary mitigation, will re-establish landscape permeability by facilitating wildlife movement across the roaded landscape and significantly improve road safety by reducing wildlife vehicle collisions.

Collisions between large vertebrates and vehicles along roadways are an increasing concern, not only because of ecological consequences, but also because of associated economic and social costs. We used a large-scale, long-term data set comprising several databases from Utah to summarize and analyze these costs. The overall cost for 13,020 collisions from 1996 to 2001 in Utah was approximately $45,175,454, resulting in an estimated average per year cost of about $7,529,242 and a mean collision cost of $3,470. These figures include human fatality costs of $24 million (53% of total costs); vehicle damage costs of $18 million (39%); loss of deer, valued at $2.7 million (6%); and human injury costs of $1 million (2%). Cost-benefit analyses have shown that mitigation efforts, which are prioritized based on road-kill data, can produce positive net economic gains and also increase driver safety.

We examined spatial patterns of carnivore casualties by counting the number of animals killed on 574 km of national roads and highways in southern Portugal. We surveyed six national roads twice a month from July 2003 to December 2006. Highway casualty data were collected by Brisa Auto-Estradas de Portugal, S. A., a private concession. A total of 801 carnivores representing eight carnivore species were killed. We found an average of 47 vehicle-killed individuals/100km/year; foxes were most numerous with the 20 individuals killed/100km/year. The distribution of carnivore vehicle-kills was clustered except fox. We calculate the mean road kill rate on different classes of variables that may influence road mortality and compare among them to identify the level of risk posed by each class of variable. Casualties were more likely to occur near to suitable habitats preferred by carnivores, in high traffic volume areas, and close to streams. Livestock exclusion fences, the type of road, and the number of passages did not influence mortality. To improve the cost-effectiveness of mitigation measures for new and existing roads, the priority should be given to the road segments crossed by streams in a cork oak woodlands matrix. Short sections of buried fences near culvert openings (100m on each side) should reduce the number of casualties considerably. Habitats connectivity is a serious issue where high volume traffic discourages carnivores from crossing roads at-grade. Connectivity is enabled by appropriately-designed passages.

Several indirect effects of roads on wildlife communities have been reported such as habitat quality alteration, loss in landscape connectivity, and barrier effects (Forman et al., 2003; Jaeger et al., 2005). An effect zone of up to 100m on either side of the road has been described as causing measurable impacts on ecological communities (Underhill and Anglod, 2000).Roads can impact small mammal communities by: 1) creating an edge with different habitat characteristics (Garland and Bradley, 1984; Tyser and Worley, 1992); 2) promoting the introduction of exotic species (Getz et al., 1978; Vermeulen and Opdam, 1995; Underhill and Anglod, 2000); 3) increasing stress and reducing survival (Benedict and Billeter, 2004) through disturbance and contamination (Jefferies and French, 1972; Williamson and Evans, 1972; Quarles et al., 1974); 4) blocking movement thus causing genetic barriers and home range rearrangements (Oxley et al., 1974; Garland and Bradley, 1984; Mader, 1984; Swihart and Slade, 1984; Merriam et al., 1989; Gerlach and Musolf, 2000); and finally 5) causing direct road mortality (Wilkins and Schmidly, 1980; Ashley and Robinson, 1996; Mallick et al., 1998).While the main focus of studies on the impact of roads on small mammals has been on road barrier effects, less attention has been given to the effect of roads on density and diversity of local communities.Further analysis on the effect of roads on natural habitats is needed. Our objective was to assess and compare density estimators and diversity of small mammal communities in areas influenced by roads with areas having no road influence.

Results are presented of a North American survey designed to learn how transportation departments mitigate transportation corridors for wildlife and give examples of how wildlife mitigation measures can be incorpo¬rated into long range plans and in routine everyday actions. The objective is to promote greater understanding of the potential for incorporating wildlife movement needs into transportation programs and projects. Research results presented include data from a continent-wide telephone survey conducted over a two year period (2004-2006) to learn of accomplishments in wildlife passage and how wildlife and ecosystem needs have been incorporated into the trans¬portation planning process. Telephone interviews were conducted with 410 transportation and ecology professionals in every state and province. Based on research data and the mandates of the SAFETEA-LU legislation the case is made that greater efforts in long term transportation plans and everyday retrofits are necessary to provide for wildlife and ecosystems needs. Some efforts have already been accomplished and can be adapted continent-wide. There are greater than 580 terrestrial and 10,000 aquatic wildlife and fish passages in North America that were specifically built as wildlife and fish crossings, and millions of other bridges and culverts constructed for other purposes but which could be used by wildlife. Placement of these structures has grown so rapidly that over 500 new terrestrial passages are projected to be built in the next 10 years. The almost exponential increase in passage construction each decade is an indication of the growing awareness of the need to mitigate new and existing transportation infrastructure for wildlife permeability. There is also a greater awareness that early planning for wildlife and ecosystems is critical to accomplish these mitigation activities. The inclusion of wildlife and ecosystem needs early in the development of long range transportation plans has not been the traditional paradigm as was learned over the course of the survey. The majority of transportation planners who participated in the survey indicated their state’s consideration of wildlife and ecosystems, in the form of consultations with natural resource professionals and referencing Geographic Information Systems (GIS) maps and other data, did not occur until the project development stage. This late consideration does not typically allow adequate time to avoid important wildlife corridors and to install mitigation measures. The majority of those working with transportation and ecological concerns recognized the need to incorporate wildlife mitigation needs early in the programming, planning, and design processes, as learned from the web-based priorities survey. The survey revealed that early planning for wildlife and ecosystem needs was the number one priority in dealing with roads and wildlife. This early level planning has also been mandated in the U. S. SAFETEA-LU Transportation Act of 2005. Examples are presented of instances where long range planning included wildlife and ecosystems needs, and suggest how this can be accomplished on a state and province-wide basis. We also present how everyday opportunities can be used to facilitate wildlife movement over and under roads and railways. Knowledge of successful accomplishments can help build upon opportunities in the movement toward a more proactive transportation planning paradigm.

Our primary purpose was to develop, to the extent that data are available, and as part of a web-based wildlife and roads resource, clearly written decision guidelines for: 1) the selection, configuration, and location of crossing types; 2) the monitoring and evaluation of crossing effectiveness; and 3) for maintenance.Until recently, concerted and purposeful activity towards linking transportation and ecological services into a context-sensitive planning, construction, and monitoring process has not been attempted. We began a 3 year project in June 2004 funded by the National Cooperative Highway Research Program (National Academy of Sciences and Engineering, Transportation Research Board) and titled NCHRP Project 25-27, Evaluation of the Use and Effectiveness of Wildlife Crossings. We consider landscape permeability the foundation for effective wildlife-road mitigation and the guiding principle for this work. Our primary purpose was to develop, to the extent that data are available, and as part of a web-based wildlife and roads resource, clearly written decision guidelines for: 1) the selection, configuration, and location of crossing types; 2) the monitoring and evaluation of crossing effectiveness; and 3) for maintenance. The decision guidelines are based on the premise that understanding and establishing landscape permeability leads to effective landscape connectivity and the restoration of ecosystem integrity. At the same time, the guidelines must allow for efficient and cost-effective transportation infrastructure mitigation. In the decision guidelines, we describe seven steps that can be used to assist in effective wildlife mitigation, including: 1) consideration of the ecological and safety needs for mitigation early in the planning process, 2) decisions regarding the types of structures needed based on species-specific requirements, 3) the placement of those structures, and 4) their configuration on the landscape, 5) information on monitoring and evaluating crossing effectiveness, and 6) the long term maintenance of those structures. The final step (7) is the compilation of end products that are summarized in a final plan for mitigation with references, diagrams, pictures, and website addresses for the user to take from the website and use for additional consultation. The decision guidelines will be based on available data. It is clear that continued research efforts will be needed to fully develop aspects of the decision tool. The guidelines can be accessed at the URL www.wildlifeandroads.org. They are based on relevant research and effective mitigation practices from around the world, including 7 studies we conducted expressly for this project. The website includes descriptions of several methodologies that can be used to identify wildlife-vehicle collision hotspots, as well as suggestions for effective mitigation measures. The site also provides the ability to search databases for pertinent information. For example, the site includes an interactive map of wildlife passages across North America where, for example, the user can search by state and species and return a listing of pertinent refer¬ences, a list of available pdf reports and papers accessible from the site, a listing of the wildlife crossings in that state, a listing of pertinent URL addresses that have wildlife-road related data, and a list of images with descriptions that can be freely downloaded. Alternatively, the user can search the entire database for a specific type of crossing and return all data across North America about that subject. The web site and decision guidelines will be continually developed and become a resource that provide practical information to help practitioners develop appropriate mitigation that will provide for effective landscape permeability for wildlife and safer roads for people.

In this paper we present results from a telephone survey as part of a National Cooperative Highway Research Program (NCHRP) project, Evaluation of the Use and Effectiveness of Wildlife Crossings (NCHRP 25-27). Specifically, we present a summary of North American efforts to mitigate road effects for wildlife. We stress the need to provide multiple wildlife passages along transportation corridors to begin to accommodate the movement of the full complement of species in an area. We surveyed over 250 transportation professionals in the United States and Canada by telephone to learn more about efforts to make roads more permeable for wildlife. We asked questions about both the practice and science associated with road ecology. Participants employed by agencies, private organizations, and academic institutions answered questions concerning wildlife crossings, planning for wildlife and ecosystems, animal-vehicle collision information, and past, current, and future research activities related to roads and wildlife. As of September 2005, we found that there were at least 460 terrestrial and 300 aquatic crossings in North America. Trends in practice over time since wildlife passages began to be installed in the 1970s appear to show an increased number of target species in mitigation projects, increased numbers of endangered species used as target species for mitigation, increasing involvement of municipal and state agencies, an increase in the number of passages and accompanying structures constructed, and a continent-wide trend of neglect of maintenance of these passages. The trends in the science revealed a tendency for a broadening of the scope of research in terms of the number of species considered, an increase in the length of time monitoring projects were conducted, and an increase in the number of participants in scientific monitoring of mitigation projects and in general road ecology research. There are several projects in North America where multiple crossings have been or will be installed to accommodate a large suite of species and their movement needs. These include Alberta’s Trans Canada Highway mitigation efforts, Montana’s U.S. Highway 93 mitigation projects, Arizona’s projects along U.S. 93 and on State Route 260, Florida’s I-75 Alligator Alley project, and Vermont’s future Route 78 and US 7-SR 9 projects. These projects may be models for how road construction activities can increase the permeability of the roaded landscape. We also present recommendations to assist in the research, design, placement, monitoring, and maintenance of crossings. We summarize the state of the practice and science of road ecology with respect to wildlife with suggestions to increase permeability of transportation corridors, and to increase communication and cooperation among those who would be involved in the mitigation of roads and other travel corridors

in a 20-mile stretch of Interstate15 south of its confluence with Interstate 70 led to the establishment of a mitigation strategy focused on mule deer. The strategy focused on two major objectives: 1) decrease wildlife-vehicle crashes and 2) maintain and improve landscape permeability that facilitates wildlife movement across the highway. The mitigation put in place involved the construction of exclusion fencing, right-of-way escape ramps, and two underpasses designed primarily for large-mammal passage. In this study, we assessed the effectiveness of the mitigation measures in reducing mule deer mortality and evaluated the success of the new underpasses in allowing wildlife to cross the road safely. In this poster, we compare the pre- and post-construction levels of road mortality. We also report observed problems with the mitigation structures as well as the solutions we used to solve them. We used remotely sensed cameras to record deer passage through the new underpasses during the Fall 2004 and Spring 2005 migrations and compare results with a 20-year old ‘control’ structure. Early results showed a sporadic and lower use of the new underpasses. We suspect that the novel presence of the new crossing structures, coupled with historic learned-behavioral migration patterns, may be responsible for these early results. The number of animals that used the new structures, however, leaves optimistic expectations for increased use in the future. We will test the prediction of increased use during the Fall 2005 and Spring 2006 migrations. In this poster, we also address the use of bait to encourage passage, and report on the occurrence of startle behavior in response to heavy traffic, suggesting that it may be fruitful to explore the effects of noise and the visual barriers to encourage underpass passage by wildlife.

Wildland road removal is a common practice across the U.S. and in some parts of Canada. The main types of road removal include ripping, stream crossing restoration, and full recontour. Road removal creates a short-term disturbance that may temporarily increase sediment loss. However, research and long-term monitoring have shown that road removal both reduces erosion rates and the risk of road-induced landslides. Research is needed to determine whether road removal is effective at restoring ecosystem processes and wildlife habitat. We propose several research questions and the types of studies needed to further road removal efforts. With greater understanding of the impacts of road removal, land managers can more effectively prioritize which roads to leave open and which roads to consider for future road removal projects.

It is clear that a reduction in both direct and indirect effects of roads and road networks must be the goal of management agencies. However, increased permeability of roaded landscapes can only be achieved by up-front planning and subsequent mitigative actions. The key is to understand that roads must be made permeable to the movement of animals. More profoundly, ecosystem services, i.e., clean water, clean air, uncontaminated soil, natural landscapes, recreation opportunities, abundant wildlife, and life sustaining ecological processes must not be seriously impacted. In other words, quality of life as measured by ecosystem services should be a major component of the planning process when roads are constructed or improved.Mitigative structures exist to increase permeability of roads. Wildlife overpasses and underpasses, often referred to as ecoducts or green bridges, with associated structures to enable larger animals to exit the road right of way, e.g., earthen escape ramps (Bissonette and Hammer, 2001), various culvert designs for smaller animals including badger pipes and amphibian and reptile runnels, and fish ladders are but a small sampling of the structures already in place around the world. What is needed is attention to the big picture. Landscapes need to be reconnected and made more permeable. Responsible agencies and organizations need to be aggressive about promoting mitigations and a conservation ethic into road planning. Only with a broad based effort between a concerned public, a database to work from, and a willingness of responsible agencies, will the now very large virtual footprint of roads and road networks be reduced to more closely approximate the physical footprint. By embracing the Cinderella Principle of making the virtual shoe fit more closely the actual physical footprint of roads, we will be able to achieve a closer connection with ecological harmony with its resultant effect of abundant wildlife.

Conventional wisdom and highway practice across many states seemed to suggest that high (~2.4 m) ‘deer-proof’ fencing, coupled with underpasses are the mitigation of choice to prevent deer (and other ungulate) mortalities on U.S. highways. Our observations here in Utah and those elsewhere in the U.S. strongly suggested that few, if any, so called ‘deer-proof’ fences totally eliminated deer from accessing the Right-of Way (ROW) on fenced roads. In Sardine Canyon (US 91) in northern Utah, more than 50 deer were killed in one year on the road in a short section (MP 6.0- MP10) after the road was widened and fenced. This suggested to us that highway mitigation aimed at reducing deer-vehicle collisions needed to take into consideration measures that allowed deer to readily exit the highway ROW. We conducted a two-year study (October 1997- November 1999) to examine the effectiveness of earthen escape ramps in allowing deer to escape the highway ROW. We compared their performance with one-way steel escape gatesWe identified two study sites in Utah with a history of high deer road kill and deer fencing, US 91 (MP 6 – MP 10) and US 40 (MP 4 – MP 13) as appropriate for study. During the period of the study (October 1997 – November 1999) we conducted regular spotlight counts to assess deer population trends at both sites. Concurrently, we recorded deer kills on both sites throughout the period. Earthen escape ramps were installed on US 91 in October 1997 (n = 9) and on US 40 between July and August 1998 (N = 7). We established track plots on each ramp in order to assess use by deer. Similarly, track plots were established at 10 one-way gates on US 91 and at 8 gates on US 40. At both sites, gates in the vicinity of the ramps were used. Ramps at the US 91 site were checked 61 times during the study and 188 successful crossings recorded. At the US 40 site, ramps were checked 42 times and 192 successful crossings recorded. Gates were checked 52 and 40 times during the study at the US 91 and US 40 sites, respectively. Fifteen of 45 (33.3%) deer at US 91 and 31 of 63 (49.2%) deer at US 40 passed through the gates successfully.We compared the effectiveness of earthen escape ramps with one-way gates by standardizing their use into ‘ramp’ and ‘gate’ days. We then developed an index of use. At both sites, ramps were much more effective than gates in allowing deer to escape the ROW. Combined values from both sites suggest that earthen escape ramps were from approximately 8 to 11 times more effective than one-way gates. Our cost benefit analysis, using a deer valuation based on actual expenditures for deer hunting and adjusted for compensatory mortality, suggested that the cost of installing earthen escape ramps is rapidly offset by reduction in deer mortality. We recommend that earthen escape ramps be incorporated into mitigation when deer fencing is being considered for installation on Utah roads.