Elevated wildlife-vehicle collision rates during the COVID-19 pandemic

Lifetime cost analysis of concrete barriers and steel guardrails

This study investigates the lifetime costs associated with concrete barriers and steel guardrails. We introduce a cost analysis methodology that incorporates critical factors such as construction costs, maintenance costs, exposure risks during maintenance activities, and the costs imposed to traveling public through the increased traffic and the crash outcomes. We integrate various parameters including economic factors, road geometry, general weather condition, and traffic mix to estimate a location-dependent cost for each type of barrier accurately. A software tool, named CalBarrier, was developed during this study to carry out the calculations and the comparison of lifetime cost of aforementioned barriers. An inherent strength of this research is its reliance on recent real data extracted from various databases of California Department of Transportation (Caltrans), ensuring precision and relevance in accounting for various influential factors. Drawing insights from Caltrans practices and interviews with their personnel, this study emphasizes the intricate decision-making process involved in mitigating safety risks and reducing operational expenses. Although our data originates from California, the methodology for life cycle cost analysis, and our software are applicable for regions with different socio-economic conditions by deploying user input costs, making our findings a valuable resource for other areas facing comparable challenges.

Mammal Roadkills in Lithuanian Urban Areas: A 15-Year Study

We investigated roadkills in urban areas in Lithuania from 2007 to 2022, including two periods with COVID-19 restrictions on people's movement. We analyzed the proportions of wild and domestic animals in roadkill, annual trends, the predominant species involved, and monthly changes during the restrictions. Urban roads were characterized by a low species diversity of roadkilled mammals, with roe deer (Capreolus capreolus) dominating. Total numbers increased exponentially during the study period. The proportion of domestic animals, 12.2%, significantly exceeded that on non-urban roads in the country. The proportion of domestic animals decreased from over 40% in 2007-2009 to 3.7-5.4% in 2020-2022, while the proportion of wild mammals increased from 36.1-39.6% to 89.9-90.6%, respectively. During the periods of COVID-19 restrictions, the number of roadkills in urban areas was significantly higher than expected based on long-term trends. Compared to 2019, the number of roadkilled roe deer in 2020-2021 almost doubled from 700 to 1281-1325 individuals. These anthropause effects were, however, temporary. The imbalance between the roadkill number and transport intensity might require new mitigation strategies to sustain mammal populations in urban areas, at least through improving driver awareness on the issue.

Lockdown's Silver Lining? Different Levels of Roadkill during the COVID-19 Times in Lithuania

The impact of COVID-19 restrictions on human and vehicular mobility on the number of roadkills of wild mammals, and roe deer in particular, was assessed in Lithuania. We statistically analyzed the distribution of all mammals and roe deer (Capreolus capreolus) as the most abundant species annually from 2002 to 2022 and monthly from 2020 to 2021, including during the two restriction periods. Notably, there was a marked decrease in roadkill incidents on main, national and regional roads, particularly in April-May 2020 (the beginning of lockdown period I) and November-December 2020 (the beginning of lockdown period II), 5.1-20.8% and 33.6-54.4%, respectively. During these months, collisions with mammals on the A14 main road were reduced by 75-90%. However, there was a significant increase in the number of roadkills in urban areas, resulting in the total number of mammal-vehicle and roe deer-vehicle collisions in 2020 and 2021 being higher than expected based on long-term trends. However, after restrictions were eased, collision numbers with wildlife on the main, national and regional roads increased again and became higher than expected.

The impact of the COVID-19 pandemic on wildlife-aircraft collisions at US airports

Exploiting unprecedented reductions in aircraft movements caused by the COVID-19 pandemic, we investigated the relationship between air traffic volume and the frequency of wildlife-aircraft collisions, or wildlife strikes, at the 50 largest airports in the United States. During the COVID-19 months of 2020 (March-December), both air traffic volume and the absolute number of wildlife strikes were reduced. The net effect of these two movements, however, was an increase in the wildlife strike rate from May 2020-September 2020. This increase was found to be most pronounced at airports with larger relative declines in air traffic volume. We concluded that the observed increase in the wildlife strike rate was, at least in part, generated by risk-enhancing changes in wildlife abundance and behavior within the airport environment. That is, wildlife became more abundant and active at airports in response to declines in air traffic volume.

A before-after-control-impact study of wildlife fencing along a highway in the Canadian Rocky Mountains

Wildlife exclusion fencing has become a standard component of highway mitigation systems designed 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 changes the rate of collisions. We used a replicated (n = 2 sites monitored for over 1000 km years combined) 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 the combination of fence intrusions and low sample sizes. We calculated realized fencing effectiveness by applying the same change in collision rates observed at control (unfenced) sites as the expected change for adjacent fenced sections. Compared with the apparent fencing effectiveness (i.e., the difference in WVCs rates before and after fencing was installed), the realized estimates of fencing effectiveness declined by 6% at one site and increased by 10% at another site. When factoring in the cost of ungulate collisions to society, 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. 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.

Characteristics of kangaroo-related motor vehicle crashes

BACKGROUND

Kangaroo-related motor vehicle collisions are common but there is limited literature on this topic. Drivers confronted by kangaroos may choose to swerve or to directly collide with the kangaroo. The effect of these differing crash mechanisms, along with the effect of vehicle type or time of day, has not yet been reported.

METHODS

A retrospective cohort study was performed, examining patients admitted to our tertiary trauma centre for kangaroo-related motor vehicle collisions between 2000 and 2020. Data on patient demographics, crash characteristics, and hospital stay were collected and analysed.

RESULTS

A total of 366 patients were included and were predominantly male (76%) with an median age of 40. Swerve crashes were more common (59%) than direct impact and swerving was a statistically significant predictor of reduced injury severity score on multivariable analysis (other significant factors were female sex and no rollover). Motor vehicle crashes and motorbike crashes had differing crash characteristics. Motor vehicle crashes were more likely the result of swerving, and swerving was less likely to cause ejection or require extrication but more likely to cause rollover. Motorbike crashes however, were more likely the result of head on collision and riders were more likely to be ejected from the vehicle, require extrication, or be involved in a rollover. In terms of time of day, there were more crashes at dawn and there was a trend towards higher injury severity score and length of stay for night-time crashes.

CONCLUSION

For kangaroo-related motor vehicle crashes, predictors of increased injury severity score on multivariable analysis were male sex, direct impact, and rollover. Motorbikes and motor vehicles had differing crash mechanisms and characteristics, as did night-time crashes when compared to daytime or twilight crashes.

LEVEL OF EVIDENCE

IV, prognostic.

Wombat Roadkill Was Not Reduced by a Virtual Fence. Comment on Stannard et al. Can Virtual Fences Reduce Wombat Road Mortalities? Ecol. Eng. 2021, 172, 106414

The roadkill of wildlife is a global problem. Much has been written about deterring wildlife from roads, but, as of yet, there is no empirical support for deterrents based on visual and/or auditory signals. A recent paper entitled 'Can virtual fences reduce wombat road mortalities?'reported the results of a roadkill mitigation trial. The authors installed a 'virtual fence' system produced by iPTE Traffic Solutions Ltd. (Graz, Austria) and evaluated its effectiveness for reducing roadkills of bare-nosed wombats (Vombatus ursinus) in southern Australia. The authors recorded roadkills in a simple Before-After-Control-Impact design but did not conduct any formal statistical analysis. They also measured three contextual variables (vegetation, wombat burrows, and vehicle velocity) but did not link these to the occurrence of roadkills in space and time. The authors concluded that the iPTE virtual fence system was 'minimally effective', yet 'appears promising'. Our analysis of their data, using standard inferential statistics, showed no effect of the virtual fence on roadkills whatsoever. We conclude that the iPTE system was not effective for mitigating the roadkills of bare-nosed wombats.

Animal-vehicle collisions during the COVID-19 lockdown in early 2020 in the Krakow metropolitan region, Poland

The interrelations between human activity and animal populations are of increasing interest due to the emergence of the novel COVID-19 and the consequent pandemic across the world. Anthropogenic impacts of the pandemic on animals in urban-suburban environments are largely unknown. In this study, the temporal and spatial patterns of urban animal response to the COVID-19 lockdown were assessed using animal-vehicle collisions (AVC) data. We collected AVC data over two 6-month periods in 2019 and 2020 (January to June) from the largest metropolis in southern Poland, which included lockdown months. Furthermore, we used traffic data to understand the impact of lockdown on AVC in the urban area. Our analysis of 1063 AVC incidents revealed that COVID-19 related lockdown decreased AVC rates in suburban areas. However, in the urban area, even though traffic volume had significantly reduced, AVC did not decrease significantly, suggesting that lockdown did not influence the collision rates in the urban area. Our results suggest that there is a need to focus on understanding the effects of changes in traffic volume on both human behaviour and wildlife space use on the resulting impacts on AVC in the urban area.

Impact of COVID-19 Lockdown on Wildlife-Vehicle Collisions in NW of Spain

Wildlife–vehicle collisions (WVCs) in many places have a significant impact on wildlife management and road safety. The COVID-19 lockdown enabled the study of the specific impact that traffic has on these events. WVC variation in the Asturias and Cantabria regions (NW of Spain) because of the COVID-19 lockdown reached a maximum reduction of −64.77% during strict confinement but it was minimal or nonexistent during “soft” confinement. The global average value was −30.22% compared with the WVCs registered in the same period in 2019, but only −4.69% considering the average throughout the period 2010–2019. There are huge differences between conventional roads, where the traffic reduction was greater, and highways, where the traffic reduction was lesser during the COVID-19 lockdown. The results depend on the season, the day of the week and the time of day, but mainly on the traffic reduction occurring. The results obtained highlight the need to include the traffic factor in WVC reduction strategies.

Anthropause Opportunities: Experimental Perturbation of Road Traffic and the Potential Effects on Wildlife

The SARS-CoV-2 pandemic severely reduced many human activities. So pronounced was the change, it has given rise to the term “anthropause”: the considerable alteration of modern human activities. Among these was surface transportation, with prolonged traffic reductions, in excess, of 50% in many countries. Roads and traffic are responsible for functionally fragmenting ecosystems, wildlife populations, and species interactions. The unintentional “dialing-down” of traffic has given continuous monitoring systems of wildlife-vehicle conflict a unique opportunity to study the consequences of perturbing this source of wildlife disturbance and mortality. Experimental manipulation of traffic at the global scale would not have been possible without mitigation responses to SARS-CoV-2. Such a perturbation allows robust empirical investigation into wildlife responses to traffic, including changes in mortality, behavior, genetic connectivity, and knock-on ecosystem effects, the responses to which can be replicated across a global network of wildlife-vehicle conflict monitoring systems. We review the extent to which these extensive data-collection systems provide the primary source of data to study many of these responses, providing the raw material to understand some striking wildlife consequences of the anthropause.