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10 million animals die on our roads each year. Here’s what works (and what doesn’t) to cut the toll

<p><em><a href="https://theconversation.com/profiles/graeme-coulson-1378778">Graeme Coulson</a>, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a> and <a href="https://theconversation.com/profiles/helena-bender-98800">Helena Bender</a>, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a></em></p> <p>There’s almost no warning. A dark shape appears on the side of the road, then you feel a jolt as something goes under the car. Or worse, the shape rears up, hits the front of your vehicle, then slams into the windscreen. You have just experienced a wildlife-vehicle collision.</p> <p>This gruesome scene plays out <a href="https://www.bbcearth.com/news/australias-road-kill-map">every night across Australia</a>. When these collisions happen, many animals become instant roadkill. An <a href="https://ses.library.usyd.edu.au/bitstream/handle/2123/23121/Thesis%20updated%20for%20library%20submission.pdf?sequence=1">estimated 10 million</a> native mammals, reptiles, birds and other species are killed each year.</p> <p>Others are injured and die away from the road. Some survive with <a href="https://theconversation.com/10-million-animals-are-hit-on-our-roads-each-year-heres-how-you-can-help-them-and-steer-clear-of-them-these-holidays-149733">terrible injuries and have to be euthanised</a>. The lucky ones might <a href="https://kb.rspca.org.au/knowledge-base/who-should-i-contact-about-injured-wildlife/">be rescued</a> by groups such as <a href="https://wildliferescue.net.au/">Wildlife Rescue</a>, <a href="https://www.wildlifevictoria.org.au/">Wildlife Victoria</a> and <a href="https://www.wires.org.au/">WIRES</a>.</p> <p>Wildlife-vehicle collisions also increase the risk to whole populations of some threatened species, such as <a href="https://doi.org/10.1071/WR17143">Lumholtz’s tree-kangaroo</a> on the Atherton Tablelands in Queensland.</p> <p>People are affected, too. Human <a href="https://doi.org/10.1111/1742-6723.13361">deaths and injuries</a> from these collisions are rising, with motorcyclists at greatest risk. Vehicle repairs are <a href="https://www.mynrma.com.au/-/media/wildlife-road-safety-report--final.pdf">inconvenient and costly</a>. Added to this is the distress for people when dealing with a dead or dying animal on the roadside.</p> <p>How can we reduce the wildlife toll on our roads? Many measures have been tried and proven largely ineffective. However, other evidence-based approaches can help avoid collisions.</p> <h2>Evidence for what works is limited</h2> <p>Many communities are worried about the growing impacts of wildlife-vehicle collisions and are desperate for solutions. Recent reports from <a href="https://www.diva-portal.org/smash/get/diva2:1822182/FULLTEXT01.pdf">Europe</a> and <a href="https://westerntransportationinstitute.org/wp-content/uploads/2021/12/4w7576_Huijser_etal_WVC_ConnectivityLiteratureReview_PooledFundStudyFinalReport_2021.pdf">North America</a> review the many methods to reduce such collisions.</p> <p>Do these findings apply to Australia’s unique fauna? Unfortunately, we don’t have a detailed analysis of options for our wildlife, but here’s what we know now.</p> <p>Well-designed fences keep wildlife off our highways but also fragment the landscape. Happily, animals will use crossing structures – overpasses and <a href="https://theconversation.com/good-news-highway-underpasses-for-wildlife-actually-work-187434">underpasses</a> – to get to food and mates on the other side of the road. Fences and crossings do work, but are regarded as too costly over Australia’s vast road network.</p> <p>As for standard wildlife warning signs, drivers <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4494358/">ignore most of them</a> after a while, making them ineffective. Signs with graphic images and variable messages get <a href="https://doi.org/10.3390/ani3041142">more attention</a>, but we need road trials to assess their effect on drivers and collision rates.</p> <h2>Whistling in the dark</h2> <p>Some drivers install cheap, wind-driven, high-pitched wildlife whistles on their vehicles. Tests in the United States 20 years ago found humans and deer <a href="https://doi.org/10.1121/1.1582071">could not hear any whistling sound</a> above the road noise of the test vehicle. Yet these devices are still sold in Australia as kangaroo deterrents.</p> <p>The Shu-Roo, an Australian invention, is an active wildlife whistle. It is fitted to the bumper bar, producing a high-pitched electronic sound, which is claimed to scare wildlife away from the road. Sadly, <a href="https://rest.neptune-prod.its.unimelb.edu.au/server/api/core/bitstreams/3c3154e0-2f48-5b73-a6cd-a7423c2a75ee/content">our tests</a> show the Shu-Roo signal can’t be heard above road noise 50 metres away and has no effect on captive kangaroo behaviour.</p> <p>We also recruited fleets of trucks, buses, vans, utes and cars to field test the Shu-Roo. Nearly 100 vehicles covered more than 4 million kilometres across Australia over 15,500 days. The drivers reported just over one wildlife-vehicle collision per 100,000km travelled, but <a href="https://doi.org/10.7882/AZ.2021.042">there was no difference in the rate</a> for vehicles fitted with a Shu-Roo versus those without one.</p> <p>The virtual fence is the latest attempt to reduce wildlife-vehicle collisions. It uses a line of posts spaced along the roadside, each with a unit producing loud sounds and flashing lights aimed away from the road. Vehicle headlights activate the units, which are claimed to alert animals and reduce the risk of collision.</p> <p>Early results from Tasmania were encouraging. A 50% drop in possum and wallaby deaths was reported, but <a href="https://doi.org/10.1071/AM19009">this trial had many design flaws</a>. Recent trials in <a href="https://www.mdpi.com/2076-2615/9/10/752">Tasmania</a>, <a href="https://www.mdpi.com/2076-2615/12/10/1323">New South Wales</a> and <a href="https://www.redland.qld.gov.au/downloads/download/292/virtual_fence_to_reduce_vehicle_collisions_with_wallabies_on_heinemann_rd_-_final_report_2020">Queensland</a> show no effect of virtual fencing on collisions with possums, wallabies or wombats.</p> <p>Our concern is that this system is being <a href="https://www.abc.net.au/news/2020-06-02/wildlife-fence-trial-underway-in-queensland-and-phillip-island/12268110">rolled out</a> in <a href="https://www.townsville.qld.gov.au/about-council/news-and-publications/media-releases/2023/june/councils-innovative-trial-helping-keep-local-wildlife-safe">many</a> <a href="https://www.abc.net.au/news/2022-10-26/nsw-south-coast-council-first-virtual-fence-to-protect-wildlife/101571600">parts</a> of <a href="https://www.theage.com.au/politics/victoria/the-stealth-tech-aiming-to-stop-roos-from-becoming-roadkill-20231222-p5etda.html">Australia</a>. It gives the impression of action to reduce collisions with wildlife, but without an evidence base, solid study design or adequate monitoring.</p> <h2>A very messy problem</h2> <p>The problem has many dimensions. We need to consider all of them to achieve safe travel for people and animals on our roads.</p> <p>At a landscape level, collision hotspots occur where wildlife frequently cross roads, which can help us predict the collision risk for species such as <a href="https://doi.org/10.1111/aec.13465">koalas</a>. But the risk differs between species. For example, <a href="https://doi.org/10.1016/j.gecco.2021.e01530">on Phillip Island</a> most wallaby collisions happen on rural roads, while most involving possums and birds are in urban streets.</p> <p>Traffic volume and speed are key factors for many species, including <a href="https://doi.org/10.1002/ece3.2306">kangaroos</a>.</p> <p>Driver training and experience are also important. In the Royal National Park in New South Wales, <a href="https://www.mdpi.com/2076-2615/6/6/40">half the drivers surveyed</a> had struck animals, including wallabies and deer. Yet most still <a href="https://theconversation.com/10-million-animals-are-hit-on-our-roads-each-year-heres-how-you-can-help-them-and-steer-clear-of-them-these-holidays-149733">weren’t keen</a> to slow down or avoid driving at dawn and dusk.</p> <p>Road design has a major influence on wildlife-vehicle collions too, but the planning process too often <a href="https://www.frontiersin.org/articles/10.3389/fenvs.2022.959918">neglects wildlife studies</a>.</p> <p>Smarter cars are <a href="https://www.diva-portal.org/smash/get/diva2:1822182/FULLTEXT01.pdf">being developed</a>. One day these will use AI to spot animal hazards, apply automatic emergency braking and alert other drivers of real-time risk.</p> <p>To explore potential technological solutions, Transport for NSW is running a <a href="https://www.eianz.org/events/event/symposium-using-technology-to-reduce-wildlife-vehicle-collisions">symposium</a> at the University of Technology Sydney on May 21. The symposium will cover wildlife ecology and the evidence base for options to reduce wildlife-vehicle collisions in Australia.</p> <hr /> <p><em>If you see an injured animal on the road, call <a href="https://www.wildliferescue.net.au/">Wildlife Rescue Australia</a> on 1300 596 457. for specific state and territory numbers, go to the <a href="https://kb.rspca.org.au/knowledge-base/who-should-i-contact-about-injured-wildlife/">RSPCA injured wildlife site</a>.</em><!-- Below is The Conversation's page counter tag. 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More info: https://theconversation.com/republishing-guidelines --></p> <p><a href="https://theconversation.com/profiles/graeme-coulson-1378778"><em>Graeme Coulson</em></a><em>, Honorary Principal Fellow, School of BioSciences, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a> and <a href="https://theconversation.com/profiles/helena-bender-98800">Helena Bender</a>, Senior Lecturer, Environmental Social Sciences, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a></em></p> <p><em>Image credits: Getty Images </em></p> <p><em>This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/10-million-animals-die-on-our-roads-each-year-heres-what-works-and-what-doesnt-to-cut-the-toll-222367">original article</a>.</em></p>

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