On May 8, 2021, at the crack of dawn, patches of mist crept from the chilly fields onto Ziedeweg, a country road south of Amsterdam. The rush hour traffic caused by commuters using the road to avoid traffic jams on the highway had not yet been addressed. But another activity took place. Along the four-mile road, small groups of people carried bundles of white crosses and began to raise them quietly along the road. As the sun rose, the first motorists were greeted with an eerie spectacle: 642 crosses marked the precise spots where dozens of animals had been killed by vehicles in recent years. Each cross showed each animal’s common name, a drawing of the animal, and a QR code associated with the road accident recorded on the citizen science platform Observation International.
This guerrilla campaign was the brainchild of biologist Bram Koese, who was frustrated by the high numbers of otter and waterfowl deaths caused by speeding traffic and the lack of response from local authorities. Koese decided to take matters into his own hands and by mid-morning his parade of crosses was featured on the local and national news, rightly embarrassing the community.
Although not all share this intensity of activism, there are road death monitoring programs worldwide, such as Koese’s. Because road authorities themselves don’t routinely track the animals killed by traffic — and if they do, it’s only because such collisions pose a risk to human road users — most of the data comes from citizen scientists. These amateur researchers have found evidence that some species are threatened with extinction due to traffic.
An early effort in this direction was started in 1992 by Brewster Bartlett, also known as “Dr. Splatt,” then a physics teacher at Pinkerton Academy, a New Hampshire high school. He used the school’s first-ever email server to send observations. of students and posted on a bulletin board Since then, technology has improved and traffic accident monitoring is now done through dedicated apps or online citizen science platforms.
In Belgium, which has the densest road network in Europe, motorists can use speech recognition on the ObsMapp app to report and register traffic victims. In Israel, a roadkill mapping project relies on a feature in the Waze navigation app. Motorists can tap an icon representing the face of a porcupine envisioning a cross and sticking its tongue out when they see a dead animal.
In 2020, Clara Grilo of the University of Aveiro in Portugal and her colleagues collected data from 90 European road death studies and concluded that 194 million birds and 29 million mammals die on European roads every year. Similar calculations suggest that more than 350 million vertebrates are killed by traffic in the US each year
As astronomical as those numbers may be for larger animals, they pale in comparison to the amounts of insects and other smaller creatures that perish on the road. To get a grip on this, Arnold van Vliet of Wageningen University & Research in the Netherlands and his colleagues devised a citizen science project specifically aimed at insect mortality. Drivers were asked to take a daily photo of any insects that had been squashed onto their license plates, record their car’s mileage, and then scrub the license plate to start with a clean slate the next day. Extrapolating from the nearly 18,000 dead insects thus added up, the group estimated that, if expanded globally, it would mean 228 trillion insects are killed each year on the world’s 36 million kilometers of roads.
Community scientists don’t just map traffic accidents; they also map the roads themselves. They do so because that figure of 36 million kilometers is little more than a rough estimate – and it is quickly becoming obsolete. The world’s road network is expected to increase by 25 million kilometers by the middle of the century. The OpenStreetMap open licensing project aims to create a world map created by the general public for the general public. In 2016, a team of researchers used it to calculate that roads divide the country of the world into as many as 600,000 roadless lots. Half of it is smaller than a square kilometer and only 7 percent is more than 100 square kilometers. In other words, we live in a world completely shattered into tiny fragments encircled by the road.
And that, Grilo says, is bad news for the species of the world. She and her team combined information from the International Union for Conservation of Nature’s Red List of Threatened Species and existing data on road deaths and calculated the risk of road deaths for specific species. While some, such as the Eurasian blackbird (Turdus merula), suffering huge losses – as many as 35 million deaths a year – the population can absorb the losses without noticeable traffic-induced declines in numbers. Other species are not so lucky. the hazel grouse (Tetrastes bonasia) in Eurasia, the maned wolf (Chrysocyon brachyurus) in South America and the brown hyena (Hyaena brunnea) in southern Africa will likely be literally driven to extinction by road traffic in the coming decades.
So roadkill isn’t just the inevitable but minor collateral damage that inspires the raw humor of books like the faux field guide Flattened Fauna† The Roadkill USA Coloring and Activity Book or the lyrics to Loudon Wainwright III’s song “Dead Skunk,” “You got your dead skunk in the middle of the road stinkin’ to high heaven.” Vehicles are still overlooked by environmental forces that are likely to decimate more and more animal populations. While mitigation measures such as ‘ecoducts’, underpasses and fencing are helpful, they usually protect only one or a few species.
Perhaps more powerful are community awareness projects, such as Koese’s. The scientific data the researchers collected is just statistics, but hundreds of sanctuaries erected for the slain ermines, weasels, swallows, owls, frogs and geese produce a visual impact that sends the message to road users and builders that road deaths are no laughing matter. Unfortunately, some members of a local community through which the Ziedeweg passes were not impressed by the white crosses last year, says Koese with regret. “Two days after we put them down, they had knocked over all the crosses,” he says.