@futurebird Sadly, the follow-up:
Anne Ollila, director of the Finnish Reindeer Herders' Association, said Wednesday the other methods simply didn't work.
"Drivers often mistook reindeer with reflectors for people in the dark, thinking they wouldn't run into the middle of the road when they saw car headlights approaching," she told The Associated Press. "And the deer would tear the reflectors off."
In this picture taken July 13, 2009, reindeers walk across the road in Suomussalmi, Finland. Finnish reindeer herders launch app to cut road kills in northern Arctic where 300,000 reindeer regularly roam freely. ( Vesa Moilanen/ Lehtikuva via AP)Reindeer traffic warning signs were pinched by tourists for souvenirs, and reindeer would scrape off the fluorescent paint from their antlers. "Somehow the reindeer know they had paint on their antlersβmaybe their friends laughed at them," Ollila said.
(Source: https://phys.org/news/2016-06-reindeer-herders-finland-app-road.html.)