The reflectors, which are made of corn to avoid them littering the environment, have been shown to successful in trials run since 2010 and are now being rolled out across the country's herds.
"Reindeer are pack animals so we don’t need to mark all of them, "Kristian Øvernes, a senior adviser at the Norwegian Public Roads Administration, told NRK. "It’s enough to tag a part of the herd."
Some 200,000 reindeer live in Norway, most of them owned by Sami people.
The Sami have in the past tried to attach reflective tape to the animals, but found that the glue was made ineffective by the cold.
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Finnish herders had experimented with a reflective spray, but found that the reindeers' fur became less effective at keeping them warm.
In September, Norway's Public Roads Administration began erecting lines of "disco poles", which emit loud noises and flashing lights along several busy roads, in an attempt to scare away elk, which would otherwise cause accidents.