ROVANIEMI, Finland — There's good news for Rudolph and his friends — an app is helping officials reduce the number of reindeer killed in traffic accidents in Finland.

Some 300,000 reindeer freely wander the wilds of Lapland in Arctic Finland. About 4,000 are killed every year through road accidents, officials say, and compensation to reindeer herders can be expensive.

Most of the accidents occur during the dark winter months when the animals are hard to spot.

Several methods to cut road kill have failed, including spray-painting antlers with fluorescent colors, hanging reflectors on reindeer necks and using movable traffic signs to warn of reindeer as they wander through the lichen-covered fells.

In their latest attempt, officials are using a smartphone app called “Porokello,” Finnish for “Reindeer Bell.”

And it seems to be working — at least last month, when there were 300 fewer reindeer accidents on the roads of Finnish Lapland compared with the same month in 2015.

A simple, one-button interface allows drivers to tap their smartphone screens to register any reindeer spotted near roads.

Using GPS technology, it creates a 1-mile warning zone that lasts for an hour and warns other app users approaching the area.

“If there are reindeer, (drivers) reduce speed,” said Jaakko Ylinampa, head of a local business center in Rovaniemi. “When they have passed the warning place, then they can get back to the normal speed again.”

Reindeer often wander onto roads that cut across grazing grounds rather than plowing through the deep snow, said Anna-Leena Jankala, whose family has a reindeer farm in Narkaus, 25 miles south of Rovaniemi.