It's to protect the road from damage! (Not so vehicles won't slide on the ice...)
Islanders find it easy to recognize visitors on the ice road from their big smiles — and often unfortunately — by their excessive speed. Islanders, on the other hand, generally keep to the speed limit because they know the repercussions of driving too fast, and they want the road to be safe and to last as long as possible!
There has been a lot of traffic on the ice road over the past two weeks, and yes, there have been speeders who probably didn't understand the damage they might be causing. The cracks above are not dangerous yet, but they do show wear and tear to the road.
The dedicated people who manage the Madeline Island Ice Road take great care to keep us all safe. The ice road is a gift, especially to the island's year-round residents, so let's all do our part, be safe, and keep to the speed limit!