But ice roads are more than just frozen rivers. Road crews improve the ice road by taking advantage of the fact that ice floats. They drill holes in the ice and drive light trucks over them. The floating ice gives a little under the weight of the truck and forces water up through the holes where it spreads out to form a thin layer. This water then freezes and thickens the ice road. Road crews also maintain the road by plowing regularly, since open ice freezes more solidly than snow-covered ice.
Although ice roads are plowed like regular roads, they offer a different driving experience. Because ice has give, a wave is created under it as the vehicle drives on top. Driving too fast can create a wave strong enough to crack the ice, especially as you approach the shore. So the speed limit is about 10 miles per hour.
In May, the ice breaks up and is washed away into the sea. So, if you want to drive up to Aklavik or Tuktoyaktuk, to see the northern lights, you'd better plan on winter driving.