Potholes have invaded the city of Tucson. We have all driven through and around them, trying to avoid what could be potentially damaging.
What exactly are these annoying little, and sometimes big, holes in the street? Here is a four-step process of how they form.
1. Rain and snow seeps into preexisting cracks in the road, weakening it.
2. When it is cold outside this water freezes and expands and as it thaws it shrinks, which enlarges the cracks in the road.
3. After awhile, the ground below can no longer support the heavy traffic, and it collapses.
4. As cars continue to drive over the potholes, they become bigger.
You can also take a look at this explainer video.