Due to the extreme temperature fluctuation we have here in Canada, our asphalt can take quite a beating. The freeze/thaws we experience have such a detrimental effect on your pavement. Water gets into the cracks, freezes, expanding the crack further and causes a spider webbing effect which can lead to potholes.
Routing is a process where we use a routing machine (with a saw blade) to open up cracks and level out the sides of the opening so that the hot liquid asphalt compound can evenly adhere to the opening. This asphalt compound is more pliable than the pavement itself which allows it to expand and contract with the weather, thus preventing more damage. Done properly, routed and sealed cracks can prevent the problem from spreading and preserve the life of your asphalt.