PHOENIX — This winter’s El Niño-fueled storms are leaving the Arizona Department of Transportation and drivers with some bumpy reminders of the one-two punch our highways take from Mother Nature and traffic.
The good news is ADOT crews regularly examine state highways for potholes and address them as quickly as possible, making short-term patches followed by long-term repairs.
But conditions that lead to potholes will keep coming, including a storm forecast for early next week, meaning drivers should be keep eye out. How many potholes develop depends in part on how much rain and snow falls.
Potholes can pop up quickly when moisture seeps into and below asphalt, which can be stressed by the combination of freezing overnight temperatures and daytime thawing. Add traffic, and that pavement can break away.
The Flagstaff area usually experiences more than 200 daily freeze-thaw cycles each year, creating a challenge for ADOT maintenance crews in that region. They have stayed busy with pothole repairs since a weeklong series of storms swept across the state in early January.
But even in the state’s warmer regions, where freezing doesn’t occur as often, pothole repair comes with the territory after storms roll through. Given predictions of a wetter-than-normal winter, crews likely will face more bumps in the road.
“Our work doesn’t stop when the snowplows are put away,” said Brent Cain, the ADOT assistant director in charge of the Transportation Systems Management and Operations Division. “Our crews put in long hours to keep the pavement as smooth as possible. It’s a real challenge to keep up with Mother Nature and heavy traffic.”
When storms create potholes, highway workers make initial temporary repairs as soon as possible with patches made from a product called Universal Paving Material, which is heated, placed in the damaged area and tamped down.
More permanent repairs come after the pavement has had time to dry out. That work involves the use of a milling machine to remove a section of pavement around the pothole. In some cases the milled pavement is reused by placing it in an asphalt recycler machine that heats the material on site. A sticky oil is sprayed into the milled area being fixed before the recycled asphalt is placed on top. Crews finish the repair by using a heavy compaction roller to smooth out the pavement.
This type of work on Phoenix-area freeways almost always takes place at night, when there is less traffic. Along a busy freeway, ADOT’s goal is make repairs with most drivers never noticing the work taking place.
Drivers who want to pass along pothole locations on state highways can notify ADOT by visiting the agency’s website at azdot.gov and clicking on “Contact” in the upper right corner of the home page.
The annual cost of pothole and other pavement repairs depends on the severity of a winter season. ADOT usually plans on approximately 10 percent of its winter operations budget being spent on pothole repair.
Since Arizona has been experiencing drier conditions over many of the past 15 years, fixing potholes hasn’t been quite the same challenge. Depending on what Mother Nature and El Niño deliver in the coming months, that could change in 2016.