Road Commission: Pothole patching 101

When it comes to potholes, the Road Commission for Oakland County (RCOC) often takes care of the worst first.

RCOC has jurisdiction over Haggerty, Orchard Lake, Middlebelt, 12 Mile, 10 Mile east of Orchard Lake Road and west of M-5, and Eight Mile between Grand River and Farmington Road. Especially at this time of year, the agency’s patch crews are trying to patch the worst holes (sometimes referred to as “wheel breakers”) as quickly as possible.

“Because we’re focusing first on getting the wheel breakers as quickly as we can, our crews will sometimes skip the smaller holes,” Highway Maintenance Director Darryl Heid explained in a press release. “Sometimes the public does not understand that we’re doing this so that we can get around the entire system as quickly as possible to get the most serious potholes filled. If we took the time to patch all the smaller holes at the same time during these efforts, we would never make it around to all the wheel breakers.”

Heid noted once crews have made it around the main road system to get the worst holes, they will come back to “tighten up” the system by patching the smaller holes. He added safety dictates they will move into subdivisions in townships only after crews are done patching all the main roads, which carry the most traffic moving at the highest speeds.

Additionally, the pothole patching material available during the winter and early spring, while the best material available during those times, is not as durable as the “hot mix” material that becomes available later in the spring.

“We use what is called ‘cold patch’ material in the winter,” Heid said. “This is material that is specially designed to remain flexible in cold weather and that can be used in both cold temperatures and we conditions. We use ‘hot patchers’ to heat the material, so it is more malleable and therefore fills in the potholes more completely.”

He added that the cold patch does not last as long as the hot patch manufactured by asphalt companies. However, the asphalt companies close their plants every year in about November and do not open them until typically mid-April, so hot patch is only available in the spring, summer and fall.

“One of the challenges of cold patch is that, in order to be used in the winter, it must remain malleable at all times,” Heid said. “That means it never fully hardens, even after being placed in holes. While this property is necessary to for the material to be used during cold weather, it also reduces the longevity of the patch.

“People sometimes ask why we bother patching in the winter if we know the patches are less likely to last. The answer is that potholes can be dangerous and destructive, and we cannot simply ignore them during the colder months. So, we patch them with the very best material available at that time of year, knowing we’re likely going to have to re-patch the holes with hot patch when it’s available. That is simply the reality of pothole patching in Michigan.”

Another question people often ask about pothole patching, Heid said, is why crew members don’t spend more time tamping down the patch material.

“We do not have the luxury of having the time to devote to each individual pothole,” he said. “We have a large road system that is in fairly poor condition due to decades of underfunding, and there are many potholes. If we spend several minutes tamping every single patch, we would never make it around to the entire system. So, the employees give the patch a quick tamp and move on. The follow trucks do their best to roll over the patches with their tires, which applies a lot more pressure than the employee can with a shovel.”

Potholes form when cracks form in paved roads, allowing water to seep into the road. When temperatures drop, the water freezes and expands. When temperatures rise again, the ice melts and the water drains, leaving a void in the road. When cars drive over the area, the road surface collapses above the void, causing a pothole. Older roads, with more cracks, are far more prone to potholes.

“We are out patching potholes every day we aren’t responding to snow and ice. The public can help by letting us know when they see potholes that need patching,” Heid stated.

To report a pothole, call the Road Commission’s Department of Customer Services toll free at 877-858-4804. Potholes can also be reported online at (click on “Contact Us”).