Unpaved roads comprise around 35% of American roadways, meaning millions of people use them daily.1 Unpaved roads have significant benefits. Namely, they’re cheaper to construct than paved roads, and they have fewer traffic fatalities.2
However, unpaved roads have problems like:
Let’s explore these problems, their causes, and how to fix them.
Unpaved roads are made from native soil, which is softer than pavement. To understand how much softer, consider this: Type II aggregate is a common subbase for paved roads, and R-value testing is a common way to test a road’s strength. During R-value testing, Type II aggregate tested up to 15 times stronger than native soil.
Soil makes unpaved roads prone to surface problems like potholes, ruts, washboarding, and loose material, which are all symptoms of erosion. At best, these problems increase travel times and damage vehicles. At worst, they cause serious accidents. To better combat soil erosion on unpaved roads, it's crucial to know what type of erosion you're facing.
Surface issues develop due to weather, such as rain and the freeze-thaw cycle. Weather-related maintenance can worsen these conditions—like when snowplows accidentally dig into the soil.
Normal traffic also erodes unpaved surfaces, especially in places where people slow down, speed up, or turn. That’s because speed changes create friction that damages unpaved roads. (Driveway entrances and intersections are prime examples.)
Finally, improper construction makes surfaces wear poorly over time.
Start by solving existing problems. Fill potholes and grade uneven surfaces to make the road safe and smooth. Depending on the extent of the damage, you may need to add material. Choose appropriately sized aggregate. Aggregate that’s too large creates an uncomfortable driving surface, while rain may wash away aggregate that’s too small.
You may also need to reshape the road’s crown or berms to improve drainage, especially in speed-change areas. Reshaping costs more and takes longer than simply grading the road, and you may have to close the road temporarily. However, reshaping can fix structural problems. That’ll save you time and money on maintenance in the long-term.
You can also prevent more issues by enforcing speed limits or setting lower ones. Slow and steady wins the race.
Hollywood producers love to film cars trailing dust on unpaved county roads, but dust isn’t glamorous. Inhaling it harms people’s health. It limits drivers’ visibility and coats everything from mailboxes to cars to plants. In fact, excessive dust kills plants because it prevents them from absorbing sunlight. Those are all reasons why we so deeply need road dust control.
Unpaved roads get dusty when hot weather dries out the road surface. Then, wind and passing cars lift those dry soil particles into the atmosphere. This dust worsens over time because more traffic on an unpaved road crushes soil and gravel particles into more dust.
Environmental factors also increase dust. For example, soils that are rich in clay are prone to produce more dust. And the wind has the power to blow dust up to three miles into the atmosphere and more than 5,000 miles around the world.3
Industrial activities like mining and farming produce even more dust. One study from the U.S. Department of Agriculture found that 76% of dust from a field travels more than 600 feet from that field before settling.4 So, if your unpaved road travels through an agricultural or industrial area, it'll always have some dust.
Permanently suppressing 100% of dust on unpaved roads is highly unlikely. That’s because dust comes from the environment, not just the road itself. However, you have several options to significantly reduce dust.
Chemical dust suppressants help manage unpaved road dust. Many types of chemical dust suppressants exist, so we’ll cover some of the most common ones.
Magnesium chloride and calcium chloride are cost-effective and work well in humid climates. However, chlorides don’t work in dry climates. They also pollute the environment and corrode vehicles and equipment. Petroleum derivatives and bitumen emulsions work in dry climates. With these methods, people put oil or tiny bits of asphalt on the road surface. Petroleum derivatives harm the environment, so many rural counties seek better options.
Organic dust suppressants are eco-friendlier than traditional chemical methods. They include everything from vegetable protein blends to the enzyme-based dust suppressant Surfa-Zyme.
Water is a natural, effective dust suppressant with no negative environmental impact. The downsides? You have to reapply it frequently—sometimes multiple times a day—and that gets expensive.
Soil stabilizers bind soil particles together, preventing loose dust from entering the atmosphere. Multiple types of soil stabilizers exist, including cement, polymers, and enzymatic soil stabilizers like Perma-Zyme. They each have different chemical properties, environmental impacts, and costs. So, it’s important to compare your options to find a soil stabilizer that works for your location and budget.
Poor drainage causes unpaved road problems like:
All three can make unpaved roads impassable, which can be life-threatening. Roads must always be clear so first responders can reach people during emergencies.
Additionally, drainage problems cost you money. Erosion washes away road material you’ll never get back, so you must pay to replace it. That material then clogs drainage ditches—making roads more likely to flood—and enters waterways where it harms aquatic wildlife.
People often think unpaved roads drain well because dirt absorbs water. However, road builders heavily compact unpaved roads, so most water runs off the surface and erodes the road on its way out. Design flaws also make roads retain water. These include insufficient or non-existent drainage ditches and failure to adequately account for rainfall, flooding, or elevation during construction.
First, add drainage ditches wherever possible. Most rural roads need drainage ditches to remove water. Consider partnering with local farmers. Constructing your drainage ditches to flow into their fields irrigates their crops and keeps your roads drier. If your road has drainage ditches, clear them of brush and debris each summer. Clear away snow in the winter, especially before the thaw melts it. You may also need to remove or groom overgrown grassy areas blocking water flow.
Installing culverts under the road removes water and reduces erosion. As a bonus, slightly exposed pipes double as speed bumps. (Make sure they can withstand the weight of vehicle traffic.)
Finally, consider how to build up low-lying or flood-prone sections of road. A steeper crown or a few extra inches of elevation may be enough.
Some unpaved road problems aren’t on the road itself. Rather, they happen alongside it. Roadside safety hazards include:
Rural unpaved roads are often surrounded by vegetation that blocks visibility. And the closer vegetation comes to the road, the closer local wildlife comes, too! That causes more accidents, vehicle damage, and injuries to both people and animals.
Even in flat, open places with good visibility, roadside hazards exist. For example, many unpaved roads don’t have shoulders, so motorists can’t safely pull over if they’re having car trouble or stopping for an emergency vehicle.
Roadside safety hazards usually stem from the environment and budget constraints. In some areas, building shoulders on the road is difficult due to geographic features or private property. After all, you can’t just slap a road on someone’s land. Budget constraints also make it difficult to prevent hazards. Trimming vegetation or installing emergency pull-offs costs money for equipment and labor.
Trimming vegetation to increase visibility costs time and money, but it’s essential. Don’t scrimp here! Instead, free up resources for regular roadside maintenance by reducing other costs. For example, you could switch to a dust suppressant that requires fewer applications.
When you can’t eradicate hazards, use signage to warn motorists. Deer crossing signs, reflectors near turns or embankments, and so on are simple, cost-effective, long-lasting solutions.
Speaking of solutions, we have one last tip: Look for products that solve multiple unpaved road problems at once, like Perma-Zyme. Perma-Zyme is an enzymatic soil stabilizer that treats roads to create a hard, concrete-like surface. This significantly reduces problems like:
Perma-Zyme treated roads last for 10 years or more with little to no maintenance. So, treating the road once frees up nine years’ worth of time and money to spend on other areas.
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