By: Cook County Highway Maintenance Superintendent Matt Nesheim

“Dust in the Wind.” The lyrics of that infamous song by Kansas came to mind often while checking roads this June. Many Cook County residents are familiar with billowing clouds of dust trailing their cars down gravel roads, along with the bone-rattling experience of driving on a washboard-stricken hill.

Of the 297 miles of county-owned roads, just over 200 miles are gravel. This means that if you live in Cook County, you likely drive on gravel regularly and have encountered road conditions that caused you frustration. We can relate.

We deal with various issues when addressing maintenance on our gravel roadways. Not all gravel roads are created equal. Subgrade – or what’s beneath the surface – often determines the health of the driving surface on top and, as many residents know, the county deals with less-than-desirable subgrade materials on many of our roads.

Proper crown and ditches allow moisture to leave the road as quickly and uniformly as possible to avoid potholes, ruts, and washout. Unfortunately, many of our gravel roads are inadequately ditched, an issue we address a little bit each year.

Surface gravel must consist of a proper mix of aggregate and sand, bound together with fines (also known as “binder” material). But, if the road is well-traveled in dry conditions, the mix starts to separate, larger gravel (“float”) is thrown to the edge of the lane, and the binder becomes airborne. The faster the traffic and the higher the count, the more binder is lost and washboard conditions form.

Furthermore, drought conditions prevent basic road maintenance activities. Grading a dry road surface creates more issues than it solves, causing more dust and more corrugation. Thankfully, Cook County has received a few inches of rain in July. Moisture in the road allows us to cut to the base, mix the surface gravel, maybe add a lift with a few loads, and create a more enjoyable driving experience. But, again, that only lasts so long.

Chemical options help stabilize the surface gravel and cut down on dust. Cook County annually contracts for the application of calcium chloride on most county roads. Judging by the call volume at the highway department, it’s obvious that many residents look forward to this treatment.

Calcium chloride is hygroscopic, which means that it attracts moisture in the gravel and adheres its component parts. A well-graded road treated with calcium chloride can drastically cut down on short-term maintenance requirements. Calcium chloride soaks in and binds to the road surface, causing minimal rust damage to vehicles. Likewise, it causes minimal impact to the surrounding watersheds due to a slow and diluted release.

Unfortunately, calcium chloride costs have gone up drastically in recent years. In 2023, Cook County paid $1.48 per gallon, up from $1.01 in 2019. That’s almost 50% and that adds up on 200,000 gallons. Plus, despite the benefits listed above, it’s not always obvious that we’re getting a good deal; we often don’t receive our product until mid-summer, and by then it’s only a few months before the roads are frozen and snow-covered again. We know, however, that many residents have respiratory issues and most everyone appreciates the relief from drought-related dust. The maintenance crew also certainly appreciates a road that holds together.

As you enjoy the miles of gravel on county roads through the rest of summer, please reflect on what we all pay for the luxury of dust control. And, if there is washboarding on a hill near you, know that we will be out grading after the next rain. Same old song.

County Connections is a column on timely topics and service information from your Cook County government. Cook County – Supporting Community Through Quality Public Service.