Johnson County Public Works and Infrastructure is responsible for the maintenance and construction of the Gravel Roads in unincorporated Johnson County. They are a vital first link in the local economy and are more than a third of county maintained roadways.
Gravel Road Maintenance
To reduce dust and loose rock on the road surface, only minimal blading of gravel roads is performed during dry weather. This may result in a few more chuck holes and wash board areas. However, the net result will be a driving surface that is safer for the traveling public. The grader operator may windrow loose rock on the road shoulder. Motorists should be careful to avoid driving on this windrow.
When we blade our gravel roads we try to wait until after it has rained so they are easier to blade. A good blend of rock, sand and clay makes a good surface material and the clay is cohesive. When moistened the clay becomes sticky and is almost impermeable to water flow and has low strength when wet. The fine sand and fines fill the voids between the larger stones so the mixture can be compacted. If we are adding a new layer of rock (usually 2"-4") to the road we bring our own water and wet the rock mixture as needed during the blading operation.
We cut the existing surface 2” to 6” to get a good blend of rock and fines and we ensure that we are creating a crown that is 5” to 7” higher than the shoulders. The crown in the most important design element of a gravel road. The crown improves drainage and ease of maintenance and this degree of slope should drain the surface water without washing off the surface material.
As a gravel road is used its original shape changes. The crown will become flattened and chuck holes will develop. Surface materials are eventually blown, plowed or washed away. The road surface and shoulders must be smoothed and reshaped with a motor grader as often as necessary for the amount and kind of use the road receives.
Road dust is essentially limestone dust that is kicked up by traffic traveling on the road. Tires grind the limestone on the road and make a continuous supply of fine material. Once the dust is kicked up by traffic it is blown by the wind. Houses downwind from the prevailing wind will have more dust than those upwind. In Johnson County, road dust is more of a problem on the north and east sides of a gravel road than it is on the south and west sides of the road. The Public Works Department recommends that all houses be built at least 300 feet from a gravel road in order to reduce some problems associated with road dust to a reasonable level.
Many people do not realize how serious the dust problem can be until living in a new house for a number of months. The Public Works Department has seen a trend that people are not satisfied with living on a gravel road for an extended period of time. Many people expect that they can leave their windows open and enjoy the country air. However, they later find they may need to keep their windows closed to prevent road dust from entering the house. Although dust is not considered a carcinogen, it can pose health problems for persons with allergies and other respiratory problems.
You should be aware that there will be traffic increases on most roads in the rural area. Most gravel roads are section line roads that occur at one-mile intervals. These section line roads on the county's long-range plan are scheduled to be major arterial roads. This means that as the county develops, the gravel roads will eventually turn into 4-lane roads. The County does not have a program to upgrade gravel roads to blacktop roads or 4-lane roads with county tax money. These improvement projects are normally made after the area is annexed. The cities usually form benefit districts and the adjacent landowners pay for the cost to upgrade the road. If the area is not annexed, it is unlikely that the County will upgrade the gravel road to a blacktop road.
County road crews are responsible for snow removal and ice control during adverse weather conditions. Crews are ready to respond 24 hours a day 7 days a week. During snow removal operations, crews focus on clearing and maintaining paved main line roadways. When mainline roads have been cleared and treated secondary paved roads and finally paved subdivision streets are addressed. The County does not treat gravel roads with salt or sand, however we will attempt to blade off the snow when accumulations are greater than four inches or when drifting becomes a problem. The Public Works Department can be reached during snow removal operations by calling 913-715-8353.