The cost of road repairs depends on a number of variables, including the location, type of construction, the number of lanes, lane width, and the condition of the road. Road work typically cost more in urban areas than rural areas. Keeping a road in “good” condition is less expensive than rebuilding a deteriorated road.
Below are some common types of road construction projects. The costs mentioned in the descriptions below are estimates per lane mile. Please note that projects can cost more or less depending on the cost of materials, schedule, traffic volumes, environmental impacts and other factors.
Pulverize & Resurface
When a road is in “poor” condition, it may be rebuilt through a process of pulverization and resurfacing. WCRC uses a machine called a pulverizer which is capable of breaking up 6-10 inches of existing asphalt pavement. WCRC then recycles and compacts the pulverized asphalt to create a new road base. After establishing the new road base, crews apply two layers of new asphalt to create a smooth, long-lasting road surface. A pulverized and resurfaced road will last 10-15 years and costs approximately $300,000 per mile.
Mill & Resurface
Roads that are in “fair” condition are good candidates for a mill and resurfacing project. During a typical mill and resurfacing project, one layer (1.5–2 inches) of existing asphalt is removed (milled) and the road is resurfaced with a new layer of asphalt. A milled and resurfaced road will last around 7-9 years and costs approximately $170,000 per mile. If the road has deteriorated into “poor” condition, milling one layer of the roadway is usually not enough to improve the ride condition and prevent future deterioration and potholes.
Chip Seal / Seal Coat
Chip sealing is a relatively low-cost surface treatment that seals and prevents water from seeping into the roadway. Chip sealing helps prevent potholes and protects the road surface from the damaging effects of weather, sun, and traffic. A chip seal can help extend the life of a road by 3-7 years and costs approximately $25,000 per mile. WCRC aims to chip seal roads that have been recently pulverized or milled in order to extend their lifespans.
Bridges – Routine Maintenance & Reconstruction
Washtenaw County is home to 119 bridges, many of which were built in the early 1900s. Each year WCRC performs preventative maintenance on bridges with available resources. However, a bridge must be completely replaced if it is deemed structurally unsound during WCRC’s routine inspections.
Bridge replacement projects differ in scope depending on the type, size, traffic volume, and environmental surroundings. A bridge replacement will typically take 3-6 months to construct and can cost anywhere from $500,000 to $3 million depending on the size of the project.
Culverts – Repairs & Replacement
WCRC is also responsible for the maintenance of over 2,000 culverts. Culverts allow water to easily flow underneath a road. Culverts are prefabricated and can be round, oval or box-shaped. They can span between 1 to 20 feet. Similar to the Washtenaw County’s bridges, many culverts were built in the early 1900s, have exceeded their lifespans and require repairs or replacements.