About Street Maintenance
City street infrastructure is aging and significant funding is needed for street and sidewalk maintenance. The City’s transportation system is one of the most valuable assets for connecting the community and attracting new investment. Deferred maintenance drives repair costs higher. State and Federal funding for maintenance of the City’s streets has been reduced in recent years, while costs continue to rise, leaving the City with inadequate resources to preserve and maintain streets.
An ounce of prevention
The City’s transportation system includes approximately 101 miles of streets with an estimated value of $196 million (replacement cost). From the moment of construction, streets suffer wear and tear from traffic and weather. Streets need ongoing maintenance to preserve conditions. As a rule, an ounce of prevention is worth a pound of cure—it is less expensive to maintain streets than it is to repair or replace them. Using a “Best-first” approach to preserve roadways now, will extend the life of road surfaces and save costly reconstruction.
Delayed maintenance drives repair costs higher
Today, most of the City’s streets are in good or satisfactory condition. However, some Tumwater roads are in fair condition and some are already failing. Without proper maintenance, streets that are now in satisfactory condition will continue to degrade. The longer maintenance is delayed, the more expensive the repair.
A pavement management system is used to assess and prioritize treatment of City streets. This system is designed with a more cost-effective “Best-first” approach. Recognizing it is better to treat streets with lower-cost, preventative treatments than to wait until the street condition deteriorates to the point that major rehabilitation or reconstruction is required.
Funding street maintenance
As the City grows, so does the road system. Tumwater now has 101 miles of streets. And the ongoing annual cost to preserve and maintain street infrastructure continues to rise. It would take $31.8 million over the next 10 years to bring Tumwater's current transportation system to industry standards and continued funding to maintain them in good condition. Preventative Maintenance (crack sealing and seal coat) for the approximately 9 miles of street to preserve conditions would cost $6 million. Rehabilitation (patching, overlay and surface reconstruction) of the poorest 2.5 miles of roads would cost $18 million.
Roadway treatment costs per mile (Avg. 32’ width of street)
Preventative Maintenance - Chip Seal, $6/square yard, 1 mile = $115,000
Rehabilitation - Overlay, $35/square yard, 1 mile = $660,000
Reconstruction, $100/square yard, 1 mile = $2,000,000
With proper maintenance, life expectancy of a new road is 30 years. It is better to maintain streets with lower-cost, preventative treatments than to wait until the street condition deteriorates to the point that major rehabilitation or reconstruction is required. In general, the longer maintenance is delayed, the more expensive the repair.
Maintenance measures like crack sealing costs about $1 per square yard and chip seals costs roughly $6 per square yard.
Crack Sealing is the filling of moderately-sized cracks with hot liquid rubberized asphalt. It is the lowest cost of all treatments and is used to extend pavement life at the earliest possible time. It seals out moisture and chemicals and can be applied to any street, new or old.
Chip Seals (or seal coating) are the application of a special protective wearing surface to an existing pavement. In this method, gravel chips and liquid asphalt are spread on the existing pavement and rolled in place to seal the road surface. This is a low-cost preventative maintenance method that extends pavement life, seals and re-establishes surface traction. These are generally performed on a 7-8 year cycle on well-traveled roads.
Pothole Repairs and Asphalt Patches. When a small isolated section of a street fails, it forms a "pothole." Potholes typically form when water has seeped under the pavement surface, creating pockets of water that fracture the surface when traffic passes over the road. Individual potholes are temporarily repaired by filling them with a cold-mix asphalt. If a section of roadway has repeated and numerous potholes, it is a sign that the sub-base under the road surface has failed and the road needs to be reconstructed. When a street is generally in good condition but there are isolated sections that show signs of failure, asphalt patching is performed to improve the overall condition of the street. This process is similar to asphalt overlay (above), but on a smaller scale. Failed sections are saw cut, removed, and repaved. Cost varies depending on the extent of patching and repairs needed.
Asphalt Overlay costs approximately $35 per square yard. If large areas of a roadway are showing signs of structural failure such as potholes or alligator cracking, these areas are ground down to the good pavement base. This is followed by a new hot-mix asphalt pavement layer (overlay) using a paving machine, extending the life cycle of the original pavement. Asphalt overlays are generally performed on a 15 to 20-year cycle.
Reconstruction of a street costs roughly $100 per square yard. When a roadway has reached the end of its life cycle and can no longer be rehabilitated using the above methods, a new road must be constructed. First, all existing pavement is removed. Then this pavement is ground up and mixed with the remaining road base soil, and re-graded and compacted in place. Lastly, new pavement, consisting of hot-mix asphalt, is applied with a paving machine. Reconstructing a street is the most expensive method, but necessary when paving and base material have failed.
For more information, contact the Public Works Department at (360) 754-4140.