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Week of June 1, 2009
County spreads the good stuff around in annual roadway paving program
Cracking along the road surface can lead to potholes, or worse... | Early summer-like weather is allowing the King County Road Services Division to get a jump start on its annual road paving program, and this year there will be some difference in the paved surfaces as the division turns its attention to more residential streets.
“In recent years, we’ve focused on getting caught up with the most pressing pavement needs of our busy arterials roads in unincorporated King County,” said Division Manager Linda Dougherty. “Now this summer, we can do a combination of both high-traffic roadways and less-traveled neighborhood streets.”
Regular maintenance and pavement overlay keeps roads in good condition by preventing potholes and preserving the underlying road bed. And, repaving is much less costly than rebuilding a broken-down road.
King County has more than 1,800 miles of roadways to maintain and eventually these roads begin to show their age. The natural aging process begins with the appearance of cracks in the driving surface, which then deteriorate into potholes and, if left unaddressed, can lead to more serious problems.
Maintaining the driving surface and underpinnings of the county's road system remains a high priority for King County, and the Road Services Division has become more creative in the past few years as asphalt prices have increased and the division’s budget has seen reductions.
This summer, the county will be using two different resurfacing treatments:
- Hot mix asphalt, a two-inch layer of asphalt mixed with crushed rock, will be applied to roads with high-traffic volumes; and
- Chip seal will be used on the residential streets. It uses the same materials, but they are applied in two thinner layers. The asphalt is sprayed on the prepared roadbed first, then rock chips are spread on top of that and a roller sets the rock into the asphalt. Finally, the roadway is swept to remove loose material.
...water can seep through the surface cracks to wash out both the pavement and supporting subsurface. | “It’s been several years since we used chip seal on county roads, because in recent years we were more focused on arterial roads that need the thicker pavement,” said Dougherty. “Chip seal is commonly used by local cities, and it’s very cost-effective on the residential streets.”
Dougherty said the chip seal products the division will use this summer have been improved in recent years. The rocks are coated prior to applying them to the asphalt and they bind more strongly together.
Between June and October, the county will be resurfacing approximately 45 miles of unincorporated roads. Most of the resurfacing is done in short stretches, so those miles are spread across many locations in King County.
A significant amount of this year’s paving will occur on Vashon-Maury Island. There will be some delays and some parking restrictions on the island, as crews work on Vashon Highway and areas around the ferry dock on the north end of Vashon. Notification of the delays and parking restrictions will be posted in the affected locations about 48 hours in advance of the crews’ arrival.
In addition to Vashon, the south county program will repave roads in the Maple Valley area, East Kent, and the Enumclaw Plateau. This year’s north county program will focus on unincorporated roads in the Kingsgate and Eastgate areas.
Even though most of the paving takes place along short spans of roadway, it will take more than 54,000 tons of asphalt products to do the job. The 2009 overlay budget is approximately $7 million.
There is a lot of prep work necessary to get the roadways ready for repaving that happens weeks before the asphalt arrives on the scene. Preparations for this year’s program include patching cracks and potholes, grinding away worn-out surfaces, rebuilding the roadbeds and shoulders, and repairing drainage systems before the new pavement goes down.
The prep work has to be closely coordinated with the overlay crews, because nobody wants to cut through a newly paved road if it can be avoided. Any cut or crack allows water to seep into and under the road surface, which can speed up deterioration of the entire road system – not just the driving surface.
“We want to do as much work as we can below the road surface before the new pavement goes on,” said Dougherty, “because the longer you keep from breaking through that surface, the longer the road will last and the safer it will be for our residents.”
Time to prepare again for lane closures on the Interstate 90 bridge over Lake Washington.
| In just about a month, the Washington State Department of Transportation (WSDOT) will begin the second part of its joint-replacement project on the Interstate 90 bridge.Westbound congestion for the July project is expected to be much worse than when the first part of the project was done in May, because this time five lanes of traffic will be funneled into two lanes for several weeks. WSDOT is teaming up with King County Metro Transit to offer special vanpool incentives to help reduce the number of vehicles traveling across the bridge this summer. The incentives are open to commuters starting a new Metro vanpool on routes that routinely cross the I-90 or SR-520 bridges in either direction or travel on I-405. Eligible vanpoolers in new groups that start by July – the application deadline is June 17 – will receive free Metro vanpool fares for three months. Five or more commuters who share the ride to a park-and-ride can get signed, reserved spaces at the lot or garage by forming a Metro vanshare group. WSDOT will pay the new vanshare group’s fees for three months. The first 3,000 commuters who register on RideshareOnline or who update their registration will receive a $20 gift card. For more information, visit this website or call (206) 625-4500.
The transit tunnel is a convenient way to travel through downtown Seattle.
| As part of Metro Transit’s summer service change that started this week, the Downtown Seattle Transit Tunnel (DSTT) is now open from 5 a.m. to 1 a.m. weekdays and Saturday, and from 6 a.m. to midnight on Sunday for all current tunnel bus routes. When the DSTT is closed, tunnel bus routes operate on Second, Third, Fourth or Fifth avenues in downtown Seattle.The new hours are in preparation for the start-up of Link light rail service on July 18. Light rail will serve all tunnel stations except Convention Place.
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