News & Press Releases

Monday, June 14, 2010
Chipsealing underway

   Chipsealing is an annual sign of summer and is now underway.  This year about 250 miles of road will be chipsealed in Ada County.  Residents impacted by this year's work will notice that the chip size on residential roads will be smaller compared to what was used in their area before, creating smoother roads.  The chipseal process is also part of an effort to give more room to outside travel lanes to provide more space for bicycles and motor vehicles to share the road.  This year's work has been delayed due to rain, but chipsealing is happening this week.

   Smoother roads:  The Ada County Highway District (ACHD) chipseals each road in Ada County every nine years.  The last time the roads on this year's schedule got work, the size of the chip used on residential roads was three-eighths of an inch. This time around those roads will get a smaller, one-fourth inch chip which will make the streets noticeably smoother.  Larger roads get a three-eighths size chip, because bigger chips hold up better to heavy traffic and provide good traction during icy winter conditions.

   More room for bicycles: The chipsealing process includes repainting traffic lane lines on roads.  This year the ACHD Traffic Department will look for locations where the lines can be repainted so there is more room for bicycles on the shoulder.  One location that will have more space for bicycles is Overland Road between Latah Street and Vista Avenue.  Extra room for bikes is possible in locations where center-turn lanes and inner-most travel lanes can be narrowed slightly.  Experience has shown that less width on those lanes will not reduce vehicle safety, and provides a low-cost widening of bicycle space. This effort is part of ACHD’s Roadways to Bikeways Plan, a strategy approved by the ACHD Commission a year ago to improve bicycling facilities.

      The general areas where chipsealing will take place this season are:

• West of Ballantyne Lane, east of Can Ada Road and north of Ustick Road
• North of Overland Road, east of Orchard Street and west of Federal Way

ACHD crews will be chipsealing today in the area south of Emerald between Orchard and Roosevelt and  Franklin.  If you'd like to find out the crew's exact location please contact Robbie Johnson at 860-6628.

   More on chipsealing:  Chipsealing remains the most cost-effective way to maintain the county’s nearly 2,200 miles of local public roadway.  The cost for chipsealing is around $23,000 a mile.  Chipsealing saves taxpayer dollars because it protects the road from deterioration and greatly delays the need for a new asphalt overlay to repair a deteriorated road.  At this time, asphalt overlays (new blacktop) cost around $208,000 per mile.  Applying a chipseal on top of an overlay also extends the life of the overlay. 

   To apply the chipseal, an asphalt truck sprays the road with liquid asphalt.  Right after that, a spreader applies rock chips.  Then a rubber tire roller sets the chips into the fresh oil.  ACHD follows each chipseal with a fogseal that helps set the chips and controls fly-rock and dust.  Motorists should drive slowly in newly chipsealed areas to prevent flying rock.  Please see the attached brochure for more information.

   Because of ACHD’s chipsealing practices, Ada County roads are rated some of the best in the Northwest.  Chipsealing is done around the country, including other parts of Idaho.  More chipsealing information, as well as maps of the areas being treated this year, is available on the ACHD Web site at  For updates on chipsealing, residents can call 345-7880.

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