Boise & Garden City

It’s chipsealing season in Boise. Watch your windshields

Watch chipsealers in action in Boise

Ride along with an Ada County Highway District crew as they resurface roads in East Boise in August 2015.
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Ride along with an Ada County Highway District crew as they resurface roads in East Boise in August 2015.

North End residents found out this week that it is their neighborhood’s turn for the Ada County Highway District’s chipsealing.

From North 23rd Street to Fort Street, and Fort Street from State Street to North 16th Street are undergoing chip seal work. The same goes for North 17th Street to 1st Street from State Street to North 16th Street. Whitewater Park Boulevard to North 17th Street between State and Idaho streets are also getting the treatment, according to ACHD.

ACHD has a rotating schedule for chipseal projects, focusing on one of six districts each year.

The 2016 project began Sunday and could wrap up in late August or early September, according to ACHD.

Chipseal is not a favorite among residents, largely due to the exposed gravel that can raise dust, spray rocks and slow down driving. But, the process is cheaper and longer-lasting than asphalt. Asphalt costs almost 10 times as much as chipseal and often doesn’t last as long. An asphalt overlay would cost $20 per square foot while chipseal costs just 22 cents per square foot.

One of the frustrations drivers have with the process is the higher likelihood of getting your windshield, bumpers or brakes chipped by loose gravel. ACHD encourages motorists to reach out to them with complaints through email at or by phone at 208-387-6100. ACHD will then send a third party out to investigate the complaint.

The chipseal process

Step 1:

Preparation. This process starts in the early spring when highway district crews sweep roads and seal their cracks. Trees that will get in the way of chipsealing equipment are trimmed.

Step 2:

LMCRS-2H. That's the industry name for an oil product infused with polymers to make it extra sticky. A truck shoots the oil on each lane as the chipsealing process gets going for real.

Step 3:

Put the "chip" in chipseal. A truck loaded with one-quarter or three-eighths-inch rock particles follows immediately behind the oil truck, spreading an even layer on the oil.

Step 4:

Roll it in. Rubber-tire trucks, each one with nine tires in staggered alignments, drive over the rocks to set them in the layer of oil. The polymers in the oil help bind the rock to the oil. Clint Heckenlively, a ground crew chief for the district, said experts are always looking for ways to improve this process, including experimenting with steel drum rollers to push the chips into the oil. Excess rock is often left behind. Cars can push the loose rock into rows, especially at street corners, to the irritation of other motorists and especially bicyclists.

Step 5:

Fogging. After allowing five to 10 days for the chip-oil bonds to set up, a truck removes the excess rocks from the roadway. After that a truck applies a thin layer of oil - similar in composition to the bottom layer - on top of the chip layer. This step, known as "fogsealing," helps seal everything in place.

Step 6:

Stripes. A few days after the fogseal is applied, crews paint lane stripes on the new, very black road.