ID-55 Smiths Ferry project transitions to summer work schedule

Spring construction is wrapping up on Idaho Highway 55 between Smiths Ferry and Rainbow Bridge. Thursday, May 27th marks the last day of planned full road closures until September. Friday through Monday during the Memorial Day weekend, both lanes of the highway will be open. Then Tuesday, June 1st, our summer construction schedule begins.

This project will help improve safety and mobility for drivers by widening shoulders, minimizing roadway curves, and installing guardrail in certain locations.

“Our spring construction started in mid-March, and with full road closures Monday through Thursday from 10 a.m. to 2 p.m. crews were able to safely blast rock away from the hillside,” said Project Engineer Alex Deduck. “In two and a half months crews excavated and removed nearly 55,000 cubic yards of material, that’s more than 4,500 truckloads. We’re close to a third of the way through the project now and appreciate everyone’s patience and cooperation as we make this a safer drive.”

Crews will continue their work on the highway this summer. June 1 through Labor Day drivers should plan for one-lane alternating traffic day and night Monday through early Friday morning. Both lanes will be open on weekends Friday through Sunday to accommodate busy summer travel.

Watch the video below to see the progress made so far.

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Thank you for your patience as we improve the safety and mobility of ID-55.

Blasting operations underway on ID-55

Rock blasting is underway between Smiths Ferry and the Rainbow Bridge as road construction continues on ID-55.

The goal is to make this narrow, curvy mile-long stretch of state highway safer, by building wider shoulders, adding guardrail, and straightening the road.

140,000 cubic yards of rock need to come off the canyon, and it’s happening one controlled blast at a time. How do they do it? It takes a lot of work and careful planning.

Strategically spaced holes are drilled into the rock differing in size and depth depending on the situation, then the explosives are placed inside.

“We’re using a nitro glycerin based dynamite as a primer, and then we use ammonium nitrate as a blasting agent,” said Blast Operator Ryan Miller. “Each hole is timed, a 40th of a second. We shot that in a V, and the reason it stayed on the hill is because we shot the center first, and kind of sucked it uphill.”

Each blasting design plan is closely reviewed.

“The whole idea is to move the rock in the direction we want it to. We don’t want to launch into the river, fly rock is our enemy,” Miller added.

Through late November, weather permitting, the work zone is closed to traffic every Monday through Thursday from 10 a.m. to 2 p.m. so crews can safely blast and haul away the rock.

Drivers are urged to plan around the closures or use US-95 as a detour.

“We don’t want people or cars traveling through the work zone during blasting. It’s also an incredibly tight work zone with the river off to the east and the rock faces out to the west. So giving the contractor that four hours is really letting them be as efficient as possible,” said Project Engineer Alex Deduck.

Steel containers and temporary barrier keep the falling rock from getting in the travel lane, and protect the crews working in this steep canyon. When the road is not fully closed, one lane is open to alternating traffic.

“Now that we’ve reduced it to one lane it’s even tighter, and just a hard area to work in,” Deduck said.

This winter, construction will pause and both lanes will be open.

In the spring, blasting picks back up with full road closures Monday through Thursday from 10 a.m. to 2 p.m., and during the busy summer, one lane will be open to alternating traffic Monday through Friday morning. Both lanes will be open Friday afternoon through Sunday.

You can learn more about the project and sign up for updates at itdprojects.org/ID55smithsferry. The project is expected to finish in late fall 2022.

For the latest road conditions, be sure to download the Idaho 511 app or visit 511.idaho.gov.

Nampa to Marsing, ID-55 preservation projects begin after 4th of July Holiday week

Map of seal coat project on ID-55 from Nampa to Marsing

A pavement rehabilitation project between Nampa and Marsing is scheduled to begin July 9 and conclude in late July/early August. Work will seal the pavement and extend the life of the roadway.

The first phase, a six-mile micro-seal from Nampa-Caldwell Boulevard to Farmway Road, will occur in the evening (10 pm – 5 am). Work is expected to conclude the week of July 16.

The second phase, an eight-mile chip-seal from Farmway to the Snake River Bridge at Marsing, will occur during daylight hours. Work is expected to conclude in late July.

During both phases, motorists can expect reduced speeds and up to 15-minute delays as traffic will be periodically reduced to one-lane with a pilot car guiding traffic. Where work is occurring, intersections will be controlled by flaggers with minimal delays. Motorists are encouraged to drive with caution through the work zone.

Schedules are subject to change. The contractor is permitted to work weekends. For up-to-date construction information, visit 511.idaho.gov.