Zimmerman Trail will close for the next three weeks while crews stabilize cliffside rocks above the road, cutting off a direct route between the West End and the Heights for the more than 13,000 drivers who use it on an average day.
Watch crews on the rims here:
Crews are shoring up the cliffside rocks to keep them from falling onto the road and into the houses below. The work is mostly centered in an S-shaped curve starting at the slow down sign as you drive up the Rims.
The project aims to get ahead of a problem. Over the past year, the city worked with an engineering firm, TerraCon, which conducted an assessment and investigative work on the segment.
The firm identified an approximately 70-linear-foot-wide rock segment — a large shelf just above the roadway — showing signs of undermining and stress cracking, conditions that could cause rockfall onto the road and even into the houses below.
The city bid the project in September.
Related coverage:
Billings working to prevent rockfall along the Rims near Zimmerman Trail
"It just creates a hazard," said Will Robbins, a project manager for the Billings Public Works. "We're just going to try to mitigate that best we can and make things safer."
Robbins said TerraCon identified the most susceptible area of rocks — the segment with the greatest potential to move or fall — though no one can say exactly when that might happen.
"When it would move or when it's going to fall, no one could really say. It's just what they determined to be, the have the highest potential of some time in the future," Robbins said. "So that's why it just creates a hazard for anything on the roadway and everything down below. There's lots of houses down below."
Robbins explained how crews will keep the rocks in place.
"They'll drill into the rock about 20 feet. They'll put steel anchors in, grout it into place, put plates out on the front," Robbins said.
The crews will drill past a crack believed to sit behind the loose segment, anchoring into solid bedrock. They'll then add shotcrete and cable as another safeguard.
"There's the cable and it'd be a kind of a suspenders-type thing to catch that," Robbins said.
Finally, crews will cover the work with dyed shotcrete to help it blend into the surrounding Rims.
The city will also use the closure to complete other maintenance while the road is shut down, which crews say will help them avoid future closures for that work.
That includes repairs to a guardrail where drivers have bumped or driven into it, along with geotechnical drilling above the road for another project Robbins said he can't discuss yet.
The three-week window is designed to give the contractor the most flexibility while keeping workers and the public safe, Robbins said, adding there is a chance the work could finish sooner. He said the timing was driven by when the contractor was available.
"We'll get it opened up as soon as possible. I realize it's an inconvenience for everyone," Robbins said.
For some, it could be more than an inconvenience — it could cost local businesses.
For Ace Hardware Boutique employee Sam Brewer, the closure adds time to an already tight commute.
Brewer, who lives in Shepherd, said the detour could add significant time to the drive.
"I'd be off at five and I have to pick my son up in Shepherd by six. And I'm really nervous that it's... gonna be a few late nights getting there," Brewer said.
Amy Piercy, who works at the boutique, said the shop relies heavily on customers coming down Zimmerman Trail from the Heights, and the closure could cut into the foot traffic the business depends on.
"We probably won't get as many people who just happen to drive by and say, 'Oh, I'm gonna go... in here and check out the boutique,'" Piercy said.
Piercy said the city has advertised the closure well in advance, so drivers who use the route are likely already making alternate plans.
Still, Brewer said many people may not grasp the full impact until the closure takes hold.
"I don't think people realize... how much it's gonna affect them until it's actually here. Like, especially traffic," Brewer said.
