For the past few days, crews have working to expose a hidden hazard along Sierra Drive in Kaimuki.

Motorists may not have known how unstable the hillside is, since it was hidden by thick vegetation.

On Wednesday, crews worked to loosen rock and remove an overgrown banyan tree to get them access to the area that needs to be scaled back.

The plan calls for crews to cut four feet into the hillside.  The area will then be stabilized using netting, pins, and concrete to make sure nothing else comes down.

"We have to do whatever it takes to stabilize the hillside," said Chris Takashige, director of the Department of Design and Construction.

The city has actually spent the last decade surveying areas around the island that threaten public safety and public property and only last month finalized its list.

It has completed one project -- a dangerous drive in Pupukea.

A second phase in the same neighborhood is about to get under way.

Next on the list is a section in urban Honolulu.

"We have Punchbowl and Prospect next on the list, so as money becomes available we have begun to work on them," Takeshige said.