For the second time in two months, vandals have knocked out dozens of traffic cameras across Oahu by ripping out the fiber-optic cables that support them under the H-1 freeway.

The vandalism, at a site near Middle Street, disabled feeds from more than 30 traffic cameras, including 18 in Kaneohe and at least 16 in Pearl City. Among those knocked out in Pearl City are several that normally show traffic conditions on H-1.

Officials discovered the latest damage at 2 a.m. Wednesday, and copper thieves are once again believed responsible — even though city officials say there was no copper to be stolen there.

As a result, drivers who use the city’s official website or GoAkamai.org to view traffic conditions in those areas will instead find dark screens; frozen, outdated images; or "Image Temporarily Unavailable" messages. The cameras will likely will stay that way for up to 30 days, Department of Transportation Services Director Mike Formby said Thursday.

The site is secured by the Department of Emergency Services with a 15-foot-tall barbed-wire fence. However, Formby said, city officials say vandals likely accessed the site from the freeway above, where they severed PVC plastic conduits.

Those responsible also cut through iron conduits below, which would have required a power tool, Formby said.

"They went through metal. I don’t know what’s next," Formby said, adding that he has instructed DTS engineers to look into better ways to protect the lines.

Officials found segments of cable coiled and taped on the ground — likely discarded when the vandals realized they didn’t have copper, Formby said, adding that he has asked the Hono­lulu Police Department to try to lift fingerprints from the materials.

It will cost at least $10,000 to fix the damage, officials say.

Similar acts of vandalism at the H-1 site and another location, under the Middle Street bridge at Kame­ha­meha Highway, were discovered Nov. 4, knocking out 46 cameras across Oahu. Those cameras were restored five days after the damage was discovered, Formby said.