In the latest in a series of vexing copper heists, thieves over the weekend dug up copper wire worth about $85,000 that connected 16 lights on the H-1 Freeway, state officials and police said.

The suspects unearthed 14,000 feet of underground coils and chopped it up before removing it, police said. Workers with the state Department of Transportation found the plastic tubing that covers the coils — which are made up of six strands of No. 2 copper wire — strewn along the roadside, police said.

Ten other lights were broken into but the wires were not removed.

The thieves hit lights along the H-1 Freeway from Makakilo to Kunia that already was dark because of thefts this summer.

In the past four months, copper thieves have stolen wire and caused a total of $208,000 in damage on state roadways, and crews are still working to restore lights on the Leeward stretch of H-1 Freeway and on the H-2 heading into Mililani.

Police have at least five felony investigations open in connection with the thefts, but say it is difficult to apprehend the thieves, who may be donning orange vests and hardhats and disguising themselves as state DOT employees or working at night along stretches of road already dark from previous thefts.

"These guys are really taking money from everybody at this point. They are taking taxpayer money from everybody," said Scott Ishikawa, spokesman for the state DOT. "We're asking for the public's help."

Police have opened an investigation of first-degree theft and first-degree criminal property damage. DOT workers estimated the value of the wire at $85,000, with the labor pushing the crime's price tag well past $100,000.

Some Leeward Coast residents have adjusted their driving habits around the dark stretches.

Frank D. Slocum, who lives in Wai'anae, tries not to drive past Makakilo at night so he can avoid speeders and the unlit sections.

"The whole (dark) stretch of freeway is a problem," he said. "I think everybody realizes it is a problem but no one has an answer. You've got to put on the lights so you can see at night."

STILL IN THE DARK

In August, thieves stole more than $8,000 worth of copper wire from a box under the Makakilo overpass, plunging H-1 from Makakilo to Kunia into darkness in both the east- and west-bound lanes. The thieves made off with 250 feet of copper wire, breaking the electric circuit and disabling a stretch of lights.

More than 50 lights remain out on the H-2 from the H-1 interchange through Mililani.

No arrests have been made.

The Department of Transportation is researching a way to secure the copper wire from thieves in a way that won't hinder workers trying to restore lights in an emergency.

Officials said thieves apparently dig up the wire in the day, when the electric current is off.

The wires are buried underground or mounted in plastic pipes lashed to the side of jersey barriers or beneath bridges. Circuit boxes, like the ones ripped off beneath the Makakilo overpass in August, contain conduits wrapped with copper wire.

Contractors replaced the copper wire along H-2 twice but stopped after they realized the thieves were continuing to strike, DOT said.

The state buys copper wire for about $3,500 a spool, but it is exploring the possibility of using aluminum wire, which is less expensive than copper. Aluminum retails about 68 cents a pound, according to the state.

Thefts of aluminum from the side of bridges have been reported this year but are not on the same level as copper thefts, police and state officials said. Copper sells for $3.44 a pound, according to the Web site www.metalprices.com, which tracks world metal markets. The price has increased almost 200 percent in the past year.

Copper thieves are encouraged by the abundance of copper in accessible locations on O'ahu and the metal's resale value. Most copper sources are not adequately guarded and people may not recognize what they're witnessing if they come across a copper theft, police said.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.