Some U.S. Highway 95 commuters have been literally left in the dark after copper thieves disabled scores of lights along the freeway in the southern Las Vegas Valley over the past few months.

The thefts of copper wiring from U.S. 95 light poles, done piecemeal over the past year, have crippled most lights between Charleston Boulevard and Sunset Road and will cost taxpayers around $500,000 to repair.

"One day, they see the whole string of lights on. The next day, it's off," Tim Robinson, a supervising electrician with the Nevada Department of Transportation, said Friday. "It's real dark from Charleston all the way to Sunset."

The thefts appear to be part of a widespread crime spree targeting copper that in the past has knocked out electricity and telephone service to parts of Southern Nevada, shut down a radio station in Canada and even sparked a house explosion in the Midwest.

The thefts have coincided with a surge in the value of the precious metal.

"Somebody's just getting in there and stealing the copper," Robinson said. "It's hurting us pretty bad. It's still going on to this day."

Authorities believe thieves dressed in outfits similar to that of road workers to access areas where engineers are building sound walls along U.S. 95, also known in that stretch as Interstate 515.

In areas that nearby residents would expect to see workers, thieves have yanked out as much as 200 yards of copper wiring at a time from a single light pole.

Some electrical boxes are behind sound walls, shielding thieves from the eyes of passing drivers.

Authorities did not say how many light poles have been crippled, but said most lights have been targeted in the area in question.

Bob McKenzie, a highway department spokesman, said the lack of lighting does not make it more dangerous to drive that stretch of freeway, which carried as many as 130,000 cars and trucks each day in 2005, according to state statistics.

"The public, they rely on us having these lights operable," Robinson said. "It's not too much of a hazard (for drivers). It's an inconvenience."

McKenzie said the $500,000 cost for replacing the copper in lights along U.S. 95 includes less than $150,000 to buy new wiring.

"The majority of the cost goes to repairing and replacing the damage" caused by the thieves, McKenzie said.

Copper wiring also was reported stolen late last year from numerous Interstate 15 light poles near the northern Las Vegas Beltway, Robinson said.

Other municipalities and private developers in Southern Nevada and across the country report a rash of similar thefts from construction sites and utility boxes.

Earlier this year, Clark County public works officials reported more than 100 cases of copper wiring being yanked from street lights, resulting in darkened streets and a months-long backlog of repair work.

In September 2006, thieves pulled down more than 1,000 feet of copper cable near Boulder City, cutting off long-distance telephone and high-speed Internet service for that community for several days.

"It's really rampant across the country," Steve Moyer, security chief for Nevada Power parent company Sierra Pacific Resources, said last year.

In January, copper thieves stealing wire from an electrical substation near Pahrump cut power to customers in Sandy Valley and Mountain Springs for up to seven hours, according to the Pahrump Valley Times.

Just this week, a Canadian radio station was knocked off the air after thieves stole copper wiring from the station's transmission tower, the Vancouver Sun reported.

And in 2006, thieves stealing copper pipes in Peoria, Ill., triggered a natural gas explosion that demolished a house, the Peoria Journal Star reported. No one was hurt.

"It's a continuing problem, regardless of where you are," McKenzie said.

In recent years, demand has skyrocketed for copper, a key metal used for wiring and plumbing. That has pushed prices upward.

Copper traded for around 75 cents a pound until mid-2003. Prices steadily grew to around $4 a pound by mid-2006. It has been trading for around $3 a pound recently, according to metalspotprice.com.

The theft of metals for resale "depends on what the popular metal of the month is," McKenzie said.

In Washington and Oregon, highway guard rails being stolen and sold as scrap metal, he said.

Robinson and McKenzie said the highway department has taken action in hopes of preventing future thefts, but they wouldn't detail the new security procedures.

Both men ask members of the public to report suspicious activity around sound walls, light poles or construction sites by calling police at the nonemergency 311 number.