SAN JOSE (CBS/AP) — Motorists are quick to blame solo drivers, out-of-sync traffic lights and an improving economy for San Francisco Bay area traffic gridlock.

But copper thieves are a hidden culprit in the commuting mess.

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They tear out copper wiring powering metering lights, traffic signals and freeway electronic signs.

59 meters have been vandalized in the bay area in the past year.

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The California Department of Transportation has replaced wiring for 18 of those meters at a typical cost of $35,000 each.

And it can take up to four months to make repairs.

Copper can fetch up to $4 a pound at recycling facilities.

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