DETROIT (WWJ/AP) - The Michigan Department of Transportation says one-fifth of the lights along freeways in Metro Detroit aren’t working — and copper thieves are mainly to blame.

MDOT spokesman Rob Morosi said roughly 20 percent of the lights on poles and beneath overpasses on freeways in Wayne, Oakland, Macomb and St. Clair counties are dark.

“We are responsible for about 5,500 light poles and also about 5,000 individual lights that are installed beneath overpasses,” Morosi told The Detroit News. “Right now we’re estimating 1,100 outages to those poles for a number of reasons.”

The main reason for many of the outages, according to Morosi, is copper thieves – who are stripping metal from the transformer cabinets.

“It’s not like the copper thieves are running out onto the freeway and stealing copper from the poles to sell at scrap yards,” Morosi said. “Instead they are attacking the transformer cabinets, many of which are actually located on the service drives.”

MDOT has identified the area around I-94, east of I-75, as one of the worst hit by thieves.

“We are taking measures to try to keep the cabinets safe and secure, but for every move we make, the thieves come up with a counter-move,” said Morosi.