Question for the audience

If you drive in the Twin Cities, have you noticed that a lot of the overhead lighting on the expressways seems to be turned off at night? I have noticed that all the lights on the 35W bridge over the Minnesota River aren't being turned on -- I've seen this during my morning commute and noticed it as we were coming home last night. I also noticed that on various stretches of 35W elsewhere in town, it seems as though only half the overhead lights are in operation. This seems like a dangerous idea and I haven't seen any public discussion of the topic. Anyone have any idea why this change has taken place?