Saturday we fished Marion in Lakeville. 12″ of ice was quite normal in the boat launch area. I know in other locations on the the lake it is usually thinner, so caution is still needed.
I did see several brave souls driving on the lake in the same area. I think it might have to be slightly thicker for me to have confidence in the ice that not that long ago was greeted with 40 temps and lots of rain.
Take care – be safe.