WARNING: If your shoe has the words GEL or AIR in their name, be VERY careful where you place the screws.
I've inserted a number of hex head metal screws in the sole of my shoes. I tried them on the sidewalk in front of my house (well, my neighbour's since MY sidewalk is scraped clean!) and traction was vastly improved. Running on regular surface was a bit noisy but seemed to be fine.
So tomorrow morning, if the race officials tell us that there is ice on the course, I will wear my studded shoes.