For taking long walks on ice and packed snow, nothing works better for me then screwing sheet metal screws in to my shoes. I get the kind with the hex nut head, 3/8 inch long for the toe and 1/2 inch long for the back of the shoe. For complete instructions visit http://www.skyrunner.com/screwshoe.htm. I don’t have a hex nut attachment for my cordless drill so I used my screwdriver’s hex nut driver and did it by hand. The screw driver is called a 6 way all in one screwdriver.
Last year I went through 2 pairs of Yak-Traks: they broke after about 2 weeks of use. Then I tried a pair of light weight instep crampons but they were always slipping up and I had to stop and adjust them all the time. Then I learned about the screw shoe. When spring came I just took out the screws and my running shoes where fine.
NOTE: Change into screw less shoes before walking on nice floors.