Last night (Nov 23) we had the Seattle's Snowpocalypse of 2010. We needed a grocery run for our Thanksgiving holiday, and I, loving cold weather and ice as I do, decided to attempt a trip to the store on my cargobike.
This trip was on relatively flat ground, and only 2.2 miles roundtrip. I had a safety precaution to go slow enough that if I did lose control I could just put my feet on the ground and wrestle the bike to an upright stop.
Going there had some slippery moments. Didn't go down, but did feel the tires lose traction. Then I loaded the bike up with two gallons of milk, chicken, beer, etc, etc. $107 worth. By then I had a little experience from the ride over. The rest of the trip was a hoot(i.e. fun). The extra weight, plus driving in a higher gear (4th and 5th), worked to an advantage just like in cars. It took a certain amount of discipline -riding the bike with "ice driving rules"- but wow was it fun in a unique visceral sort of way.
Yet another way in which cargobikes do what no other bike does.