black ice can easily take down even the most skilled of cyclists.

the only way to obtain some black ice insurance is to buy a set of studded tires.

they're not infallible, but they will give you a FAR larger margin of control on black ice than a conventional tire.

for icy plowed streets i highly recommend the schwalbe marathon winter. they're not the best snow tires around, but they will chew ice up and spit it out with their 240 studs.