If you live in an area where it snows you know all about slippery sidewalks, porches, and driveways.  I mix a bag of clay cat litter with either rock salt or regular table salt and then sprinkle it on everything.  The litter will give you traction and the salt will help to melt the ice.  It's inexpensive and environmentally friendly if you use table salt.  the salt will also help to kill fleas and other pests in the summer.  It's especially good if you can't shovel because of ice.  The cat litter will help you in walking or driving on slippery surfaces.  Keep a bag of cat litter in your car and sprinkle it under the tires to help you if you get stuck.