Skidding on Ice

I take a two mile walk every morning, rain, snow, ice or shine. I wore
out my pair of walking shoes, so I decided to go whole hog and buy an
expensive pair. I stated to the shoe salesman that I wanted something
like the ones I had worn out so I could walk on icy sidewalks and the
like. He assured me that the pair he sold me would be good for that.
So, yesterday, after winding up on all fours for the fifth time, I
decided to return my shoes. Well, the store policy is you can return
them within 14 days if they had not been worn. Hmmm, you can take a car
for a test drive, can't you?
I convinced another salesman to replace my shoes. He did a little
talking with someone in the back room and said the following. The shoes
that I had returned had a one piece polyurethane sole/heel. The
replacement ones had a one piece "rubber" sole/heel. It felt softer to
my calibrated fingernail. I had shoes in the past with a crepe sole/heel
which did perform well on ice. Of course, they wore out rapidly on
cement.
My question is, shouldn't there be a standard way of rating shoes for
grip on various surfaces? I can understand why the stores don't want
shoes returned after use. But there should be some kind of "test drive,"
if you will, or standard for walking shoes. What materials are best for
differing conditions?
Has anyone any opinions on the subject? Any good advice in how to pick
shoes of this nature? After all, salesman assured me these would be good
for my purposes. And I took his word as I and my wife had been shopping
at that shoe store for years and have always been satisfied. In fact I
am still satisfied as I was able to return the shoes despite "store
policy."
Al