Yes your right it is 32 degrees that water freezes i think we all now that. But 37 degrees is a safe air temp slected because usually wind chill and ground temps are lower than air temp.

My two cents. I like the feature. It calls my attention to a possible road hazzard, and I thank the engineers for including it. What I am less happy about is the 'fasten seatbelt' noise. All right...if I do not fasten MY seatbelt, the reminder is enforcing safety, regardless of my preferences. But...the warning goes off when I have my briefcase on the seat next to me. Must be a weight sensor, set to some irrational weight, like 4 pounds!

Additionally, due to updrafts in bridges and overpasses, they freeze over faster.

Exactly. Said another way, if the temperature was falling, you wouldn't need to worry about ice forming until closer to 32 F, theoretically. If the temperature is rising through 32 F, they are assuming that the ice will not all be gone until the air temperature is 37 F. I suspect a corporate liability lawyer had an opinion about what temperature to set it at as well.

Used to use the same feature on a 1972 Rover 3500 S that I drove occasionally.

Wind chill creates an apparent temperature, not a real one. It applies to animate objects such as people who can sense the rate of heat loss, not roads. :)

As I've mentioned in previous posts, I added a switch to turn off the warning bell which I found to be just plain annoying!

You don't think roads are people too?
You are so insensitive.

I bet you put cookies in the oven to bake as well... disgusting.. ;)