That makes perfect sense, but I’d never before thought to wonder about how tailpipe condensate (tailpee?) acts in cold weather.
TIL: car exhaust has found yet another way to kill everybody.
Thanks, Maggie. I find your Winter tidbits fascinating.
The slick ice at traffic light intersections is due to the melt/refreeze heat coming off the exhaust systems of the vehicles waiting for the light to change.
The catalytic convertors get really hot.
Thanks, tree huggers! |-{)
I’m genuinely surprised that you only learned this today. IIRC, it was a normal bit of information from driver’s ed (in Minnesota). Guess it wasn’t part of the curriculum in Kansas?
Related unintended consequence - energy saving LED traffic lights freeze up because they don’t generate enough waste heat.
http://sweetness-light.com/archive/energy-saving-stoplights-freeze-over#.UuFJSnnTm6o
Hm. And I thought Black Ice came from computer viruses. You know, like in William Gibson? 
Out in the boonies the black ice spots seemed to be locations that got a decent amount of sun, but had a steady wind blowing across an open field – an imperceptible glaze seems to form in those spots.
There’s a reason it has a tendency to form at stop lights.
Probably depends on geography. I had no idea what black ice was supposed to be when I learned to drive up in Alaska, because from October to April every single road is a polished sheet of ice. It doesn’t matter if some of it is black, because it’s all slippery.
It wasn’t until I moved south that I got the context, it’s literally just ice that you can’t see because it blends in with the asphalt.
Black ice, dangerous and sneaky.
So any word on what causes brown acid?
Thanks for that link. I see it was from back in 2009, but it was interesting. The law of unintended consequences strikes again. What I found particularly entertaining was the level of vitriol in the comments. It seems that those commenter came in two flavors. Those to whom this is proof that anything “green” is the devil and those who’s mind are so green-washed that they deny that this is a problem and deflect any criticism with petty personal attacks. They pay no credence to the fact that new technologies come with unforeseen pitfalls to overcome. In areas where this is a problem just add a defroster to the lights similar to ones found on a cars rear windows or outside mirrors that turns on only when conditions warrant it.
Everybody in Finland (that whatched tv in 1977) knows that black ice is caused by evil man painting the roads with the stuff.
Black ice didn’t land on the road. The road landed on black ice!
So, does this mean that (eventual) large scale vehicle electrification could significantly reduce black ice formation?
Maybe we should start calling it “NSA ice”?
What’s the chance Dick Cheney has relatives in Finland?
I’ve also heard the term “Black Ice” used by street racing enthusiasts to refer to rain-slick pavement, comparing the lack of traction on the dark “black” wet sections of pavement to driving over ice.
