Originally Posted by
MinnMan
Missing the point. A thin veneer of moisture is already on the road. The H2O doesn't necessarily come from the exhaust.
Not sure if that is directed towards me or not. I agree that the thin veneer of moisture is already on the road. The road looks wet but people seem to assume that it is only water. Thus they are surprised when they discover physical chemistry. The water
doesn’t come from exhaust. There’s simply not enough water in the exhaust…and the air mixed with the exhaust from the car moving through the air…for it to cause icing problems at intersections or on the open road.
The water on the road (which looks wet but Surprise! Surprise! Surprise! it’s ice!) comes from some atmospheric event. Either snow that has melted or drizzle that has frozen or rain that has frozen. Those atmospheric events may pull the water from the exhaust down with them but the contribution from that water of combustion is insignificant to the formation of “black ice”.
And sorry, Denver isn't really that cold. Your average low temperature in January is warmer than our average high:
Denver: January average high-temperature 40.5°F, average low-temperature is 21.6°F."
Minneapolis January average high temperature 20.3 °F, average low temperature 7.5 *
Now you are missing the point. No, we aren’t as cold as Minneapolis but we have wider fluctuations and we
do experience cold weather on occasion. We get 60°F days here but we also get subzero days…often from one day to the next. We can even experience 60°F swings within a few hours. We likely have greater experience with melt water refreezing than you do further north.
On the other hand are you going to do the same analysis on everyone else posting here? Boston? 37°/22°F. So does Rumrunner6 not now what cold weather is? That’s a very similar temperature range to Denver’s.
How about sweeks in Chicago? 31/18°F. Or Grain Brain in central Iowa? (Des Moines) 30/13°F. Both are warmer than you experience but I doubt anyone would say they don’t know what cold weather is.