Originally Posted by cyccommute

Again, it's not the car exhaust that causes the ice nor the intersections to be more slippery. There's just not enough water in the car exhaust at an intersection to cause the problem. If each car sat at the intersection and burn and entire gallon of gas, maybe, but that isn't what happens. A car burns around 0.1 gallons per hour idling. A car waiting for 2 minutes for a typical stoplight would burn 0.003 gallons or about 7g of gas. Through the magic of chemistry, I know that 9g of water is going to be produced per car. That's a minuscule amount of water.