When traveling, why does the road ahead look wet - but when you get to it, it is obviously dry?

What you're seeing is commonly known as a mirage. Merriam-Webster Online Dictionary has this definition for a mirage...

Main Entry: mi·rage

Pronunciation: m&-'räzh

Function: noun

Etymology: French, from mirer to look at, from Latin mirari

1 : an optical effect that is sometimes seen at sea, in the desert, or over a hot pavement, that may have the appearance of a pool of water or a mirror in which distant objects are seen inverted, and that is caused by the bending or reflection of rays of light by a layer of heated air of varying density

2 : something illusory and unattainable like a mirage

For More Information on "mirage" go to Britannica.com

What you are seeing is water vapor coming off of the hot road. This only happens on hot days, right?

Water is heated (not a puddle...just the overall moisture in the road) and comes up in wavey lines off of the road. That vaper then acts like a mirror, reflecting the sky and sunlight to you. This makes it look like the road is wet. The closer you get, the more the angle changes, and the vaper effect goes away.

not one of the above. you would be able to bypass them if the middle line isn't sturdy and there is not any oncoming site visitors, different than in a no passing zone. additionally, if mentioned vehicle is vacationing on the value decrease, take the hint and don't bypass. confident, staying power is a factor of it yet not the whole answer. EMT

It is the sun warming up the oils in the pavement. Also there are times that it is wet.

Optical illusion, eyes playing tricks on you!!! Heat rising off of pavement? ~:)

yes, it's called a mirage and in my state (az) during the summer i see it all the time. it's a pretty cool illusion.

i guess you are talking about heat waves maybe?