Although each term applies often directly to the same thing, there are some distinct differences between a road and a street. It often appears that there is no purpose behind the plethora of titles and names given to pathways, but there kind of is. Perhaps some of you journalist Nazis are interested. Roads have destinations and streets are paved.
“A road usually runs between two more distant points, such as between two towns. A street is described as being a paved road or highway - in a city, town, or village, especially one lined with houses, shops, or other buildings. The implication is that if a street does not have these things, it will probably be called a road.” (Dictionary)
Roads can be turned into streets when a town expands, but because road is the more general term it can be applied to a street. Thus street is a narrower term under the road category, and is urban in principle or application. “The word “street” is sometimes used colloquially as a synonym for “road,” but city residents and urban planners draw a crucial distinction: a road's main function is transportation, while streets facilitate public interaction. Examples of streets include pedestrian streets, alleys, and center-city streets too crowded for road vehicles to pass. Conversely, highways and motorways are types of roads, but few would refer to them as streets.” (Wikipedia)
For language differences I highly suggest you check out the Pronunciation of the names of thoroughfares node. It goes over where the accent or stress is put in the phrase. Normally two word thoroughfares are stressed in the second word, see the node for a list. The exception is street, instead the first word is stressed, ie. Wall Street.
One of the most interesting thoughts when it comes to diversifying the two terms is the pedestrian. With the descriptions already given in mind, you can imagine most paths in a city are called streets. Expanding upon this you can ask yourself, “Would a street performer or a beggar be on a street with high pedestrian activity or on a road in the middle of the desert between Las Vegas and Salt Lake City?” Well of course the question is rhetorical, but the point is clear. Roads connect cities, towns, and states. Streets connect people. Phrases such as, “Hit the road,” express a desire for travel. Or in Ray Charles's case, a good case of (get your act together) freezing water in the face. This musical and societal saying only supports the difference.
In an attempt at a system Manhattan divulged the following:
North-south are avenues
East-west are streets
There is no national standard on what to call streets and what to call roads, or anything for that matter. In fact another place in the country has the opposite standard.
Guilford County, North Carolina, prefers:
North-south are streets
East-west are avenues (take that, Manhattan)
That’s just a specific example to show how the system can even seemingly contradict itself. But what keeps this chaotic system under control? The U.S. Postal Service. “The U.S. Postal Service, exhibiting rare common sense, has decided suffixes aren't worth worrying about. It merely requests that street names be unique without regard to suffix, lest mail carriers be confused if the suffix is left off. (A notorious violator of this principle is Chicago, which has numerous instances of streets with names like 21st Place running parallel to 21st Street.)” (Straight Dope) Okay, so maybe the U.S. Postal Service doesn’t actually control the system, but surely it does keep it from worsening.
In context a highway is longer than a freeway, a road is longer than a street, and an avenue is longer than a lane. Additionally if you want to go to hell you need to take the road to hell because their ain’t no street that goes there. Road to Perdition, a 2002 movie, Road to El Dorado, a cartoon-movie, are both examples of roads to places. Comparatively the Wall Street Journal connects people, oddly enough. The longest road in the world is possibly the Pan-American Highway, which starts in Alaska, and runs all the way down to the southern tip of South America, but is not technically completely connected. The Stroget in Copenhagen, Denmark, is billed as the world’s largest pedestrian street, lined with shops and cafes. (Yahoo)
”There is such a thing as a street sweeper, but there isn’t a big enough broom to sweep a road.” - (My attempt at creating a quote.)