For the most part, it's also called US Rte 1. It's Rte. 1 in parts of NYC , too, and in much of New Jersey. It's a road that connects and continues across state boundaries. But, no, it's not the oldest road in US. We east coasters cling to our history, (the Mayflower, the 13 original colonies and such) but there are west coast road from the Spanish colonial days that are just as old and older.
I only know (and then only know a very few) of some of the older road, like the Boston Post Road.
Broadway is an other one--(Rte 9 in most of the state.) This land mark road is build on (for the most part) an Indian trail—It's one of the few streets that isn't part of NYC famous Grid System—since the road was a well established one, long before the grid came into place.
Every read The Last of the Mohican's? The path through the forest, is for the most part, is Broadway/Rte 9. There are still to be found, landmarks (caves and glacial erratic boulders) mentioned in the book that still exist (one cave is in Inwood Park, in norther Manhattan).
Some of these old roads are crooked, some make right angle turns (Glebe Avenue in the Bronx for example) which marks the borders of St Peter's Church (Anglican) old glebe; and Minetta Lane in, down in Greenwich Village, is another example—it follows the twisting path of an old stream bed.
After WWII, was the old colonial roads and cow paths high ways were, replaced by the new interstate system. Sometimes the new highways were superimposed on or paralleled these old roads. Parts of I-80 in the mid west run parallel to the Oregon trail!
Do you know the logic behind the Interstate Highway System? First they are I-roads. One set (ending in 5's (5, 15, 25...95) run north and south.
I-5 (from souther CA to Washington state –and a Canada build a spur connecting I-5 to the Canadian highway system) on the west coast, a bunch of others, (I-15, 25, ...) till finally, I-95 (Florida to Maine (mostly!)) on the east coast.
I-roads that end in Zeros (10 in the south, and 20, 30...90(north) are East/West roads.
These 2 sets of roads are the major arteries. (There is one near you!)
And then, there are the spurs and ring. These, too, have a logic. Ring roads (DC's belt way is the best example) are road that ring major cities. These have 2,4,(and maybe 6 and 8 designations)
Depending on how far they are from the city they ring. All up and down I-95 are I-295 and I-495's rings. Few are as round and complete as DC's Beltway—The perfect ring road!
In the NYC area, I-495 in NJ is sort of C shaped and broken up. It skips over Manhattan, and it continues onto Long Island!
There are all sorts of spurs, too, to these major roads--(to cities north & south, and east & west) and there is some sort of logic to these spurs, too, (but since I am less familiar with them, I haven't fully worked out the logic, or the numeric codes associated. (feel free to chime in!)
Though basically they too follow the same numbering logic.
One example is the Pennsylvania Turnpike(I-76) —build before the Interstate System got started, it “joined' the interstate system. But it, like the NYS Thru-Way, are older roads were, and still are, toll roads –-Some old roads were private, some regional and some state build—and these often had tolls--and tollhouse's (as in the cookie) or gates (and turn pikes to prevent access/progress until the toll for their use was paid.
Most of these roads now have I- numbers that follow the same logic of the Big I-'s—Odd numbers (I-91 for example) are north south roads, and even numbers I-76 (Pennsy Pike) are east/west routes. Many of these roads (well the east coast ones) are new enough that I remember them being built!
In Queens, remnants of some intermediate roads exist—these are newer than colonial roads—but predate most modern roads. Like the Vanderbilt Highway—an early example of a modern highway!--Much of the road is elevated on berms, and major crossroads are spanned with overpasses. This road is now to be found in parks, (as bike paths) but further east, local governments have taken over the road, and maintained, improved or extended this once private roadway. I don't know of other private highways--abandoned or still in use. But I bet they existed in many east coast cities.
On the east coast (and Chicago, too, for one) there are a bunch of state roads that date from WPA projects. - Many of which are designated as parkways. Elegant, curving (many have been “improved” over the years, with the worst of the curves removed) roads, with broad parks either side.