Whats the difference between highways and freeways/the interstate in the US?
There are a lot of overlapping terms out there meaning more or less the same thing. A freeway is a more precise technical term whereas a highway is more generic. For the best definition of Freeway let’s see what the AASHTO Policy on Geometric Design has to say. Freeway – The highest type of arterial highway is the freeway, which is defined as an expressway with full control of access. (Basically this means that the federal or state governments have jurisdiction over the access points of the roadway for safety considerations.) Essential freeway elements include medians, grade separations at cross streets, ramp connections for entrance to and exit from the through pavements, and (in some cases) frontage roads. From the Highway Capacity Manual, Transportation Research Board: Highway – …with no control or partial control of access..may have periodic interruptions to flow at signalized intersections… So the main difference between Freeways and Highways is that of access and signalizatio
eritain: Interstate 5 and California 99 are often thirty miles apart or more – 5 runs up the west, Coast Ranges side of the Central Valley, while 99 runs up the east, Sierra side. The last bits of 5 weren’t built until the late 1960s. Here‘s a ridiculously detailed account I was reading yesterday.
Master’s in Urban Planning here. eritain has the correct answer. The West and Southwest have fewer highways and more Interstates. Another comparison: Interstates did not begin to be built until the 1950s, by definition. Highways have been built since cars became popular, and before that, they were usually horse paths. This site provides a simple guide to deciphering the whole numbers/letters thing, and also discusses the vernacular of “highway” vs. “interstate” etc.
mdonley, I’m guessing eritain is in Washington, where I-5 and SR (former US) 99 are generally no more than a couple of miles apart. In many places I-5 actually follows a former alignment of US 99 (though 99 had multiple routes itself over the years), so you can’t drive the “old highway” without taking the Interstate. I too grew up in the West (well, the Pacific Northwest, anyway) and have always known a distinction between highways and Interstates, though both can be “freeways.” A lot of the older highways, though they technically are usually called SR (State Routes), or are US highways, are called “highway X” in informal usage: “Highway 99” or “Highway 2”, for example. But one would generally not call the Interstate highway “Highway 5” — it’s invariably “I-5” to locals. Anyway, to me a highway is an actual signed and numbered route where at least a certain level of speed is allowed. 🙂 So here that’s SRs and US Highways, usually. If it’s a limited access road, that’s a freeway, usual
Oh, and I should have mentioned that in large swaths of the west, the reason you can’t really take anything but an Interstate between cities is because the old roads are largely where the Interstate is now. Farther east, the Interstates were usually built along new right of way, or much more so than out west.
