Science Fair Project Encyclopedia
An expressway is a divided highway, usually 4 lanes or wider in size, where direct access to adjacent properties has been eliminated. However, beyond those basic requirements, the specific meaning of expressway depends upon the state, province, or country.
Some places treat "expressway" as synonymous with "freeway", meaning that an expressway is fully grade-separated from all intersecting roads and traffic smoothly enters by merging from on-ramps, and exits only through steering onto off-ramps.
Other places, like California, draw a strong legal distinction between freeways and expressways. Section 257 of the California Streets and Highway Code is as follows:
- For the purpose of this article only, and to distinguish between the terms "freeway" and "expressway," the word "freeway" shall mean a divided arterial highway for through traffic with full control of access and with grade separations at intersections, while the word "expressway" shall mean an arterial highway for through traffic which may have partial control of access, but which may or may not be divided or have grade separations at intersections.
The point of this passage is that California expressways can have at-grade intersections (which may not always have traffic lights), which are obviously much more dangerous. See the article on freeways for more information about the subtle distinctions between freeways and expressways.
The vast majority of expressways in either sense are built by state or provincial governments, or by private companies which then operate them as toll roads pursuant to a license from the government.
The most famous exception to the above rule is Santa Clara County in California, which deliberately built its own expressway system in the 1960s to supplement the freeway system then planned by Caltrans. Although there were some plans to upgrade the county expressways into full-fledged freeways, those became politically infeasible after the rise of the tax revolt movement in the mid-1970s.
- Expressways of China
- Expressways of Japan
- Expressways of Singapore
- RIRO expressway
- Malaysian expressway system
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