Information AboutMultiplex (road) |
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A concurrency, '''overlap''' or '''coincidence''' State Highway Routes Selected Information, 1994 with 1995 Revisions ( PDF ) - see Route 3 for instance on a road network occurs where a single physical road carries two or more different Highway , Motorway , or other Road Number s. '''Multiplex''' is a Neologism , albeit well-used, used by Roadgeek s for this concept, as an extension of Other Meanings Of The Term . The practice is relatively common; where two roads must pass through a single geological feature, or crowded city streets, it is advantageous for road designers to merely divert them down the same road, saving on the cost of a new road. UNITED STATES In the United States , highways often form concurrencies in rural areas. As highways in the U.S. are signed with a Cardinal Direction , it is possible for two highways signed with opposite directions to be running along the same piece of road; a " Wrong-way Concurrency ". Most of the time, concurrencies are simply marked by placing signs for both routes on the same post; occasionally a state will instead sign the road as "to" the less major route. Several states don't officially have any concurrencies, instead officially ending routes on each side of one. In these states, concurrencies are typically poorly signed. In the mid- 20th Century , California had numerous concurrencies, but the California Legislature removed most concurrencies in a comprehensive reform of highway numbering in 1964 . / AR-43 at MO-43 near Southwest City , Missouri ]] A particularly unusual concurrency occurs along the Oklahoma / Arkansas state line. At the northern end of this border Oklahoma State Highway 20 concurs with Arkansas State Highway 43 and the two roads run north/south on the boundary. In its northernmost mile, the highway curves to the west, at which point OK-20/AR-43 is entirely within the State of Oklahoma. At least two roads run concurrently with their opposite direction. A short stretch of Broadway in Pawtucket, Rhode Island carries both directions of Route 114 , and a short stretch of northbound Interstate 279 , as well as the ramps leading to it, in Pittsburgh, Pennsylvania carries both directions of Truck U.S. Route 19 . UNITED KINGDOM In the United Kingdom , it is common for major through routes to run concurrently with others. Only one road number (typically that of the more heavily used route) is ever shown on road signs however; the other road is either bracketed on the sign, implying that the major route leads to a junction with the minor route (which it will do at the end of the concurrency), or left off altogether. For example, the A82 concurs with the A85 for five miles in western Scotland . Each route-confirmation sign-header gives the road number as "A82 (A85)". The A449 and A40 concur from Raglan to Ross-on-Wye , some fifteen miles straddling the Welsh-English border at Monmouth , is actually well double-signposted, but is confusing in road atlases, where only "A40" is shown, yet it is the B12(A) that is a dual carriageway link between the M4 and M50 motorways. REFERENCES |
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