History of interstates
| Dwight D. Eisenhower National System of Interstate and Defense Highways | |
|---|---|
.svg) .svg) Highway shield for Interstate 215 and Interstate 15E | |
 Interstate Highways in the 48 contiguous states | |
| System information | |
| Formed | June 29, 1956[1] |
| Highway names | |
| Interstates | Interstate X (I-X) |
| System links | |
The auxiliary Interstate Highways (also called three-digit Interstate Highways) are a supplemental subset of the freewayswithin the Interstate Highway System of the United States. Similar to the mainline Interstate Highways, these highways also meet all Interstate Highway Standards, they receive the same percentage of federal funding (90%), and they comply with other federal standards.
Auxiliary routes are generally given as spur routes (which connect to the Main route at one end), bypasses (which connect to the Main route at both ends), or beltways, which form a complete circle intersecting the main route at two places. There are some routes which connect to the parent route at one end, but connect to another route at the other end; some states treat these as spurs while others treat these as bypasses.
These shorter auxiliary routes branch off of main routes and are numbered based on the number of the parent route, such that all I-x95 routes are supplemental routes for I-95. While some exceptions do exist, generally spur routes are numbered with an odd hundreds digit (such as I-395), while bypasses and beltways are numbered with an even hundreds digit (such as I-695). Because longer interstates may have many such supplemental routes, the numbers may repeat in each state along their route, but they will not repeat within a state.
The auxiliary Interstate Highways were once singed as Suffixed Interstate highways for example Interstate 215 (I-215) was once singed as singed as Interstate 15E (I-15E) because its parent Main interstates highway is Interstate 15 (I-15)
Terminology and guidelines[edit]
Routes that begin with an even number generally connect to the main highway in two locations, while odd numbers only connect in one location. The basic tenets of the auxiliary Interstates are divided into three branches: spur, loop, and bypass routes. Each one signifies a different characteristic of the auxiliary route.
The first digit of the three digits usually determines whether a route is a bypass, spur, or beltway. The last two digits are derived from the main Interstate Highway. For instance, I-515 contains an odd number in the first digit (5), and this indicates that this freeway is a spur. The last two digits signify the highway's origin. In this case, the "15" in I-515 shows that it is a supplement to I-15.
Numerous exceptions to the standard numbering guidelines exist in many places. This can be for a number of reasons. In some cases, original routes were changed, extended, or abandoned, leaving discrepancies in the system. In other cases, it may not be possible to use the proper number because there are none available, causing a "non-standard" number to be used.
History of Interstates[edit]
Most Auxiliary Interstate Routes (3-digit Interstate Routes) have a history. This history could be that they were once signed with directional suffixes or were U.S Highways and/or State highways. Example I-215 is a bypass for I-15, and from SR 60, it was signed as SR 215; the rest was I-215. Eventually, in 1994, it was upgraded, with all of it being I-215. Before that, I-215 was signed as I-15E. This History is From Mainly (3-digit Interstate Routes) that have even numbers which are bypasses to serve a Metropolis. Another example is that I-35 Splits into I-35E,and I-35W to serve the Dallas/Fort Worth Metropolis in Texas. Many Auxiliary Interstate Routes
References[edit]
- ↑ Weingroff, Richard F. (Summer 1996). "Federal-Aid Highway Act of 1956, Creating the Interstate System". Public Roads. Washington, DC: Federal Highway Administration. 60 (1). Retrieved March 16, 2012.
This article "History of interstates" is from Wikipedia. The list of its authors can be seen in its historical. Articles copied from Draft Namespace on Wikipedia could be seen on the Draft Namespace of Wikipedia and not main one.
