Virginia
Methods:
?????
Utah
Methods:
Clustering, sort of
Utah's state route numbering plan goes something like this: Prior to 1978, the allining of Route Numbers to Shield Numbers, or no Route Number Duplication, most of the teens were clustered in the southwest. There was: U-14, U-15, U-17, U-18, and U-19. U-14, U-17, and U-18 are still existing in the southwest; U-19 is a business loop in Green River, and U-15 is now U-9. I still consider that U-15 is still clustered in the Southwest Corner of the State; but there are 3 differences: Now, U-15 is a border-to-border route, and is now north-south, and is I-15. Also, Business Loops from Interstates are State Routes. There is: (All along I-15) St. George Blvd. (U-34), Main St. in Cedar City (U-130) (even though U-130 goes clear up to Minersville), U-271 and U-274 in Parowan, Main St. (U-160) in Beaver, U-99 in Fillmore, U-64 in Holden, U-41 in Nephi, U-126 in Ogden, and a few more north of there.
Virginia
Methods:
?????
All VA highways not maintained by municipalities or local governments are state highways. Generally, the lower the state highway number, the longer the route. Note how routes 3, 4, 5 and 6 traverse most of the state, and how many two-digit routes travel for 100-200 miles or more. Highways 100-199 generally only serve a few towns.
Many of the 3xx routes are access roads for prisons or state parks. You won't find them on RMcN-type atlases, but they are posted. Other 2xx and 3xx routes are short-distance through routes. There are some Virginia 2xx routes in clustered, somewhat sequential, patterns, e.g. 200 through 218 off of 3 in the Northern Neck. 4xx routes exist only in larger metropolitan areas. The highest 4xx route Matt Steffora knows of is 420.
This brings us to the peculiar 598. Virginia 598 is an old stretch of U.S. 52, which was rerouted when the East River Mountain Tunnel was built (the tunnel now carries 52 and I-77). 598 is only 3 or 4 miles long, and another 2 or 3 miles in West Virginia, and all the road does is ascend and descend East River Mountain between Exit 66 of I-77 and Bluefield, West Virginia. Now, the highest possible number for a primary-series state highway in Virginia is 599, but there's no 599 in Virginia, and there's no other road numbered between 420 and 598. We'd really like to know why the number 598 was chosen.
All the above ignores Interstate and U.S. highways, such as U.S. 322 and 460 and I-495, that fall outside these conventions.
Virginia is pretty good about maintaining numbers from other states as these roads pass into Virginia. Highway 16, in particular, continues into N.C. and W.V. with the same number.
Most Virginia counties have secondary routes in addition to the state routes. These start at 600 and go up seemingly forever. Virginia 9xxx secondary routes lead to elementary / middle / high schools, and these are often signed. The 600+ system is officially a "county road" system, but it's actually state maintained. Numbers can and do repeat between counties. Unincorporated towns may have "T" 1xxx numbers on all their streets. an "F" number indicates a frontage road.
Regular state routes can not go past 599. US routes probably can't either, there is no number above 522 and no new US routes are expected. Currently there is one Interstate above 600, I-664. VA probably wants to avoid having any more I-6xx's, though. It's not likely they would be needed, although I-895 is in the future. Simply, it makes more sense to have 895 instead of I-695 since very few counties reach the 800's in secondary numbers. Also, secondary numbers only have to be unique to its county, thus there are probably ten 611s.
Also, duplicate numbers between state and US roads is permitted, but there may only be one (13). There are no duplicates of interstates, other than 664.
WV state primary routes are signed inside a black square. In general, low numbered N/S routes are even and low numbered E/W routes are odd. Duplicate state and interstate numbers were prevalent until the mid-1970's, when renumbering for WV 64 and WV 77 were made. In many cases, state route numbers have been selected or changed to match routes in adjoining states.
WV secondary routes are signed inside a standard circle on a black square as whole numbers. Many of these routes are actually FAP primary. The numbering is made in each of West Va's 55 counties, so plenty of duplicate numbers exist. Sometimes, state or US routes have been downgraded to secondary route numbers (old US 21 is now WV 21 in Wood, Jackson and Kanawha counties). Recent oddities such as 3-digit SR's have been selected to match primary or secondary routes in adjoining states (Monongalia Co. WV 857 matches PA 857). They are mostly found in urban areas (in C.C. Slater's experience). These roads appear to be an urban link system. The two he's seen (in Morgantown and Martinsburg) fit that description.
WV minor secondary highways are "fractional". These use a circular shield, and generally have the highway they branch off of as the "numerator" and the actual road number as the "denominator": So
522
---
3
is the third highway branching off of US 522. Locals write these routes as SR-522/3 and say "522 over 3". Oddly enough, while few secondary routes have been upgraded to a new state route number, numerous minor secondaries have. The resulting numbers have been interesting. Jefferson Co. SR 23 became WV 230. Berkeley Co. SR 9/1 became WV 901. Kanawha Co. SR 5/1 became WV 501 at the same time that Kanawha SR 60/1 became WV 601. Perhaps the oddest WV route numbering was when Kanawha SR 35/2 became WV 622 in the early 1980s. This renumbering made sense because US 35 turned into WV 62 (and WV-17 turned into US-35) in early 1970s after the collapse of the Pt. Pleasant Silver Bridge into the Ohio River caused the bridge to be rebuilt south of the Kanawha. Note that WV 17 was reused for the section of old US 119 bypassed by Appalachian Corridor G. Other anomalies include some "73"/x roads in the Morgantown area. One is 73/5 that branches off US 119. These are left over from the time I-68 was WV 73.
Fractional signs always appear on a green sign with a road name.
Washington
Methods:
Geographical and Parent Route
The current system was first posted in 1964. The 1963 session of the state legislature authorized the Department of Highways (now DOT) to come up with a numbering system to replace the earlier system in place at the time. The old system included several branches of the primary system with the same number, duplication of numbers between state and US or Interstate routes, and an explicit numero-alphabetic system of secondary state highways. The old numbering scheme used somewhat of a hierarchical system. Primary State Highway (PSH) 1 headed north-south thru Seattle toward Portland, Oregon and Vancouver, British Columbia. PSH 2 linked Seattle and Spokane. PSH 3 made an arc thru south central and southeast Washington, passing thru Yakima, Pasco and Walla Walla.
The secondary state highway system was created in 1937. Secondary State Highways (SSHs) 1A, 1B, and 1C branched off of PSH 1. US and later Interstate routes were assigned PSH numbers for official purposes. These PSH numbers were not posted along these routes, however.
The new (1964) system eliminated duplications between State Route (SR), US and Interstate routes. Since Washington has a US 2, no other SR is now numbered 2, I-5 is now the only route in Washington numbered 5, etc. Duplicate SR numbers were eliminated. The explicit SSH system was eliminated. From 1964 to 1970, the old numbers remained as the official numbers. The new numbers were referred to as sign routes, or SRs. In 1970 the sign route numbers became the official numbers.
The layout of the new system is geographic. Like US and Interstate routes, even numbered SRs run E-W, odd N-S. The numbering system starts in the SW corner of the state. Most major routes have one or two digit numbers. Other routes are three digit. There is no formal system of primary or secondary, however. The three digit route numbers have the first digit or two digits of the number as the trunk or root number. SR 500, 501, and 502 branch off of I-5. SR 223,224, and 225 are linked with SR 22. Certain SR trunks are implied. The 150 series numbers branch off of US 97 between Wenatchee and the Canadian border, the 290 series off US 395 north of Spokane. These US highways are located where SRs 15 and 29 would be.
The 1964 system has evolved. Subsequent changes to
the US system have made adjustments necessary, e.g., the extension of US 12 into
Washington. Like in other states, portions of certain US routes became SRs with
the old US number, e.g. US 99 and SR 99. From time to time, routes have been
added to or dropped from the state highway system. The 1991 session of the
legislature passed a bill that took effect in 1992 swapping 300 miles of routes
between the state and local governments. Some of the highways that were picked
up by the state were given numbers that did not fit in with the 1964 numbering
scheme.
Each number will be assigned to only one highway. A state highway will not have the same number as an Interstate or US highway that goes through the state (e.g. there is no state highway 43, 90, 94, or 51, etc.). The only exception is State Road 39, which existed before the stretch of US 51 was renamed I-39 in 1996).
There are no one-digit state routes.
There seems to be no concrete numbering plan for state routes, except that three-digit roads are generally shorter.
County trunk highways are letters (I think Wisconsin and Missouri are the only states that have this). Most are single letters, some are double, near their parents (ie. PP branches off of P). There can also be weird combinations like MH. Most county trunks retain the same letter over county boundaries. There are also three letter CTHs (ie HHH in Grant County).
The Wisconsin equivalents of odd highways like US 52 and 62 are Highway 23, which runs west halfway across the state, then in the middle turns south to the Illinois border, and highway 73 which runs north then west and north again.
Wyoming
Methods:
Primary: Parent route and geographical; Secondary: By
county
In Wyoming, primary state routes are determined by
the corresponding US routes (ie, Wyo 130, 230, 430, and 530 all branch off US
30). Other routes, like Wyo. 28, are given based on where they should fit into
the US route grid. Wyo. 22 and 24 were too important to be secondary routes,
maybe. Secondary state routes are numbered based on a clustering system, where
the route's county of origin determines its number. The numbers increase based
on the alphabetical listing of county names. Albany County has routes 10, 11,
12, 13; Bighorn has 30, 31, 32, 33, 35, 36, 37; Campbell has 50, 51, 59; Carbon
has 70, 71, 72, 73, 74, 76, 77; etc.
Sources:
If you have information on how a state numbers its highways, don't hesitate to e-mail me.