I strongly support state route extensions of Interstates. New York uses them a lot. Arkansas has one, the AR 440 freeway which is an extension of I-440 (and will one day be I-440. It could be argued that it should be signed as a future Interstate or a full-blown Interstate because it ends at a major freeway (US 67-167/Future I-30.) There used to be AR 540, but all segments of it were decommissioned in favor of I-540. There is also AR 530, a secluded stretch of two-lane highway that will one day be part of I-530/the I-69 connector. One place that would be a good candidate for this is Chenal Parkway in Little Rock. It seamlessly flows into Financial Center Parkway which seamlessly flows into I-630. Chenal/Financial Center Parkways would make a dandy AR 630, ending at AR 10. Unfortunately, Chenal Parkway is not maintained by AHTD.
Do you like the idea of state routes continuing the number of an Interstate? If not, why? If so, why?
I'm pretty neutral on this. It makes sense if the extension is planned to eventually be upgraded to interstate, like your examples and others. If no extension of the interstate is planned, though, it still might make sense as it guides motorists along the state route to the interstate.
It could cause confusion, though, if the state route were confused with the interstate. You pull onto SR-xxx, then get lost because you were expecting a freeway.
I like them. I think they're a useful way to continue an interstate routing with the same number when the extension can't be made part of the interstate for some reason. AR 540 was a useful number to use for the unfinished freeway between Fayetteville and I-40 because while it couldn't be signed as I-540 until it was finished, it gave an indication that the road would be part of I-540 eventually and it got people used to the 540 number, even though it eventually changed from AR 540 to I-540. AR 440 makes perfect sense for the connector between US 67 and I-40, especially for travelers continuing on I-440, though I don't know why they can't just sign it as I-440 now-it appears to be built to interstate standards. I also like what Tennessee does with TN 840 which for all practical purposes works as a loop and bypass interstate and follows the interstate numbering convention as an x40, and can be easily changed to I-840 someday if they want to do so.
Personally, I like it when a route has one number, regardless of "type" (though my preference is for the route to be one "type" as much as possible).
i.e. I-110/Route 110 makes some sense, though part of me thinks the Arroyo Seco Parkway (Pasadena Freeway), being more east-west, should be signed as Historic Route 66 instead.
I-15/Route 15 is an example of a future interstate on the south end, though considering how many roads have been grandfathered into Interstate standards, why not just sign it all as I-15?
I understand why I-880 and Route 17 don't have this (17 is a 1934-era route, of which 880 subsumed the middle 45 miles of it) but I almost feel that with the precedent set by I-635 (does not end at another Interstate now), why not extend 880 south to Route 85? Then have State Route 880 continue the final 25 miles to Santa Cruz, so that we don't get the odd situation of the through route's exit numbers resetting at I-280 as currently is the case.
Quote from: TheStranger on July 10, 2010, 02:03:10 AM
(17 is a 1934-era route, of which 880 subsumed the middle 45 miles of it)
really? I had heard that expressway between I-880 and Santa Cruz was built as a four-laner (originally undivided) in 1940, replacing the old highway. As for the north section, which became 580, I do not know when that was built in general but isn't the San Rafael bridge from 1956?
Quote from: agentsteel53 on July 10, 2010, 02:07:36 AM
Quote from: TheStranger on July 10, 2010, 02:03:10 AM
(17 is a 1934-era route, of which 880 subsumed the middle 45 miles of it)
really? I had heard that expressway between I-880 and Santa Cruz was built as a four-laner (originally undivided) in 1940, replacing the old highway. As for the north section, which became 580, I do not know when that was built in general but isn't the San Rafael bridge from 1956?
IIRC, Route 17 was originally planned as Route 13 in 1934, then switched to 17 soon after (not sure if this 13 was ever signed) - amusing when you consider that 13 shows up in the 1964 renumbering without any superstitiousness stopping it, while we know what happened to post-1964 69! :-D
http://members.cox.net/mkpl2/hist/droz-sjsaca42.jpg shows 17 existing by 1942 in downtown San Jose.
You were right in 17 not being 1934-era per se, though I was working on the assumption that the corridor was at least planned to be signed as 13 that year...to quote CAHighways:
QuoteIn 1934, what is now Route 17 was signed as Route 13. By 1936, it appears to have become Route 17. The routing between Santa Cruz and San Jose appears to have been completed in 1940, although much of it was three lanes (suicide lane in the center). The only exception is the portion through the now-submerged towns of Lexington and Alma; with the construction of the reservoir, the alignment was moved to the west around 1950. The last section of freeway opened in San Jose was the section between Bascom Ave and US 101; this opened in 1960. Until this was completed, the Route 17 roluting was from San Carlos Street, then Race Street, The Alameda, onto Santa Clara Street. From Santa Clara Street, 13th Street, Old Bayshore Highway, to the end of the Nimitz Freeway at Gish Road.
The concept of a state route designation continuing the Interstate number on the same highway or freeway facility just makes good sense. This is especially true when the local portion is ultimately planned to be given an Interstate designation in the future.
The idea isn't just limited to state routes, though. The 53-mile Las Vegas Beltway has the Clark County 215 designation which continues from I-215. The entire beltway will eventually become I-215, but only about 30 contiguous miles are currently constructed to Interstate standards with only 12 miles currently designated as Interstate. I support this numbering scheme, as it easily allows Las Vegans to refer to the beltway as "the 215".
There really is no good reason why a route should suddenly change numbers. So, yeah, continuing past the interstate portion as a state route of the same number is only logical.
An additional point, though: not only should the number continue across the class change, but both routes should share the same set of mile markers and (if some or all of the state route is freeway) exit numbers.
CT did this in the early 1960s: CT 184 (formerly 84) was signed CT 95, as an extension of I-95, until I-95 was completed in 1964.
I guess CT 66 could become CT 691, to the annoyance of eastern towns along its route.
I personally like the idea as long as the signed state route has a direct connection to the interstate that it shares a number with. That way it avoids confusion and allows people to continue on the same numbered road. I hate it when states like Maryland signs a state route with the same number as a existing interstate within the state with MD 70, 195 and 270. Although they are in different parts of the state than their interstate counterparts it is still a massive thorn in my side.
Illinois has done it with both interstates and US highways IL 336 is realted to 36 before it became 72
Right now it has signed the Alton ByPass as IL 255 as an extension as I 255 I know IDOT and the locals want it signed all the way to its merger with 67