Routing logic from state to state

[TheStranger]

Thought of this when I was looking at Google Maps at the current south terminus of M-39 in Dearborn, which is not quite at I-75 or the nearby M-85, but rather at Lafayette Boulevard between the two:

https://www.google.com/maps/preview/place/Southfield+Rd+%26+Lafayette+Blvd,+Lincoln+Park,+MI+48146/@42.2518053,-83.1818404,17z/data=!3m1!4b1!4m2!3m1!1s0x883b36bf3f4a76e5:0x6d61d6d1ff603137

I also think of Route 160 in Sacramento County, which thanks to relinquishments is discontinuous between Freeport and the Sacramento River - as opposed to signing 160 from Freeport to I-5 at the very least (unlike Route 16's eastern segment a few miles away, which is signed all the way to its endpoint at US 50).

Basically, it's a bit of an open-ended discussion, but I'm curious how each state handles the following:

- Route gaps/signage gaps

- Jurisdiction relinquishments (i.e. California seems to overly base its signing practice on who maintains the road, as opposed to maintaining route continuity)

- Termini: do routes have logical starting and end points (i.e. at another numbered road, or at a major destination in which the road cannot continue on further) or do they seem to start/end at arbitrary intersections?

- Route directness: for instance in California, while US 101 between LA and Anaheim and Route 9 through Boulder Creek eventually got much more direct alignments, what was Route 9 between Saratoga and Milpitas took the indirect Route 85/Route 237 perimeter routing as opposed to the more direct Saratoga Avenue and Trimble Road.

- Using newest possible alignment: best illustrated with US 41 remaining on an older road north of Terre Haute as opposed to the parallel faster IN 63.

[SD Mapman]

SD technically has a lot of route gaps, as multiplexes are not legally defined. However, DOT can extend signage if they want to make a route continuous. (link) Usually routes terminate logically (some east river end at old US 77). There are exceptions, most notably the "river roads" and the southern terminus of SD 53 (That shouldn't even be a route, anyway). We tend to use new alignments and tend to be direct due to the lack of large population centers and landforms (apart from the Hills).

[Doctor Whom]

In Maryland, the various sections of a discontinuous route are designated internally, but not signed, with different letter suffixes.

[Zeffy]

- Route gaps/signage gaps

In New Jersey, the infamous I-95 gap exists due to the Somerset Freeway never being finished; The state handles it (currently) by advising people to stay on I-295 SOUTH (mind you, I-95 NORTH dumps onto 295 SOUTH) until you reach I-195 EAST at which point you can get to the Turnpike from there. It's a sloppy configuration, but uh, you can thank all the rich people in Princeton / Mercer County for that. Luckily, once the I-95 / PA. Tpk. interchange project is finished, that gap will cease to exist, and the current section of I-95 near Trenton will become I-195.

[hotdogPi]

These apply for New England.


New England keeps route numbers across borders within New England and usually into New York too.

New Hampshire has some routes that end on the Massachusetts border: 107A, 121, 122, 123, 124, 128. However, on the Massachusetts side, all routes continue into New Hampshire.

In Massachusetts, routes 1A and 3A are technically multiplexed with 1 and 3 in their gaps.
(And MA 1A becomes US 1A at the Rhode Island border).

Most routes are direct (except those intended to be loops).

Most routes end at other routes (even if they are on the ocean), except in Maine.

Maine has too many US 1A.

[vdeane]

Almost all of NY/New England route crossings keep the number; of those that don't, most end at the border, and the only two that don't (both on the NY/VT border) are understandable and forgivable exceptions:
-NY 7/VT 9, due to the close presence of US 7 on the Vermont side and US 9 on the New York side
-NY 185/VT 17, as NY 185 was designated in 2008 and was a reference route prior to that

[Beeper1]

New England keeps route numbers across borders within New England and usually into New York too.

In Massachusetts, routes 1A and 3A are technically multiplexed with 1 and 3 in their gaps.
(And MA 1A becomes US 1A at the Rhode Island border).

This applies for 6A and 7A as well.   Also, and this is a recent development, but RI has downgraded US 1A to just plain old RI 1A.  All the US 1A shields along the route from the MA line to Cranston have been replaced by RI 1A shields. The only exceptions are the 5 year old BGSs on I-95 at Atwells Ave (exit 18), and one lone shield southbound on the route where it turns off Narragansett Parkway in Cranston.   Not sure if this is official per AASHTO, but seems to be official for RIDOT.

MA and CT each have one route that ends at the border and continues un-numbered:  MA-31 and CT-272. For all real purposes MA-31 can be said to end at CT-197, as it's only about 15 yards of town road between them.  CT-272 could probably be extended as MA-272 to connect eventually to MA-57, but the area is rural and the traffic levels probably don't warrant that. 

[TheOneKEA]

In Maryland, the various sections of a discontinuous route are designated internally, but not signed, with different letter suffixes.

There are also state highways like MD 125 and MD 133, which are separate state-maintained segments of a local county highway. There's also MD 835A, which is the only state highway that is signed with the letter suffix.

In addition, MDSHA only inventories one highway at a time when there is a concurrence between two or more highways, and the SHA doesn't always choose the lowest number. For example, the I-70/US 40 concurrence is only inventoried in the HLR under the I-70 designation, and US 40 is only inventoried on its own when it has it's own routing. On the other hand, the MD 23/MD 165 concurrence in Baltimore County is inventoried as MD 165 only. Lastly, concurrences are often signed intermittently or with TO banners for state highways, making it tough to follow if you miss the directional signage.

[Alps]

New England keeps route numbers across borders within New England and usually into New York too.

In Massachusetts, routes 1A and 3A are technically multiplexed with 1 and 3 in their gaps.
(And MA 1A becomes US 1A at the Rhode Island border).

This applies for 6A and 7A as well.   Also, and this is a recent development, but RI has downgraded US 1A to just plain old RI 1A.  All the US 1A shields along the route from the MA line to Cranston have been replaced by RI 1A shields. The only exceptions are the 5 year old BGSs on I-95 at Atwells Ave (exit 18), and one lone shield southbound on the route where it turns off Narragansett Parkway in Cranston.   Not sure if this is official per AASHTO, but seems to be official for RIDOT.

That is news. Finally, 1A has signage!

[NE2]

But does it have signage on Point Street?

[Beeper1]

Nope.  Signage is still pretty much non existent from where 1A meets 195 in East Providence and the Providence/Cranston line.  No signs at I-195 exit 2 or on Point St or Allens Avenue.  In fact the BGSs at I-95 exit 18 are the only 1A signs anywhere in Prov.   

[mrsman]

Thought of this when I was looking at Google Maps at the current south terminus of M-39 in Dearborn, which is not quite at I-75 or the nearby M-85, but rather at Lafayette Boulevard between the two:

https://www.google.com/maps/preview/place/Southfield+Rd+%26+Lafayette+Blvd,+Lincoln+Park,+MI+48146/@42.2518053,-83.1818404,17z/data=!3m1!4b1!4m2!3m1!1s0x883b36bf3f4a76e5:0x6d61d6d1ff603137

I also think of Route 160 in Sacramento County, which thanks to relinquishments is discontinuous between Freeport and the Sacramento River - as opposed to signing 160 from Freeport to I-5 at the very least (unlike Route 16's eastern segment a few miles away, which is signed all the way to its endpoint at US 50).

Basically, it's a bit of an open-ended discussion, but I'm curious how each state handles the following:

- Route gaps/signage gaps

- Jurisdiction relinquishments (i.e. California seems to overly base its signing practice on who maintains the road, as opposed to maintaining route continuity)

- Termini: do routes have logical starting and end points (i.e. at another numbered road, or at a major destination in which the road cannot continue on further) or do they seem to start/end at arbitrary intersections?

- Route directness: for instance in California, while US 101 between LA and Anaheim and Route 9 through Boulder Creek eventually got much more direct alignments, what was Route 9 between Saratoga and Milpitas took the indirect Route 85/Route 237 perimeter routing as opposed to the more direct Saratoga Avenue and Trimble Road.

- Using newest possible alignment: best illustrated with US 41 remaining on an older road north of Terre Haute as opposed to the parallel faster IN 63.

The examples you cite show bad signing practice on the part of Caltrans.  If the two 16's should continue to exist, then they should in someway indicate a way to go between the two.  If they don't want to do that, then they should renumber one of the sections so that the highways exist as two separate routings. 

For CA-160, if they don't want to do any of the above, a possible third option is to sign County-160.  Use a county shield (like used for the Silicon Valley expressways) instead of a green miner's spade, but keep the number the same.  This at least gives the driver some hope of being able to navigate between the two state maintained sections.

Something like the above already exists in the LA area.  The 110 routing is CA-110 through the Arroyo Seco Parkway, becoming I-110 as the Harbor Freeway, and then continuing as CA-110 when the freeway ends at Gaffey Street in San Pedro.  It allows for a driver to follow 110 from San Pedro to Pasadena, even though only the freeway portion south of I-10 (or is it US 101) is Interstate quality freeway.

San Bernardino County has a county-66 for an old routing of US 66 that is no longer state maintained.  In that case, it was probably done more for nostalgia than for routing, but it may provide a useful option to allow for state decommissioning on other sections of numbered highways that are  really just local streets and should be under local control.

[TheStranger]

The examples you cite show bad signing practice on the part of Caltrans.  If the two 16's should continue to exist, then they should in someway indicate a way to go between the two.  If they don't want to do that, then they should renumber one of the sections so that the highways exist as two separate routings. 

There's already precedent though from the 1960s on to have "split routes" with the existence of effectively two different Route 84s.  Not that I agree with it at all, but it's an established practice.

Even some short, potentially easy-to-sign concurrencies rarely receive that treatment (case in point: Route 193 in Auburn along I-80)

For CA-160, if they don't want to do any of the above, a possible third option is to sign County-160.  Use a county shield (like used for the Silicon Valley expressways) instead of a green miner's spade, but keep the number the same.  This at least gives the driver some hope of being able to navigate between the two state maintained sections.

Except that the segment of Route 160 between the American River and Freeport is not a county road, but maintained by the city of Sacramento (who essentially requested the decommissioning so they could attempt to have 15th/16th be less highway-like in midtown).  This is a case where the two remaining segments really should be numbered differently.

Something like the above already exists in the LA area.  The 110 routing is CA-110 through the Arroyo Seco Parkway, becoming I-110 as the Harbor Freeway, and then continuing as CA-110 when the freeway ends at Gaffey Street in San Pedro.  It allows for a driver to follow 110 from San Pedro to Pasadena, even though only the freeway portion south of I-10 (or is it US 101) is Interstate quality freeway.

Gaffey Street has not been a state highway since the late 90s (I was there about two months ago and saw no signage whatsoever on it).

[agentsteel53]

(case in point: Route 193 in Auburn along I-80)

or, Hell, I-10 along I-5.  it's occasionally signed but not nearly consistently enough to be navigationally useful.

the first few times I drove the East LA Interchange, I had to consciously keep reminding myself that there were, effectively, two I-10s.

[TheStranger]

(case in point: Route 193 in Auburn along I-80)

or, Hell, I-10 along I-5.  it's occasionally signed but not nearly consistently enough to be navigationally useful.

the first few times I drove the East LA Interchange, I had to consciously keep reminding myself that there were, effectively, two I-10s.

It's amazing how 580/80 signage has improved over time (especially after the north split in Albany was reconfigured in the 1990s)...while 10/5 signage, which has existed since the Golden State Freeway was completed in the 1960s, has become less consistent.

District-to-district autonomy!

Makes me wonder which CalTrans district is the most consistent at marking co-signed routes:

- District 4 obviously is pretty good with 101/84 and 580/80, but 101/1 around SF and Marin has been hit-or-miss as of late

- District 5 is decent for 101/156 but piecemeal for 101/1 through Santa Barbara County

- District 3 has some of the most blatant unsigned concurrencies (193/80, 16/50) but does still have a okay set of trailblazers for 99/5

- District 7 is home to the aforementioned 10/5 situation, though 101/23 is handled well (along with the very edge of 405/22)

[Urban Prairie Schooner]

In Louisiana route discontinuities are rare, and when they do exist are due to the state relinquishing control of a section of highway to localities. In nearly ever case DOTD assigns one of the orphaned segments a new route number. The only extant discontinuity I can think of is LA 120.

[SSOWorld]

WI does not end routes appropriately well - running secondary routes along another route and ending them concurrently (WIS-70/101, WIS-47/182) or run a route along another for a while before ending it midway (WIS-34 after the WIS-13 reroute onto it and DON'T GET ME STARTED on I-41!!!!), or redundant routes.  They don't use single-digit state routes (the only single digit routes are US 2 and US 8).  WIS 32, 35, 42, 47, 57 are the stage actors of concurrencies - not to mention the triple interstate or quad-US concurrency on the Beltline.

[roadman65]

I think its odd that SC does not allow US 15 to be concurrent with US 17 ALT between Walterboro and its southern terminus.  Considering that US 521 is concurrent with the very same US 17 ALT at its other end, you would figure consistency here.   Yes, I am aware that US 15 is now a shadow route to I-95, but US 15 ended at Walterboro long before the interstate was constructed. 

[mrsman]

(case in point: Route 193 in Auburn along I-80)

or, Hell, I-10 along I-5.  it's occasionally signed but not nearly consistently enough to be navigationally useful.

the first few times I drove the East LA Interchange, I had to consciously keep reminding myself that there were, effectively, two I-10s.

It's amazing how 580/80 signage has improved over time (especially after the north split in Albany was reconfigured in the 1990s)...while 10/5 signage, which has existed since the Golden State Freeway was completed in the 1960s, has become less consistent.

District-to-district autonomy!

Makes me wonder which CalTrans district is the most consistent at marking co-signed routes:

- District 4 obviously is pretty good with 101/84 and 580/80, but 101/1 around SF and Marin has been hit-or-miss as of late

- District 5 is decent for 101/156 but piecemeal for 101/1 through Santa Barbara County

- District 3 has some of the most blatant unsigned concurrencies (193/80, 16/50) but does still have a okay set of trailblazers for 99/5

- District 7 is home to the aforementioned 10/5 situation, though 101/23 is handled well (along with the very edge of 405/22)

The Caltrans districts operate as though they are different state DOTs.  There is no consistency.

[roadman65]

FDOT is the same way.  Not all districts allow 60 mph on two lane roads, as allowed by law.  Then D 4 following the cardinal direction ruling by the book for US 98, while D1-, D 2, and D 7 allowing it to be signed N-S through the peninsula. 

The signing was even different at one time.  The Panhandle used two posts to support a speed limit sign on interstates, while the rest of the state used one.  Now all interstates use two posts on speed limit signs, however only D 1 and D 7 maintain the minimum speed limits while the rest of Florida ditched them back in the 90's.

[doogie1303]

New England keeps route numbers across borders within New England and usually into New York too.


In Massachusetts, routes 1A and 3A are technically multiplexed with 1 and 3 in their gaps.
(And MA 1A becomes US 1A at the Rhode Island border).

This applies for 6A and 7A as well.   Also, and this is a recent development, but RI has downgraded US 1A to just plain old RI 1A.  All the US 1A shields along the route from the MA line to Cranston have been replaced by RI 1A shields. The only exceptions are the 5 year old BGSs on I-95 at Atwells Ave (exit 18), and one lone shield southbound on the route where it turns off Narragansett Parkway in Cranston.   Not sure if this is official per AASHTO, but seems to be official for RIDOT. 

One of the best examples of a route number being used by multiple states in southern New England is Route 138. It starts in Sprague, CT then goes west->east thru RI and ends in Milton, MA. Same route, 118 miles across three states.

As far as 1A goes, yeah RI for some reason doesn't like signing "Alternate" Routes as U.S highways but rather as state roads. In Washington county, they sign 1A as RI "scenic" 1A, which look like RI state route markers except they are lettered in green. But I agree that it is used to be signed as U.S routes as I remember a while back seeing a U.S. 1A shield when I was passing through Wickford, RI. That shield has now been replaced with a RI "scenic" 1A marker.

[Laura]

In Maryland, the various sections of a discontinuous route are designated internally, but not signed, with different letter suffixes.

There are also state highways like MD 125 and MD 133, which are separate state-maintained segments of a local county highway. There's also MD 835A, which is the only state highway that is signed with the letter suffix.

In addition, MDSHA only inventories one highway at a time when there is a concurrence between two or more highways, and the SHA doesn't always choose the lowest number. For example, the I-70/US 40 concurrence is only inventoried in the HLR under the I-70 designation, and US 40 is only inventoried on its own when it has it's own routing. On the other hand, the MD 23/MD 165 concurrence in Harford County is inventoried as MD 165 only. Lastly, concurrences are often signed intermittently or with TO banners for state highways, making it tough to follow if you miss the directional signage.

Fixed it for you.

Also, "Officially there's still a 1.28 mile break in the route along 165 between the old and new 23; it's not dual-signed with 165, only "TO MD 23"." My guess is that since MD 23 was origi

Maryland routing logic weirdness in a nutshell:

1) If the sections of a road under state maintenance aren't connected, they get different route numbers (such as Old Court Road - MD 125 and 133, mentioned earlier.)
2) Additional sections of a route (like exit ramps) get suffixes (like MD 24D for the connecting ramps to US 40).
3) Old alignments are usually assigned the same number per region, but don't have to be connected.  An example is how old US 40 is MD 144 west of Baltimore and MD 7 east of Baltimore.
4) There will always be exceptions to these rules, such as our dear friend MD 23.

I'm not sure about the inventory thing you mentioned, but I wouldn't be surprised if that is the case.

[Rover_0]

Utah generally avoids route gaps, but the two routes with the most noticeable gaps (SR-30 and SR-73) have several-mile gaps and are major routes.

Part of that is that UDOT and the Legislature don't recognize state route concurrencies, so at best you see "implied" concurrencies, like SR-68/48 in South Jordan:



And US-89/SR-30 from Logan-Garden City:


Once you turn onto the concurrency, however, you'll only see the primary route signed, like in Logan:


Now this practice also has led to many absent US Routes on Interstates, most notoriously US-189, which still, according to UDOT, "ends" at US-40 in Heber City though in reality it follows US-40 and I-80 into Wyoming (documents even say so!). However, some previously unsigned concurrencies, such as I-15/US-50 between Holden and Scipio, are now for all intents and purposes signed. There's a lot to do (especially with SR-30, I-70/US-50/US-6 and US-189), but progress is slowly being made.


If a route is maintained by the state, it gets a number. If not, it receives no number. Simple as that. Even routes that aren't technically highways, which fall into the 281-320 range, get a number. Any UT-3xx route serves a state park, while 280-299 serves a state institution, such as the state prison (SR-287) or universities (SR-282, SR-290, etc.).
Going back to SR-73, the city of Lehi wanted jurisdiction of Main St. from 850 E. out to SR-68 (Redwood Rd.), and as such, SR-73 now is split into two segments, though I feel that the eastern stub from 850 E. in Lehi (pretty much I-15) to US-89 should have a different number, like SR-181.

Also, many of these 281-320 and other short routes (such as UT-197 in Lehi and UT-212 in Washington City) are gradually being relinquished back to local jurisdiction.


Again, as a road (or parking lot, or driver's testing grounds, etc., as it may be) maintained by UDOT gets a number, as soon as jurisdiction ends, the state route ends. These usually are some kind of point of interest, though SR-212--while it was around--ended at 300 E. in Washington City, but that's where state jurisdiction ended.


For the most part, routes are routed along the most direct route, though sometimes they retain virtually the same route that they always have, regardless of directness.


Generally, a route will be aligned along a newer alignment, such as US-89 bypassing Redmond (SR-256 takes the old route), with the old alignment getting a new number (should it stay under UDOT jurisdiction) or being removed from the state system (if it doesn't).


Another quirk I've noticed: Utah may be holding single-digit numbers for major routes, somewhat different from its normal number-clustering scheme.
Originally, Utah used a hierarchical system with the most major routes (US-91, then its successor I-15 being SR-1, US-40 then I-80 being SR-2, and so forth).

A UDOT employee said that "when enough time passes" SRs 1 through 5 may be used, implying that not all single-digit routes may not be confined to the southwestern corner of the state, if the regular cluster method were followed. UT-8 is the major-route anomaly, though it may be planned for the future Western Corridor of the St. George Beltway (I-15 west, then north to Sunset Blvd. in Ivins) or removed from the state system entirely (all 1.02 miles of it).

[NE2]

Rover: are you aware of this former method of marking SR 30?

[Rover_0]

Rover: are you aware of this former method of marking SR 30?

Sure am. That was before or around the 1977 renumbering--when UDOT ditched the hierarchical legislative route method and matched legislative numbers with signed numbers.

Still, UT-30 became--and still is--discontinuous as SR concurrencies are neither recognized or signed. It's pretty odd that a border-to-border route is split into 3 distinct, separate segments with no indication of how to travel between said segments (though it is straightforward between Logan and Garden City). Either UT-30 should be referenced along I-84, I-15, and US-89, or its segments should be given separate numbers.

It's also ironic that not long after Utah decided to number this border-to-border route (in the field, at least) SR-30 (after NV-30), Nevada renumbered NV-30 to NV-233 in their great renumbering.