Ever try to "crack the code" for Interstate control cities?

[bandit957]

Every try to figure out what criteria they use to determine Interstate control cities?

When I was a teenager in the late '80s, I noticed the Interstate control cities in Cincinnati were Lexington, Louisville, Indianapolis, Dayton, and Columbus. These are pretty much unassailable, as there's no other cities that might rival those. We went on a family trip to Nashville, and I think the control cities were Knoxville, Chattanooga, Birmingham, Memphis, St. Louis, and Louisville. The next year, we went to St. Louis, and I think the control cities were Kansas City, Chicago, Indianapolis, Louisville, Memphis, and Tulsa. So I figured control cities would have to be pretty big. Springfield, Mo., and Springfield, Ill., were not control cities.

But on I-64 east of Lexington, the main control city was Ashland. On I-70 east of Columbus, it was Wheeling. Those cities are smaller than either of the Springfields. On the other hand, it's a long way until any really big cities on those routes.

Was there a rule or any sort of official recommendation about what cities would be control cities? Was it, say, 150,000 unless there's a gap of 200 miles or something, in which case it was 50,000 or even 25,000 in some cases?

[ran4sh]

Each state had its own determination of which control cities they would use, some states favored in-state and/or smaller cities while other states favored larger cities, and some states like Illinois try to split the difference by having two tiers of control cities, despite message loading concerns.

[Scott5114]

Springfield MO appears as a control city once you get further away from St Louis. My guess is that MoDOT didn't want to have to distinguish between Springfield MO and Springfield IL.

[ozarkman417]

The absence of Springfield in St. Louis area signs is also what led me to attempt to figure out the criteria of control cities. Specifically, Between MO-141 and US-63 the control city of West I-44 is Rolla. US-63 onward the control city is Springfield.

From this, I've determined that Missouri generally uses the next decently sized city where the highway intersects a U.S Route. How I got to this pattern was as such:
-Joplin has US 71
-Springfield has US 65
-Rolla has US 63
-St Louis has.. several.
The "decently sized" part is important. On I-70, its simply logical to have Columbia (US 63) as a control city instead of Kingdom City (US 54).
Even when it comes to non-interstates, US Routes matter. While Mountain Grove and Willow Springs are larger than Cabool, Cabool is the control city coming from the west on US 60, as it is where it intersects US 63.

Like Scott said, if Springfield were to be a St. Louis control city, a state suffix would be required. In fact, MoDOT already uses suffixes on signs like this.

[Ted$8roadFan]

I always thought Rhode Island using I-95 south of Providence with New York as a control city was a little off.  They could find another city in between (and state routes themselves use Westerly and New London.   

[HighwayStar]

There is no code, even states with some objective criteria have nonsensical examples.
Like numbering generally, leaving the determination of control cities to the states guarantees a deeply confusing mix of standards with little consistency.

[SkyPesos]

The absence of Springfield in St. Louis area signs is also what led me to attempt to figure out the criteria of control cities. Specifically, Between MO-141 and US-63 the control city of West I-44 is Rolla. US-63 onward the control city is Springfield.

From this, I've determined that Missouri generally uses the next decently sized city where the highway intersects a U.S Route. How I got to this pattern was as such:
-Joplin has US 71
-Springfield has US 65
-Rolla has US 63
-St Louis has.. several.
The "decently sized" part is important. On I-70, its simply logical to have Columbia (US 63) as a control city instead of Kingdom City (US 54).
Even when it comes to non-interstates, US Routes matter. While Mountain Grove and Willow Springs are larger than Cabool, Cabool is the control city coming from the west on US 60, as it is where it intersects US 63.

Like Scott said, if Springfield were to be a St. Louis control city, a state suffix would be required. In fact, MoDOT already uses suffixes on signs like this.

MoDOT is highly inconsistent with control cities. Besides I-44, I-70 WB starts off with a control city of Kansas City in St Louis County, then switches to Wentzville after crossing into St Charles County, then uses various cities between St Louis and KC (most notably Columbia).

[TheHighwayMan3561]

You get some states that use different control cities along the same stretch, like Minnesota (which I hate) doing things like putting Duluth for I-35E at I-694, which is right, but at interchanges between 694 and 35W will post Forest Lake, which is a useless and dumb control.

[MATraveler128]

Florida seems to list random control cities based on the District. For example, you will see Miami being used at the end of I-4 in Daytona Beach, but as you get to Fort Pierce, it changes to West Palm Beach.

[bandit957]

I think in Richmond, Va., they usually use Rocky Mount, N.C., but I think I once saw Miami used.

[ran4sh]

Miami and Atlanta in the Richmond-Petersburg area of Virginia are not really control cities, they're only used to guide long-distance traffic at the I-95/I-295 and I-95/I-85 interchanges. They're not used on distance signage and they're not used from local roads.

[thspfc]

I cracked the code for Pennsylvania: take whichever local municipality helps travelers the least, and put it on as many BGSes as possible.

[achilles765]

It seems to be very much a state specific thing. 

I think of the three states in which I have lived and done most of my driving-- and they are all very different.

Louisiana is a state with only two cities that can be considered "big" and several smaller cities...only Metairie, New Orleans, Baton Rouge,Shreveport and Lafayette have populations over 100,000 ( like 140,000; 400,000; 300,000; 110,000; and 100,000 respectively if I remember/estimate correctly) but each is important as regional hubs.  Louisiana tends to sign major cities or cities where there is a major highway-highway junction.
Ex: on I-10: Lake Charles, Lafayette, Baton Rouge, New Orleans...then Slidell because three 2dis meet there.
on I-12: Baton Rouge, Hammond (jct I-55) and Slidell (jct I-10/I-59)
on I-20: Dallas, Shreveport, Monroe (regional hub), Vicksburg (regional hub)
on I-49: Lafayette, Opelousas (which is the odd one and a leftover from when I-49 ended there), Alexandria, Shreveport, and now, Texarkana.  Either New Orleans or Morgan City seem to be the likely future southbound controls, though Houma-Thibodeaux would make more sense.  On I-55, its New Orleans, Hammond, Jackson. 

Mississippi, on the other hand will list rather small and unremarkable control cities.  I-55's from South to North are New Orleans (south of McComb), McComb (a town of 15,000), Brookhaven (same size as McComb) Jackson (state capital), Granada (worse than McComb), and Memphis (which is appropriate).
I-59?: New Orleans, naturally; then Hattiesburg, Laurel, Meridian, and Tuscaloosa. 
For I-20: Monroe, Vicksburg, Jackson, Meridian
I-10: New Orleans, Bay St Louis (why?) Pascagoula (also why) and Mobile
The thing about Mississippi, though is that there are not really any truly large or substantial cities.  Jackson is the largest and it has barely 150,000 people. So they use any city with over 10,000 people it would seem.

Then there is my adopted home...Texas.  Now Texas signs Interstates and US/State Highway Freeways differently. Interstate almost always use a major city because Texas has like 9 cities with populations over 300,000, and at least 5 with populations of over 1 million.  The older interstates have control cities that seem obvious for the most part:
I-10: El Paso, San Antonio, Houston, Beaumont (regional hub), Lake Charles (first major city in next state...and a major industrial destination). One can also find the occasional Van Horn sign in El Paso, but its rare.
I-20: El Paso (via I-10), Odessa, Abilene, (both regional hubs), Ft Worth, Dallas, Shreveport--all make sense
I-27: Lubbock, Amarillo.  The only two cities on the route...both regional hubs
I-30: Abilene (via I-20), Ft Worth, Dallas, Texarkana
I-35: Laredo (small city but on the border), San Antonio, Austin, Waco (regional hub? some don't like this one but I don't mind); then splits into 35W: Ft Worth, Denton (where they rejoin into I-35); and 35E: Dallas, Denton; OK City
I-37: San Antonio, Corpus Christi.  Some signs now also list Rio Grande Valley, as I-37 connects to US 281 and I-69 E (and later 69C and 69W which will all lead into the RGV)
I-40: Albuquerque, Amarillo, OK City...the three major cities in a row
I-44: Wichita Falls, but then also some weird ones: Burkburnett...and Lawton?

So Texas uses major cities because we have them...but then we have all our new routes...
Interstate 2: not sure about west end, but Harlingen, MCAllen....
Interstate 14: Belton, Temple, Copperas Cove...only places it goes now...
Interstate 69: Victoria, Houston, Cleveland (all remnants of US 59...I would think once its all I-69 it would change to Corpus Christi, Houston, Texarkana...

[SkyPesos]

Ohio 2dis:

Is the interstate I-77?

If No:
- List the next major and/or notable city on its route, like what control cities are supposed to be.

If Yes:
- List an arbitrary Ohio River small city for the southbound direction south of the Cleveland-Akron-Canton area, instead of something more notable (and not that much farther away) like Parkersburg, WV.

[Hot Rod Hootenanny]

Ohio 2dis:

Is the interstate I-77?

If No:
- List the next major and/or notable city on its route, like what control cities are supposed to be.

If Yes:
- List an arbitrary Ohio River small city for the southbound direction south of the Cleveland-Akron-Canton area, instead of something more notable (and not that much farther away) like Parkersburg, WV.

So what's the difference between Marietta & Parkersburg?

[SkyPesos]

Ohio 2dis:

Is the interstate I-77?

If No:
- List the next major and/or notable city on its route, like what control cities are supposed to be.

If Yes:
- List an arbitrary Ohio River small city for the southbound direction south of the Cleveland-Akron-Canton area, instead of something more notable (and not that much farther away) like Parkersburg, WV.

So what's the difference between Marietta & Parkersburg?

Only 10 miles south of Marietta, larger city, and junction with a 4 lane E-W highway (US 50/Corridor D).

If we're including major junctions too, Cambridge is fair game as a control city on I-77 as well.

[Great Lakes Roads]

For Indiana, it's the next "major" sized city on the way (with my recommendations in paratheses):

I-64: St. Louis (how about Evansville as a secondary control city?), Louisville
I-65: Chicago (Lafayette as a secondary control city), Indy, Louisville
I-69: Memphis? (when I-69 eventually reaches that city), Evansville (Bloomington as a secondary control city), Indy, Fort Wayne, Lansing
I-70: St. Louis (Terre Haute as a secondary control city), Indy, Dayton (Richmond as a secondary control city)
I-74: Peoria (maybe replace it with Champaign), Indy, Cincinnati
I-80/90: Chicago, Ohio (replace it with South Bend and/or Toledo)
I-94: Chicago, Detroit

[epzik8]

I think in Richmond, Va., they usually use Rocky Mount, N.C., but I think I once saw Miami used.

Historically, both have been on one sign.

[fillup420]

North Carolina keeps it pretty consistent with signing the next decently sized city, usually one with an important junction.

I do find it odd that on I-77 in Virginia, Charlotte NC is signed from at least the I-81 split, but as soon as you cross the border to NC, Statesville is the primary control city until you reach I-40.

[Dirt Roads]

North Carolina keeps it pretty consistent with signing the next decently sized city, usually one with an important junction.

Not sure that Elkin (pop. 3971) fits either of those two categories.

[andrepoiy]

Ontario's is not that hard to crack with regards to the 400-series freeways.

It's pretty much the next large settlement that isn't too close to the previous city. And preferably in Ontario

For example, on Hwy 401 it's

Windsor (pop 300k) -> London (pop 400k) -> Toronto (pop 2.7 mil) -> Kingston (pop 100k) -> Cornwall (46k) -> Montreal (pop 1.7 mil)

Hwy 403:

London (pop 404k) -> Hamilton (pop 500k) -> Toronto (pop 2.7 mil)

Hwy 404:

Toronto (pop 2.7 mil) -> Newmarket (pop 80k) -> no control

Hwy 400:

Toronto (pop 2.7 mil) -> Barrie (pop 200k) -> Parry Sound (pop 6000) -> Sudbury (pop 100k).



On the contrary, I've noticed that Quebec instead posts cities farther away.

For example, on Aut 20 in Montreal, signs point to Toronto.... even though the 401 signs don't say Toronto until you get to Kingston.
Aut 40 points to Ottawa and Quebec City.

I have noticed that Aut 15 has closer cities... Montreal to Laval to St Jerome and on and on

[golden eagle]

Mississippi, on the other hand will list rather small and unremarkable control cities.  I-55's from South to North are New Orleans (south of McComb), McComb (a town of 15,000), Brookhaven (same size as McComb) Jackson (state capital), Granada (worse than McComb), and Memphis (which is appropriate).
I-59?: New Orleans, naturally; then Hattiesburg, Laurel, Meridian, and Tuscaloosa. 
For I-20: Monroe, Vicksburg, Jackson, Meridian
I-10: New Orleans, Bay St Louis (why?) Pascagoula (also why) and Mobile
The thing about Mississippi, though is that there are not really any truly large or substantial cities.  Jackson is the largest and it has barely 150,000 people. So they use any city with over 10,000 people it would seem.

Bay St. Louis is a control from I-10 in Slidell because there was a time when I-10 wasn't completed all the way in Mississippi. Drivers had to get off at BSL. Same with Pascagoula in Mobile.

I'm not sure what the deal is with McComb and Grenada.

[US20IL64]

"I-80/90: Chicago, Ohio (replace it with South Bend and/or Toledo)

IDOT used to have Toledo and Des Moines on BGS at I-55/80 interchange, now Indiana and Iowa. I remember my father saying 'Toledo?', wondering why such a far away place, on a trip to STL on 55.

[SkyPesos]

"I-80/90: Chicago, Ohio (replace it with South Bend and/or Toledo)

IDOT used to have Toledo and Des Moines on BGS at I-55/80 interchange, now Indiana and Iowa. I remember my father saying 'Toledo?', wondering why such a far away place, on a trip to STL on 55.

The funny thing is that Toledo is closer to Chicago than St Louis is. Probably seems farther away because it's 2 states over, instead of 1.

[Ted$8roadFan]

I think there was a time in the past when the Ohio Turnpike near Youngstown used New York City as a control city for I-80 (or at least on its mileage signs). Then, once it crosses the border into Pennsylvania, the Commonwealth would revert to using its own control cities (Sharon, Clarion, etc.)