Sequential exit numbering & conversion to milepost exit numbering

[jdb1234]

Mississippi also used sequential based exit numbers on some stretches of its freeway originally, and mileage based on others. Froggie can tell you when the change to all-mileage based numbers occurred...

Sometime in the 1980s.

Georgia uses sequential-based exit numbers on three freeways that I can think of -- Georgia 400, U.S. 80/J.R. Allen Pkwy. and U.S. 78/Stone Mountain Freeway. The Interstates have been mile-based for at least ten years.

IIRC, the Georgia Interstate changeover was more recent than that...

The Georgia changeover occurred in 1999.

Alabama used KM posts on its freeways in 1996. They were turned sideways later and then removed. I saw a remaining KM post on the I-10 Bayway as recently as late last year...

I remember that.  The KM posts were done for the Olympics.  There are still a few around in Birmingham that I know of.

[myosh_tino]

If NY goes milepost, they might have to reverse the numbers on the Thruway.

How about going from NO exit number to milepost (say California and the Illinois Tollway )

California is (slowly) installing them, but seems to lack the typical interstate mileposts.  The ISTHA has standard interstate type mileposts, but is looking into installing some sort of exit numbering system (discussed over in the Tollway Milemarker thread in the Midwest section).  They could easily add numbers to the exits.

Yeah, slowly is an understatement.  The project to add exit numbers was launched in 2002 and should have been completed by now but because of a lack of funding completion has been delayed until who-knows-when.

Regarding mileposts, California uses "postmiles" which measure the route's length within a county.  Since all maintenance records and project documents make use of postmiles, there is very little incentive for Caltrans to spend money installing standard mileposts.  Once again, this being Caltrans, there is one exception.  Mileposts were installed on the CA-58 Mojave Bypass when it opened for traffic a few years ago and have since been extended west over the Tehachapi mountains almost to Bakersfield and east to Boron.

Here's a StreetView image of a CA-58 milepost...
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=mojave,+ca&sll=29.728887,-95.440378&sspn=0.002148,0.003449&ie=UTF8&hq=&hnear=Mojave,+Kern,+California&ll=35.043714,-118.110825&spn=0.001012,0.001725&z=19&layer=c&cbll=35.04382,-118.110875&panoid=y-EE7dAiMZex20oUzgXAVQ&cbp=12,35.06,,1,11.58

[Michael]

Unlike most people in this thread, I like sequential numbering and hate distance-based numbering.  I find it too difficult to figure out the distance between exits in my head.  The only time I do like distance-based numbering is when I'm going through an entire state heading west or south.  It tells me the remaining distance on the road in that state.

Fortunately for me, New York has sequential numbering! :partyhat:

[hbelkins]

Kentucky did not use exit numbers at all for years, until the mid-1970s or so, except for the KY 418, US 60, US 27/68 and KY 922 exits on I-75 near Lexington, which were sequentially-numbered. In the mid-1970s Kentucky installed mile-based exit signs on the Mountain Parkway and it was during that time that mile-based markers were added to the exit signs for interstates.

[PAHighways]

It looks like in Pennsylvania that they did number the Northeast Extension (I-476) and the "minor" turnpikes (PA 60/Future I-376, PA 43, etc.) to fit the exit numbering of the overall route.

PA 43/PA Turnpike 43, 66, and 576 following the numbering conventions of north-south and east-west routes.  PA Turnpike 60 is the odd man out because it sits in the middle of PA 60 and PennDOT didn't do mileage-based exit numbers on their US and PA designated expressways.

[Bickendan]

A-7 and AP-7 are two different roads. In the end situation, you'll have a tolled AP-7 and a toll-free A-7 running next to eachother along the east coast of Spain. AP roads use sequential, A roads use kmposts.

While they are two different roads, both A and AP 7 fall in the situation I described in my last post.
Other noted routes: AP 4 between Cadiz and Seville uses km; AP 6 northwest of Madrid retains the distance-based exits that A 6 uses; A 8 switches from distance to sequential as it becomes a toll, non-AP route as it approaches France and AP 66 follows the same pattern that A 6 uses.

I haven't checked the other routes yet.

[TheStranger]

Yeah, slowly is an understatement.  The project to add exit numbers was launched in 2002 and should have been completed by now but because of a lack of funding completion has been delayed until who-knows-when.

The Sacramento area is full of numbered exits nowadays, with US 50 receiving them east of Route 99 last year, and west of Route 99 in the last few months.  The only freeway that is sorely lacking in numbers now is probably Business 80 north of the 99/50 junction...

I think the Bay Area is also finally starting to catch up as well.

[roadfro]

Unlike most people in this thread, I like sequential numbering and hate distance-based numbering.  I find it too difficult to figure out the distance between exits in my head.  The only time I do like distance-based numbering is when I'm going through an entire state heading west or south.  It tells me the remaining distance on the road in that state.

Fortunately for me, New York has sequential numbering! :partyhat:

You don't like distance-based exit numbering, because it's difficult to do mileage estimations in your head.  So you prefer sequential exit numbering, which gives you absolutely no distance information...   

[mightyace]

It looks like in Pennsylvania that they did number the Northeast Extension (I-476) and the "minor" turnpikes (PA 60/Future I-376, PA 43, etc.) to fit the exit numbering of the overall route.

PA 43/PA Turnpike 43, 66, and 576 following the numbering conventions of north-south and east-west routes.  PA Turnpike 60 is the odd man out because it sits in the middle of PA 60 and PennDOT didn't do mileage-based exit numbers on their US and PA designated expressways.

Thanks for the clarification.

And, the PA 60 problem will go away soon once it becomes I-376! 

[mightyace]

Unlike most people in this thread, I like sequential numbering and hate distance-based numbering.  I find it too difficult to figure out the distance between exits in my head.  The only time I do like distance-based numbering is when I'm going through an entire state heading west or south.  It tells me the remaining distance on the road in that state.

Fortunately for me, New York has sequential numbering! :partyhat:

You don't like distance-based exit numbering, because it's difficult to do mileage estimations in your head.  So you prefer sequential exit numbering, which gives you absolutely no distance information...   

I can do the math in my head and I still like sequential numbering.  As for distance, that's what the Atlas is for.  And, I have a hard time remembering mileage-based exit numbers so if I have to open up an atlas it is only slightly easier to use the mile markers than add it up. 

But, mainly, having grown up in PA, that's what I was used to.  I can recite from memory nearly every road that is at each exit on I-80 and the PA Turnpike Mainline and Northeast Extension under the sequential system, but I can't remember what their mileage numbers are.

For example, I know the main Clarion exit on 80 was #9, Clearfield was #19, Milesburg was #23, US 15 was #30, I-180/PA 147 was #31, my parents' house was at exit #36S, the Northeast Extension was exit #42 and Pocono Raceway was at Exit #43.  Exit #43 was appropriate for Pocono Raceway as Richard Petty drove the #43 for most of his career.  The only one of those that I remember off the top of my head in the new scheme is that my parents' house is at Exit 241A.  (Though half the time I want to call it Exit 240!)

[Scott5114]

I can do the math in my head and I still like sequential numbering.  As for distance, that's what the Atlas is for.  And, I have a hard time remembering mileage-based exit numbers so if I have to open up an atlas it is only slightly easier to use the mile markers than add it up. 

But, mainly, having grown up in PA, that's what I was used to.  I can recite from memory nearly every road that is at each exit on I-80 and the PA Turnpike Mainline and Northeast Extension under the sequential system, but I can't remember what their mileage numbers are.

Of course, that's just personal preference. I would much rather have the distance handy out the window than have to try and glance at the atlas while driving and estimate the distance based on that. Jake is very good at estimating distances from an atlas; I am not! I also find looking for a milepost and subtracting the distances to be a very satisfying way to spend the time on the road while on a long trip.

Regarding the numbers, it can be just as easy to memorize mileage-based exits. Oklahoma has always had them; I-35 exits in OK: Exit 1, US-77 and WinStar Casino, Exit 3: OK-153 for Thackerville, Exit 72: OK-19, Pauls Valley/Maysville, Exit 92: Purcell south, Exit 95: Purcell north, Exit 104: OK-74, Goldsby/Washington, Exit 109: OK-9, Chickasha and Riverwind Casino, Exit 174: OK-51, Stillwater/Hennessey, and so forth. And Exit 127 in KS is where I-35 splits off from the Kansas Turnpike.

[mightyace]

Regarding the numbers, it can be just as easy to memorize mileage-based exits. Oklahoma has always had them; I-35 exits in OK: Exit 1, US-77 and WinStar Casino, Exit 3: OK-153 for Thackerville, Exit 72: OK-19, Pauls Valley/Maysville, Exit 92: Purcell south, Exit 95: Purcell north, Exit 104: OK-74, Goldsby/Washington, Exit 109: OK-9, Chickasha and Riverwind Casino, Exit 174: OK-51, Stillwater/Hennessey, and so forth. And Exit 127 in KS is where I-35 splits off from the Kansas Turnpike.

True, I do have a bit of easier time if there's never been a cutover.  Of course, I've had 30 plus year to memorize PA's sequential numbers while mileage based there has been around less than 10 IIRC

[OracleUsr]

Having lived in GA for a few years as a co-op student in the 90's, I never got used to the sequential numbering.  To get the distance to your exit in a sequential state, you have to know the mile numbers at each exit then do the subtraction.

All I have to know in NC/SC are the exit numbers and I'm there.  Plus, you don't have these Exit xxxA exits in the middle because no one thought they'd build an exit there.

I remember in PA one time I saw a sign on the side of the road that said "NO EXIT 7 WE DON'T WANT IT".  This was before their conversion to the distance numbering.

I also remember seeing a Holiday Inn sign south of Chambersburg that referenced Exit 80E in Winchester, VA (instead of 313A--US 50E/US 17S/US 522S).

[Mr_Northside]

PennDOT didn't do mileage-based exit numbers on their US and PA designated expressways.

I'll chalk that up to some PennDOT idiocy. (Or, more likely, cheapness?) 

Most of the non-interstate expressways in PA don't seem to have exit numbers, but to not change the ones that do (I'm mostly thinking of PA-28, since it's the example I use the most) while changing the interstate exit numbers is (was) a dumb move.  They should track down a dictionary and look up "consistency".  Either all your exit numbers should be based on mileage, or not. 

[PAHighways]

Most of the non-interstate expressways in PA don't seem to have exit numbers, but to not change the ones that do (I'm mostly thinking of PA-28, since it's the example I use the most) while changing the interstate exit numbers is (was) a dumb move.  They should track down a dictionary and look up "consistency".  Either all your exit numbers should be based on mileage, or not.

Putting exit numbers on non-Interstate expressways is something only District 4 and District 11 have done, and doesn't appear to be a mandate from Harrisburg.

[yakra]

And all of Maine is now mile-based (it used to all be sequential).

Not quite.
All of I-95 (which includes all of the Maine Turnpike) is mile-based.
I-295 is mile-based from exit 11 north. South of there, they were left as is, as exit 10 neatly lines up to milepost 10ish, with 11 right smack after it at MP 11ish. I guess they decided going all alphabet-soup south of MP 8 would be too much public confusion for only marginal benefit. Close enough!
Off the top of my head, for a little perspective on distance: MP 5 is 2/3 of the way from exit 5 to exit 6, MP 6 is within the exit 7 interchange, and MP 8 is N of exit 9.
Interstates 195 & 395 kept their exit numbers:
I-195 only had exits 1 and 2. Exit 2 is at MP 1.55; 1 at <1. Round up; it works out nicely.
I-395 is 5 mi long, ending at exit 6. Exit 1 for I-95 is @~ MP 0. Close enough. Round up. Fudge it a la 295 if necessary.

[yakra]

All of I-95 (which includes all of the Maine Turnpike) is mile-based.

Not quite! I forgot exit 3 stayed the same! A quick look at google maps puts it just a touch south of MP 2. Given the layout of this interchange, IMO it's a good candidate for being part of a 2A/B or 2A/B/C setup.

[wytout]

I think that is changing...if i recfall rightly, i think the Feds are putting heat oin the States to adopt mileage exit numberings....NY i heard is going to start that fairly soon....Connecticut might be a bit more difficult given how tightly packed the exits are, esp on I-95....and it will confuse a lot of drivers to change

CT might also be difficult because it's tough to get them to change anything.... ever... period. 

[vdeane]

CT might have too many exits for distance based to work well.  Like how NYSDOT rejected distance based exits in the 70s because of NYC.

[ctsignguy]

CT might also be difficult because it's tough to get them to change anything.... ever... period. 

When i talked to Jeff this past week, he told me that while it makes sense for a lot of States to do mileage=based number sequences, in Connecticut, it would be a nightmare to sort it all out on I-95 from the state line to East Haven, and I-84/91 around Hartford...the only route it would make sense would be for I-395....except it carries the old Turnpike exit numbers and as with I-95, people are loathe to change what they have been comfy with for a half-century...

Afterall, trying to get around downtown Cincinnati with their countless Exit 1s on both I-71 and I-75 can be a nightmare for those NOT familiar with the area, so i can certainly see his viewpoint!!

[Mergingtraffic]

I think that is changing...if i recfall rightly, i think the Feds are putting heat oin the States to adopt mileage exit numberings....NY i heard is going to start that fairly soon....Connecticut might be a bit more difficult given how tightly packed the exits are, esp on I-95....and it will confuse a lot of drivers to change

CT might also be difficult because it's tough to get them to change anything.... ever... period. 

I could agree with that...CT still doesn't like to use operational lanes at expressway interchanges, although that is beginning to chage with several projects, also CT doesn't like to use 2-way laft-turn lanes.  Also, with their recent I-84 widening project, they kept a left exit in there! Exit 29 on I-84 WB is still a left! Although they say $$ was the issue.  If that was AL,  it STILL would've been removed! 

[hbelkins]

CT might have too many exits for distance based to work well.  Like how NYSDOT rejected distance based exits in the 70s because of NYC.

Letter suffixes seem to work OK in Cincinnati, and also in Kansas City.

[Duke87]

Letter suffixes seem to work OK in Cincinnati, and also in Kansas City.

They work fine in NYC, too.

I-95 has exits 1A, 1B, 1C, 2A, 2B, 3, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, 7C, 8A, 8B, and 8C. So what? It's then after that when it switches to sequential and you have exits 9 and 10 practically on top of each other that it seems odd.

As for sorting it out... it's not difficult. Take the mileage and round it off. There's your exit number. Letter suffix in order if necessary. Hell, Wikipedia can give you the necessary information.

[vdeane]

NYSDOT actually launched a project to convert I-95 to fully sequential exit numbering.  As far as I know, exits 1A-C got partially converted to 1, 2, and 3, and then the whole thing just stalled out and hasn't changed since.  The testing they did in the 70s was just I-95 and I-890 (the latter of which has the same numbers regardless of sequential or distance based numbering, with the exception of exit 4C; even with the addition of NY 890, it remains entirely distance based).

In NY, exit suffixes denote two ramps that are related somehow (typically by going to the same road in the same interchange), though they are also used when exits are added between two existing exits.  I can see why NYSDOT would want to avoid having too many suffixes (not that I necessarily agree with it); it is worth noting that NYC has dictated NY politics since time immoral.

[Mergingtraffic]

Unlike most people in this thread, I like sequential numbering and hate distance-based numbering.  I find it too difficult to figure out the distance between exits in my head.  The only time I do like distance-based numbering is when I'm going through an entire state heading west or south.  It tells me the remaining distance on the road in that state.

Fortunately for me, New York has sequential numbering! :partyhat:

I agree, I like sequential exit numbering as well....most motorists don't notice mileage in my opinion.  But, they do expect exit 2 to be before exit 3.  I don't understand what is wrong with sequential numbering...it seems like common sense to me.