mileposts and exit numbers in opposite directions

[NE2]

How common is this? I-581 has mileposts from south to north, but exits are (correctly) numbered north to south, starting at I-81. (They appear to be sequential, but it barely makes a difference on this route.)

Common sense says that this is not the "reference location sign exit numbering method", but that's not explicitly defined (in particular, nowhere can I find that exit numbers must match mileposts, though this is implied by the name). The section on mileposts also doesn't say anywhere that mileposts on a spur must start from the mainline. So while the intent is obvious - that mileposts should start at I-81 - the MUTCD at best goes about this indirectly, by saying separately that mileposts must exist and that exit numbers must begin at I-81, and independently implies (by using the name "reference location sign exit numbering method") that the two should match.

[SignGeek101]

ON 417 is numbered from East to West. Not sure why.

[NE2]

ON 417 is numbered from East to West. Not sure why.

Because the km posts increase from east to west

Supposedly it's because the east end is fixed but the west end keeps moving west. But I was looking for roads where the distance posts and exit numbers go in opposite directions to each other, not both opposite an arbitrary standard that may not even be strictly followed in Canada.

[Brandon]

I-90's mileposts on the Chicago Skyway increase from Indiana to the Ryan Expy.  There are no exit numbers.

I-180's (IL) mileposts increase from I-80 south toward Hennepin.  The interstate is signed north-south, and again, there are no exit numbers.

When signed, I-80 will have a short stretch of exit numbers (mileposts are already there) that increase from east to west while it is concurrent with I-294 on the Tri-State Twy.

ON-417 increases from east to west as that's how Ontario is building the freeway.  Otherwise, with each new extension, the MTO would have to resign the entire freeway.

[hotdogPi]

Northern end of MA 128. The exit numbers decrease while going "north" (really east), while the mile markers increase.

[TEG24601]

I-90's mileposts on the Chicago Skyway increase from Indiana to the Ryan Expy.  There are no exit numbers.

I-180's (IL) mileposts increase from I-80 south toward Hennepin.  The interstate is signed north-south, and again, there are no exit numbers.

When signed, I-80 will have a short stretch of exit numbers (mileposts are already there) that increase from east to west while it is concurrent with I-294 on the Tri-State Twy.

ON-417 increases from east to west as that's how Ontario is building the freeway.  Otherwise, with each new extension, the MTO would have to resign the entire freeway.

They could just figure out where the west end will be, and set mileage/kilometredge from there.  Oregon did that.  It bit them in the ass a few times as freeways were cancelled, so they now have "Odometer Correction" signs, with I-84 being the biggest issue, given that its run on the Banfield Freeway was eventually going to revert to US 30, and be moved south to the Mt. Hood Freeway.

[vdeane]

ON 417 wouldn't have that issue as it could essentially inherit the km posts of ON 17.  ON 401, on the other hand, does have that problem, and probably will until the DRIC is built (at the very least until the Windsor-Essex Parkway is finished).

[Duke87]

They could just figure out where the west end will be, and set mileage/kilometredge from there.

That's the point here: there is no hard planned west end. As population grows in the future, the freeway may be extended further west as needed. The logical extreme would be the western end of ON 17, but that's well over 1000 km away and I'm sure MTO sees no reason for all the exit numbers on ON 417 to be four digits.

[AsphaltPlanet]

ON 417 wouldn't have that issue as it could essentially inherit the km posts of ON 17.  ON 401, on the other hand, does have that problem, and probably will until the DRIC is built (at the very least until the Windsor-Essex Parkway is finished).

Hwy 401 doesn't really have that problem.  The first exit (#13) is about 13km away from the proposed DRIC.  It's probably not exact, but its close enough.

It doesn't really count, but for a few months a few years ago, the 406 in Ontario had exit numbers posted southwards from the QEW, with mileage markers starting northerly from the southern terminus of the freeway at East Main Street.  The mileage markers were then reversed to coincide with the exit numbers.

[NE2]

Northern end of MA 128. The exit numbers decrease while going "north" (really east), while the mile markers increase.

So far this is the only one that actually counts. Exit numbers have always increased from Gloucester (initially with 1 at the Route 127 rotary? but now 11 is there - why?) but the mileposts are probably more recent.

[roadman]

Northern end of MA 128. The exit numbers decrease while going "north" (really east), while the mile markers increase.

Another good reason to eliminate the pointless and outdated I-95/128 overlap between Canton and Peabody.  If MassDOT did this, then 128 in Peabody could start at Mile 0.0 and be properly signed as an East-West roadway.  This would also make it far less confusing when MassDOT implements the mile-post exit numbering conversion beginning in 2016.

[Mapmikey]

For a time the capital beltway did this on the west side in Virginia.

Mile markers were changed to the current dynamic (44 at the American Legion Br to 57 at the I-95/395 jct) but the exits were still numbered 1 at US 1 Alexandria to 14 at the GW Pkwy by the Amer Legion Br.

I cannot find a posting I thought I made to misc.transport.road about how long this dynamic was in place until the exit numbers were changed to match the mile markers.

Mapmikey

[PHLBOS]

Northern end of MA 128. The exit numbers decrease while going "north" (really east), while the mile markers increase.

So far this is the only one that actually counts. Exit numbers have always increased from Gloucester (initially with 1 at the Route 127 rotary? but now 11 is there - why?) but the mileposts are probably more recent.

The mileposts are indeed more recent.  Back in the mid-70s, I do remember seeing higher numbered mileposts along the Beverly stretch of 128 as a kid and they increased while heading towards Gloucester; the numbering likely originated from Braintree back then as many here know (the I-95/93 concurrencies were still fairly new & recent).

Actually, the northeasternmost numbered exit for 128 is Exit 9 at the intersection w/MA 127A (128's terminus).

Steve Anderson on his BostonRoads page (scroll to the bottom) gives one reason for 128 starting at Exit 9; the road was to be extended furhter into Cape Ann.  Still, I don't see how there would've been 8 other interchanges in the Gloucester/Rockport area.  A definite DPW exit number fail IMHO.

[NE2]

I wonder if they decided it would be easiest to simply add 10 to the lowest numbers (similar to I-69 in Indiana adding 100).

[vdeane]

ON 417 wouldn't have that issue as it could essentially inherit the km posts of ON 17.  ON 401, on the other hand, does have that problem, and probably will until the DRIC is built (at the very least until the Windsor-Essex Parkway is finished).

Hwy 401 doesn't really have that problem.  The first exit (#13) is about 13km away from the proposed DRIC.  It's probably not exact, but its close enough.

As I said, until the DRIC is built.  Right now the exit numbers start at 13, at it looked for a long time like the situation would be permanent.  Even once the Windsor-Essex Parkway is built, the mileage still won't start at 0 until the DRIC is built, which might not be for a few decades as even the I-95/Pennsylvania Turnpike interchange is moving faster at this point.

[NE2]

"That problem" was never defined, but beginning with 13 was never mentioned as a problem.

[vdeane]

"That problem" was never defined, but beginning with 13 was never mentioned as a problem.

Technically it was defined in the post above where I first mentioned it.  I'll often omit a quote if I'm responding to the post immediately above mine - never though someone might be confused by that.

[AsphaltPlanet]

^ Yeah, I probably didn't read the post carefully enough.

Though it's never struck me that having the 401's mileage markers start from the Ambassador Bridge would constitute a problem, but I know what you're saying.

[NE2]

"That problem" was never defined, but beginning with 13 was never mentioned as a problem.

Technically it was defined in the post above where I first mentioned it.  I'll often omit a quote if I'm responding to the post immediately above mine - never though someone might be confused by that.

So the problem would be distance equations? Only if they put 0 and not (13 minus the length of the extension) at the bridge.

[PHLBOS]

I wonder if they decided it would be easiest to simply add 10 to the lowest numbers (similar to I-69 in Indiana adding 100).

IIRC, the original exit numbers at the full-cloverleaf interchange ramps (based from an old USGS Salem, MA quadsheet that you posted some time back) were actually 2 separate exit numbers as opposed to Exit XXN-S (or XXE-W) so adding 10 for simplicity reasons would only have been applicable as far as the MA 1A interchange (current Exit 20A-B) in Beverly.

[NE2]

Indeed, but it would have made exits 1-9 easier.

[vdeane]

"That problem" was never defined, but beginning with 13 was never mentioned as a problem.

Technically it was defined in the post above where I first mentioned it.  I'll often omit a quote if I'm responding to the post immediately above mine - never though someone might be confused by that.

So the problem would be distance equations? Only if they put 0 and not (13 minus the length of the extension) at the bridge.

I prefer roads that start at 0.  It's 12 km to the border from ON 401's original endpoint (9.5 to its hopefully temporary endpoint at Ojibway Parkway).  It's 15 to I-75.

[jwolfer]

^ Yeah, I probably didn't read the post carefully enough.

Though it's never struck me that having the 401's mileage markers start from the Ambassador Bridge would constitute a problem, but I know what you're saying.

I could be a dick and say 401has kilometer markers

[kurumi]

I-691 mileposts increase to the west (highway log) while exit numbers increase to the east.

Connecticut highway mileposts always increase to the north or the east with the exception of:
* one-way roads going south or west
* I-691

This could be due to the order in which segments of I-691 were constructed:
* US 5 to end of freeway, Middlefield, 1966
* CT 322 to US 5 (to the west of 1st segment), 1971
* I-84 to CT 322 (to the west of 2nd segment), 1987
The western segments got funded later as well.

I don't know if mileposts are actually posted on 691 --- giving observant drivers an uncanny sense that something is wrong.

And what happens when I-691 goes to milepost-based exit numbering? A doc I have from a DOT contact a few years ago (sort of "if we had to go to mileage-based, here's what the next exit numbers would be") shows that the mileposts would stay, and the new exit numbers would switch to increase westbound.

[NE2]

And what happens when I-691 goes to milepost-based exit numbering? A doc I have from a DOT contact a few years ago (sort of "if we had to go to mileage-based, here's what the next exit numbers would be") shows that the mileposts would stay, and the new exit numbers would switch to increase westbound.

Which is not necessarily incorrect. If it's considered circumferential, numbers increase clockwise. If it's considered a spur, numbers increase from I-91.