Negative exit numbers?

[sammi]

I don't exactly know what to do when this happens.



The original expressway starts at 8.5, but the extension goes longer than 8.5 so it pushes exit numbers past 0.

Are there even negative-distance exits anywhere? If so, how are they numbered? If not, how do you think they should be numbered? (Right now I have them as letters, A=-1, C=-3, D=-4.)

[Zeffy]

_Simon posted a theoretical concept like this awhile back:

https://www.aaroads.com/forum/index.php?topic=9071.msg211109#msg211109

[sammi]

_Simon posted a theoretical concept like this awhile back:
https://www.aaroads.com/forum/index.php?topic=9071.msg211109#msg211109

Yeah I've seen that before. I guess I couldn't find it because I was searching for exit numbers and not mile markers.
This would make a great addition to my personal MUTCD.

[Alps]

The Atlantic City Expressway Brigantine Connector uses lettered exits. In a sense, it's an extension past 0 of the ACE, but in another sense, it's its own roadway.

Fla's Turnpike has the Homestead Extension, but the exit numbering already takes it into account (after FL switched over from sequential to mile-based). If it becomes extended further, you'd run into this territory.

[oscar]

Talking milemarkers rather than exit numbers, Alaska DOT passed up an opportunity to use negative mileposts when AK 4 was extended about four miles west to the new Valdez townsite (relocated after the 1964 Good Friday earthquake/tsunami), but mile 0 remains at the turnoff to the old Valdez townsite.  The AK 4 extension was left un-mileposted, but negative (or reverse order) mileposts could've been used instead.  Since mileposts are used for addresses in rural Alaska, Alaska DOT generally doesn't recalibrate its mileposts, so moving mile 0 to the new townsite wasn't a good option.

[Brandon]

The Atlantic City Expressway Brigantine Connector uses lettered exits. In a sense, it's an extension past 0 of the ACE, but in another sense, it's its own roadway.

Fla's Turnpike has the Homestead Extension, but the exit numbering already takes it into account (after FL switched over from sequential to mile-based). If it becomes extended further, you'd run into this territory.

Prior to the switch, the Homestead Extension used exit numbers with an "X" suffix, i.e. 1X, 2X, etc.

[NE2]

Prior to the switch, the Homestead Extension used exit numbers with an "X" suffix, i.e. 1X, 2X, etc.

False. The original Turnpike south of the extension uses those.

[bassoon1986]

If Louisiana doesn't feel like replacing 250 miles of mile markers and exit numbers on I-49 when it is totally finished one day, they could create negative exit numbers from Laffy to NO 

[Duke87]

If you're talking about adding exit numbers to a road which doesn't already have them, I see no reason why you can't just add 3.7 to every milepost when determining the appropriate number.

[sammi]

If you're talking about adding exit numbers to a road which doesn't already have them

I'd do that myself if it had no exit numbers. But it does. The highway has km posts from 9 to ~145 at this point, which is actually pretty convenient because the exit number is roughly the distance from the exit to Rizal Park in Manila (from which all PH roads theoretically originate).

The company building the extension is different from the operator of the existing road, so having the latter renumber isn't really an option.

[bulldog1979]

I-270 in Colorado had another set of mileposts added for its extension, so it has two MP0s, but the exit numbers weren't really affected.

[Brandon]

Prior to the switch, the Homestead Extension used exit numbers with an "X" suffix, i.e. 1X, 2X, etc.

False. The original Turnpike south of the extension uses those.

PRIOR TO THE SWITCH, SPUI! 

I have maps showing the "X" suffix on the Homestead Extension from the mid-1980s when the rest of the Turnpike had exits in multiples of 4.

[HurrMark]

The spur from the Golden Glades interchange northward to the extension had X's. The first exit was 0X and the last was 4X. Not sure when/if that changed.. Until the switch to mile marker exits, the extension had no numbered exits...however, mile markers had an X (so mile marker 26X, 31X etc.)

[NE2]

I have maps showing the "X" suffix on the Homestead Extension from the mid-1980s when the rest of the Turnpike had exits in multiples of 4.

I've never seen this on maps. Can you scan one?

[HurrMark]

I have maps showing the "X" suffix on the Homestead Extension from the mid-1980s when the rest of the Turnpike had exits in multiples of 4.

I've never seen this on maps. Can you scan one?

I think the Xs came at the time of the conversion...they were definitely around in the 90s.