Placement of the zero mile marker on beltways

[KCRoadFan]

For me, this is post number 435 - the same number as that of the beltway that encircles my city of Kansas City - so I figured that I might as well make it a post on beltways. More specifically, I was wanting to remark that on many beltways, the zero mile marker is in the same place, around the middle of the south leg - at least, that's the case with the beltways that I've driven on, such as the aforementioned I-435, as well as I-465 in Indianapolis, I-270 in Columbus, OH, and I-494/694 in the Twin Cities in Minnesota - in addition to the most famous beltway of all, namely I-495 in the DC area (although I should note that the exit numbers on that one run counterclockwise, as opposed to clockwise like the other ones that I've mentioned).

Anyway, is that convention - having mile zero along the south side - true of all beltways in the country? In addition, is there any particular reason as to why it might be so? I ask this because on the face of a clock, the "zero point" (namely, 12 o'clock) is on the top (equivalent to the north side on the map) as opposed to the bottom (the south side) - also, on a compass, zero degrees is north.

[SkyPesos]

Looking at some other full beltways you didn't mention, it seems to be the case. I-275 start at the I-71/75 interchange. I-285 start at the southern I-85 interchange. I-485 start at the southern I-77 interchange. In TX, I-410 starts at the southern I-35 interchange, and I-610 starts at the TX 288 interchange. I-695 in (almost) Baltimore's zero marker is somewhere on the bridge in the SE corner. All of them mentioned here also go clockwise. List goes on.

I-494/694 is an interesting case. Personally, I think that both should have the zero point at their respective northwestern interchange with I-94 (and remove the beltway mileage from the 94/694 concurrency), as imo they are two separate interstates serving separate functions, and thus should also have separate mileage.

[ilpt4u]

St Louis's I-270 and I-255 don't have unified mileage as a single beltway. I-255 has continuous mileage cross the MS River, whereas I-270 resets at the MS River. That said, I-270/MO and I-255 MM Zero is at the I-55/MO interchange, the southern point of the beltway

[chrisdiaz]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

[ilpt4u]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

[roadman65]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Some states have their own rules. Florida is one but allow I-275 and I-75 to remain.

Virginia is another hence VA 895 and VA 195 in Richmond. Also former VA 44 instead of I-264 being signed there originally.

[Scott5114]

Anyway, is that convention - having mile zero along the south side - true of all beltways in the country? In addition, is there any particular reason as to why it might be so? I ask this because on the face of a clock, the "zero point" (namely, 12 o'clock) is on the top (equivalent to the north side on the map) as opposed to the bottom (the south side) - also, on a compass, zero degrees is north.

It's MUTCD standard:

For circumferential routes, interchange numbering shall be in a clockwise direction. The numbering shall begin with the first interchange west of the south end of an imaginary north-south line bisecting the circumferential route, at a radial freeway or other Interstate route, or some other conspicuous landmark in the circumferential route near a south polar location (see Figure 2E-19).

As for why they chose the southernmost point as the reset point, my guess is it's for consistency with non-beltway routes having their zero milepost at the southern terminus.

[Rothman]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Perhaps you should ask PA about I-80...

[LilianaUwU]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Perhaps you should ask PA about I-80...

Or I-76, for that matter.

[jeffandnicole]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Perhaps you should ask PA about I-80...

Well, that's a different case because of what rules there were regarding tolling I-80, PA ignored, and thus never got the chance to toll the highway.

[davewiecking]

For me, this is post number 435 - the same number as that of the beltway that encircles my city of Kansas City - so I figured that I might as well make it a post on beltways. More specifically, I was wanting to remark that on many beltways, the zero mile marker is in the same place, around the middle of the south leg - at least, that's the case with the beltways that I've driven on, such as the aforementioned I-435, as well as I-465 in Indianapolis, I-270 in Columbus, OH, and I-494/694 in the Twin Cities in Minnesota - in addition to the most famous beltway of all, namely I-495 in the DC area (although I should note that the exit numbers on that one run counterclockwise, as opposed to clockwise like the other ones that I've mentioned).

fyi: DC Beltway was originally numbered clockwise from the Springfield interchange. When the eastern portion was renumbered from I-495 to I-95, the Beltway exit numbers were reordered to follow the I-95 numbering (exits numbers in the 170's), which reset at the VA/MD line. The exit numbering both west of College Park along the Beltway, and north of College Park along I-95, both continued this numbering sequence.

[1995hoo]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

Another possible reason is that the first segment of I-540 to open back in the mid-1990s ran from I-40 to US-70. Back then there wasn't a lot of reason to use the road and it was where you'd go to see how fast your car could go.

[roadman65]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Perhaps you should ask PA about I-80...

Or I-76, for that matter.

Or I-90 from Chicago to Boston.

[US20IL64]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Also, 294, 88, 94, 80 and 90,

NJ TPK I-95 and NY Thru-way I-90, too.

[ilpt4u]

Raleigh's I-540 has its mileage reset at the western interchange with I-40. This is most likely because only the northern portion will be designated as an interstate due to the southern portion being tolled.

There is no rule against tolling an Interstate. Just ask I-355 in Illinois

Also, 294, 88, 94, 80 and 90,

NJ TPK I-95 and NY Thru-way I-90, too.

My 355 comment was more because it was constructed and opened as a tolled Interstate - the other examples here in IL and elsewhere were built before they received the I-shield

[hbelkins]

...and my experience is that the exit signifying the mile marker reset is usually for the high number, not the low number. Otherwise I-275's exit number for the ramps to I-71/I-75, or KY 4's exit number for US 27, would be 0.

[jmacswimmer]

I-695 in (almost) Baltimore's zero marker is somewhere on the bridge in the SE corner.

To expand on this one a little bit: 695 is a little wonky in that the exit numbers reset at the Key Bridge, but mile 0 is on the Curtis Creek drawbridge (and FWIW, 695 is in fact just inside the Baltimore city limits here it crosses over from Anne Arundel County just west of the actual drawspan).

As a result, exit 1 (which is between Curtis Creek & the Key Bridge) is actually on the wrong side of the zero point, falling at mile 50.

[ran4sh]

For a short period from 1999 to 2004, GA 10 Loop (the beltway for Athens) had clockwise-numbered exits, and then in 2004 was changed to the current numbering which goes counterclockwise.

In either system, milepost 1 was assigned to the GA 316 (US 29-US 78-GA 316) west/south exit. Milepost 0 was a mile before milepost 1 in the increasing direction.

This does mean that GA 10 Loop had milepost exit numbers before most of the Interstates in GA did (10 Loop got exit numbers in 1999 and the Interstates were converted to milepost numbers in 2000).

Before 1999, GA 10 Loop had no exit numbers at all, and had milepost 0 at the end of the northeast "stub" of the route where it intersected Old Hull Rd (with the mileposts increasing clockwise). Before about 1988, it wasn't even a complete beltway so it most likely would have been mileposted according to the overlapping routes and not as a route by itself.

[KCRoadFan]

Looking at some other full beltways you didn't mention, it seems to be the case. I-275 start at the I-71/75 interchange. I-285 start at the southern I-85 interchange. I-485 start at the southern I-77 interchange. In TX, I-410 starts at the southern I-35 interchange, and I-610 starts at the TX 288 interchange. I-695 in (almost) Baltimore's zero marker is somewhere on the bridge in the SE corner. All of them mentioned here also go clockwise. List goes on.

I-494/694 is an interesting case. Personally, I think that both should have the zero point at their respective northwestern interchange with I-94 (and remove the beltway mileage from the 94/694 concurrency), as imo they are two separate interstates serving separate functions, and thus should also have separate mileage.

Looks like this calls for an exit list!

I-94
216: I-494 South
217: County 61/Hemlock Ln (Current Exit 28)
218A-B: US 169 (Current Exit 29A-B)
219: Boone Ave (Current Exit 30)
220: County 81 (Current Exit 31)
222: County 152/Brooklyn Blvd (Current Exit 33)
223: Shingle Creek Pkwy (Current Exit 34)
224A (EB only): MN 100 South (Current Exit 35A)
224B (EB only): I-694 East (Current Exit 35B is for I-94 East; in this situation, the exit tab would be relocated)

I-494
1A-B: I-94 (Current Exit 27)
2: County 10/Bass Lake Rd (Current Exit 26)
5: County 9/Rockford Rd (Current Exit 23)
6: MN 55 (Current Exit 22)
7: County 6 (Current Exit 21)
8: Carlson Pkwy (Current Exit 20)
9A: US 12 West (Current Exit 19B)
9B: I-394/US 12 East (Current Exit 19A)
11: County 5/Minnetonka Blvd (Current Exit 17)
12A-B: MN 7 (Current Exit 16A-B)
15: MN 62/County 62 (Current Exit 13)
16 (SB only): County 39/Valley View Rd (Current Exit 12)
17A: US 212/MN 5 West (Current Exit 11C)
17B: US 212 East (Current Exit 11B)
17C (WB only): County 61/Flying Cloud Dr/Prairie Center Dr (Current Exit 11A)
18A (EB only): Washington Ave (Current Exit 10B)
18B: US 169 (Current Exit 10A)
20: County 28/E Bush Lake Rd (Current Exit 8)
21A: County 34/Normandale Blvd (Current Exit 7B)
21B: MN 100 (Current Exit 7A)
22A: County 17/France Ave (Current Exit 6B)
22B: County 32/Penn Ave (Current Exit 6A)
23A-B: I-35W (Current Exit 5A-B)
24A: Lyndale Ave (Current Exit 4B)
24B: County 52/Nicollet Ave (Current Exit 4A)
25: County 35/Portland Ave (Current Exit 3)
26A-B: MN 77/Cedar Ave (Current Exit 2B-C)
26C: County 1/24th Ave (Current Exit 2A)
27A: 34th Ave (Current Exit 1B)
27B: MN 5 East (Current Exit 1A)
30: County 31/Pilot Knob Rd (Current Exit 71)
31A-B: I-35E (Current Exit 70A-B)
32: MN 149 TO MN 55/Dodd Rd (Current Exit 69)
34: MN 3/MN 62/Robert St (Current Exit 67)
35: US 52 (Current Exit 66)
36: 5th Ave/7th Ave (Current Exit 65)
37A: MN 156/County 56/Concord St (Current Exit 64B)
37B: Hardman Ave (Current Exit 64A)
38A: County 38/Maxwell Ave (Current Exit 63C)
38B-C: US 10/US 61 (Current Exit 63A-B)
41: County 25/Lake Rd (Current Exit 60)
42: County 16/Valley Creek Rd (Current Exit 59)
43A: Tamarack Rd (Current Exit 58C)
43B-C (NB only; SB uses I-694 numbers): I-94 (Current Exit 58A-B)

Note: Because this list reverses the direction of the exit numbers on I-494, the order of letter suffixes in cloverleaf interchanges should be reversed when translating from current exit numbers to new numbers, as far as assigning exit numbers to each ramp.

I-694
1A (WB only): I-94 East (Current Exit 35B; WB I-694 merges into WB I-94)
1B: MN 252 (Current Exit 35C)
2: County 1/East River Rd (Current Exit 36)
3: MN 47/University Ave (Current Exit 37)
4: MN 65/Central Ave (Current Exit 38)
5: County 44/Silver Lake Rd (Current Exit 39)
6: County 45/10th St (Current Exit 40)
7A-B: I-35W (Current Exit 41A-B)
8A (WB only): US 10 West (Current Exit 42A)
8B: MN 51/Snelling Ave (Current Exit 42B)
8C: County 51/Lexington Ave (Current Exit 42C)
9: County 52/Victoria St (Current Exit 43)
11: County 49/Rice St (Current Exit 45)
12: I-35E South/US 10 East (Current Exit 46)
13: I-35E North (Current Exit 47)
14: US 61 (Current Exit 48)
16: County 65/White Bear Ave (Current Exit 50)
17: MN 120/Century Ave (Current Exit 51)
18A-B: MN 36 (Current Exit 52A-B)
21: County 14/34th St N (Current Exit 55)
23: County 10/10th St N (Current Exit 57)
24A-B (SB only; NB uses I-494 numbers): I-94 (Current Exit 58A-B)

Well - that completes the Great Exit Renumbering of the Twin Cities beltway. Anyway, do my exit numbers seem right?

[TheHighwayMan3561]

I-494/694 is an interesting case. Personally, I think that both should have the zero point at their respective northwestern interchange with I-94 (and remove the beltway mileage from the 94/694 concurrency), as imo they are two separate interstates serving separate functions, and thus should also have separate mileage.

Not refuting your point, but that sounds like it might be confusing to give three different sets of exit numbers to one stretch of road.