Regional Boards > Northwest

Oregon Z mile markers

<< < (3/3)

roadman65:
Also the mileposts in Oregon are in reverse along US 101 as they start at the Astoria- Megler Bridge and go up to the California line.  Ditto for US 199 as they progress to California from OR 99 in Grants Pass and US 30 is even more odd. It starts from Portland to the foot of the Astoria- Megler Bridge.

Bickendan:
I-5, US 30, OR 35, I-205, and I-405 are the exceptions.
0 points are the Columbia River and the Pacific Ocean.

OR 35's is at OR 99W on US 26.

roadman65:
Why is US 30 backwards? Itís zero is in Portland at I-405 and climbs up to Astoria instead of the other way around.

BigManFromAFRICA88:

--- Quote from: Bickendan on July 08, 2021, 03:18:06 PM ---I-5, US 30, OR 35, I-205, and I-405 are the exceptions.
0 points are the Columbia River and the Pacific Ocean.

OR 35's is at OR 99W on US 26.

--- End quote ---
The funny thing is I was going to ask about these reverse mile markers on US 101 and US 30 after a trip up the Oregon coast and into Portland. Jarring as a road geek crossing the California line and seeing a milepost in the 360s haha

JasonOfORoads:

--- Quote from: roadman65 on August 01, 2021, 10:49:04 PM ---Why is US 30 backwards? It’s zero is in Portland at I-405 and climbs up to Astoria instead of the other way around.

--- End quote ---

It's because the two major highways in the 1910s, the Pacific Highway and Columbia River Highway, both based their zero mileposts in Portland when they were originally built. These are still held over today in the mileposts for highways 2, 2W, 1E and 1W (well, before a lot of it got transferred back to Portland). For 1E and 1W, this used to be entered into ODOT's records as "X-mileage" and referenced on straightline charts and other documents as such. For example, MP X1.00 would be one mile north of the zero milepost in Portland to distinguish it from MP 1.00 one mile south of Portland. However, ODOT upgraded their systems sometime in the 2000s to allow for negative milepost values, so MP X1.00 became MP -1.00. ODOT split off 2W from 2 at some point in the mid-1950s; I imagine this was to avoid having a highway on their books with 100 miles of X-mileage, but they kept the original milepost values for ease of recordkeeping.

Navigation

[0] Message Index

[*] Previous page

Go to full version