(Exit 3 to Northern terminus, exits onto I-5 south; MP 2.76-3.53, 0.77 miles)
Interstate 405, the Stadium Freeway, was created under the National System of Interstate and Defense Highways Act of 1956 along with several other freeways in Oregon. However, the first segment (from the Marquam Bridge to Everett Street) were not built until the 1960's, along with other projects such as I-5's Marquam Bridge and the Vista Ridge Tunnel of US-26. The remaining section (Everett Street over the Fremont Bridge to the I-5 reconnect) was finished in 1973. Temporary ramps were placed to and from Irving St. while the rest of the freeway was being constructed.
The Stadium Freeway wasn't very well received. The six-to-eight lane highway was carved into the ground of Portland; much of it is 10-15 feet below the surrounding landscape and buildings. Homes, business, and churches were relocated to accomodate I-405. However, today I-405 isn't a despised freeway and in fact is a vital part of the Portland experience.
Any south Portlander that needs to take I-5 through Portland to points north usually takes I-405. Why? Because I-5 is only 2 lanes each way between I-84 and the northern I-405 junction, which causes for real bad traffic headaches when I-84 west bound traffic dumps onto I-5 northbound. Meanwhile, I-405 is three-plus lanes each way for all of its 3½ miles, and while it is heavily used, doesn't need to contend with I-84 traffic from across the river; it only need deal with US-26 traffic, which is usually more concerned with heading through Portland than heading to Seattle or Salem. Besides, though signs have been replaced, most are from around the time the freeway was built (examples: Check out street identification signs on overpasses and the gore sign at Exit 2B Northbound...man that's old lettering).
Still, I-405 is not without its critics today. Portland's crazy-yet-lesser of two evils mayor Vera Katz put forth an idea a few years ago to cover up I-405 for the first 2-3 miles to rebuild homes and businesses. Though it could work in theory (I was actually one of it's lone supporters), it would cost too much to do, and the idea was scrapped. Another proposal was to re-route I-5 through Portland (the length of I-5 between I-405's termini and I-405's length is nearly identical), take out the Marquam Bridge, turn the northern bridge approach into a Portland Saturday Market-like shopping center, and extend I-84 to where I-5 and I-405 meet north of Portland. Besides the idea being costly and slightly insane, that would mean extra traveling time for those living in south Portland who wanted to, say, go to the airport, not to mention renumbering I-5 and I-84's exits (I-84 has a milepost resynchronization 7 miles outside of Portland, so not all exits would be affected) and creating mass confusion ("Where is I-405? It's on the map.", etc.). That plan was scrapped as well, thankfully. And ODOT is planning to widen I-5 between I-84 and I-405 sometime in the next ten years. Yay...
Also interesting to note, there was supposed to be an I-505 spurring off of I-405 at Exit 3 (present day US-30 Yeon Ave. exit). Click the I-505 link above to find out why it wasn't built.
EXIT 1A: This exit is only accessible by the onramp to I-405 North from I-5 North. After exiting, you travel for about ¼-½ miles on a short freeway known as Harbor Drive. This was once the route of the long-since decommissioned US-99W through Portland, and the route itself was a freeway along Portland's waterfront called the Harbor Freeway. In the 1970's, freeways were considered bad, and in a drive spearheaded by former Oregon governor Tom McCall, cancelled several pending freeway projects around Portland, Salem, and Eugene. In addition, he removed the Harbor Freeway and created Waterfront Park in its wake (later named after the good governor). US-99W was realigned to Front Ave., and all that remained of the Harbor Freeway is the little nub that still exists today. It has one unnumbered exit to Sheridan St. (where the exit sign comes before the BGS indicating what exit it's for...not ODOT's style), but that's it. Both I-405 north and south share a small portion (three-tenths of a mile or so) with the now-defunct Harbor Freeway, but only I-405 north can exit to it.
EXITS (1B) AND (1A): These are what I call the ramps for I-5 North and I-5 south respectively on I-405 southbound. Oregon doesn't number its Interstates' termini (not even for grand-daddy I-84), so the progression of numbers south on 405 is 3, 2B, 2A, 1D, 1C, and the split. I logically numbered them exits 1B and 1A, assuming that the exit for I-5 north is the only one actually exiting from I-405. After the split but before reaching its dad, I-405 merges with a little of the remnants of the Harbor Freeway , which, interestingly enough, sports a MILE 300 sign before it even touches I-5 (probably a remnant of US-99W's routing, see above).
EXIT 1C: Just past the offramp to Exit 1C on the right-hand side of I-405 north, you would've found I-405's sole mileage marker, a little MILE 1 sign. But in 2003, ODOT must've remeasured I-405, because they not only moved the mileage marker up to Exit 1D, but also added a marker southbound as well as one MILE 2 marker in each direction (northbound just past Exit 2B and southbound just past Exit 2A). No MILE 3 markers exist yet, but if they would, they'd be somewhere near the center of the Fremont bridge.
EXIT 1D: The signs are labeled US-26, but it's really for US-26 westbound; the signs fail to mention that. US-26 eastbound's ramp from I-405 North comes in the form of the ramp to 12th Street. (I-405 South's ramp to US-26 East is Exit 1C, but it actually doesn't directly link to US-26 east...one must navigate surface streets to link up there.) During the summer of 2003, southbound Exit 1D was widened to carry two lanes to US-26 instead of one. I may have before pictures, but I know I have after...they'll be up soon.
EXIT 2A: According to mileage figures, northbound this should be Exit 1E.
EXIT 2B: Affixed on an overpass (Burnside St.) is the last remaining old-style exit gore signs in existance (the other one I knew of, on OR-217 North at Walker Rd., was replaced by an Exit 1 sign around 2000). The spacing of the letters E X I T on the sign, its seafoam color and button copy letters, numbers, and arrow all allow me to conclude that this sign has been there since around this freeway's opening. You see similar types of fades on exit tabs of I-5, I-405, and older parts of I-84. Also, according to mileage figures, northbound this should either be Exit 1F or Exit 2A.
EXIT 3: This should be Exit 3A for northbound travelers...if only Oregon were consistent in numbering exits on highway termini...shame shame. As if I-405 north hasn't been getting enough of the attention, Exit 3 north is the second of I-405's three left exits along its route, the first being Exit 1A and the third being an unnumbered exit for "US-30 East The Dalles" (technically I-405 south has none because I-405 splits at its southern terminus). This exit from either direction takes you onto another short freeway (US-30 West, Yeon Ave.) There's a history behind this one as well, but you'll have to click here to find out about it.
EXITS (3B) AND (3C): The exits for "US-30 East The Dalles" and Kerby Ave. should be labeled Exit 3B and 3C respectively, but for some reason interstate termini do not have their exits labeled in Oregon. There isn't even so much as an "Exit 0" anywhere. Anyway, the bizarre thing about Exit 3B is that it's labeled "US-30 East The Dalles". While I originally thought it was stupid to not sign any other major route the ramp led to, such as I-5 South or I-84, my guess is that this signage is a remnant of I-84's original proposed routing along the Mt. Hood Freeway as I-80N. If the Mt. Hood Freeway would've ever been built, I-84's current routing along the Banfield Expressway would've been shifted to the Mt. Hood, thus removing the Banfield from the Interstate system, leaving US-30 on that freeway. Because that was a possibility in 1973 when the Fremont Bridge opened, the original signs probably showed US-30 by itself in anticipation of the Mt. Hood Freeway's completion. The project was eventually cancelled in favor of light rail, but the signs never changed.
Also, on the approach ramps to and from I-405 there are ghost ramps with gates to another cancelled freeway that would've led to the west side of the airport, the Rose City Freeway. The part of this cancelled freeway that remains is the nice little parkway off of the Kerby Ave. right exit that leads toward Emanuel Hospital. The parkway going to I-405 south has no direct I-5 connection. Signs at the northern end of the parkway announce that the parkway goes to the "Fremont Bridge" with no explicit reference to I-405.
If you decide not to take I-5 South or Kerby Ave., you're dumped back onto I-5 northbound. Seattle here I come!