Interchange Index
I-210, I-710, and CA 134
Pasadena, CA
Overhead Picture from terraserver-usa.com
Overview: I-210 (the Foothill Freeway), a northern bypass of the Los Angeles metro area, enters this interchange from the north and leaves to the east. The road leading south from here is a stub end of I-710. (For more on I-710, see the description on the stub end below.) From the other highways, this is actually marked as an extended ramp to Del Mar Boulevard and California Boulevard. To the west is CA 134 (the Ventura Freeway), which runs as a freeway through Glendale and Burbank before ending at US 101, which continues westward to the coast of California.
From I-210 eastbound, I-710 will eventually become Exit 25A and CA 134 will be Exit 25B. Westbound, the entire interchange will be Exit 26A, and the exit for Fair Oaks Ave. (the north-south street just east of the interchange) will be Exit 25B. I-210 will be Exit 13B from CA 134. The exits on the I-710 stub are not numbered, nor will they be until (if) the remainder of I-710 is built.
Interchange Description: This is definitely a California-style interchange; no loop ramps, mostly semi-directional ramps, and reasonably well-designed. At its center is a five-level crossing: CA 134 to I-210 westbound on the top, followed by CA 134, Walnut Street in the middle, the I-710 stub at ground level, and the ramp from I-210 westbound to I-710 south in a tunnel below ground. The other two left-turn ramps are handled further from the center; I-710 NB to CA 134 is south of the interchange, and the I-210 eastbound mainline runs under the northwestern quadrant. (It's barely visible in this photo, as much of it is under other overpasses or covered by foliage.) All four right-turn movements are simply basic slip ramps, although most of them cross over or under other local streets.
Local connections are also available in this junction, mostly in the form of partial and full diamond interchanges. The first to observe is right in the middle of the interchange, a half-diamond between I-210 to the north and Walnut Street (the east-west street through the very center). The onramp runs directly from Walnut Street into I-710 north, while the offramp runs from southbound I-710 onto Maple Street (which curves from the south to the east through the interchange). Fair Oaks Ave, which runs north-south just to the east of the interchange, also has a full diamond with CA 134 and I-210 to the east. The western half of the interchange splits from CA 134 and passes over the I-210 and I-710 onramps to join the frontage roads before meeting Fair Oaks Ave., and the eastern half has one standard slip ramp from I-210 WB to the northern frontage road and a left entrance directly from Fair Oaks Ave. into I-210 EB. A few other connections are available; these are discussed below.
I-710 Stub: The overhead view to the right gives a view of the very north end of the ill-fated I-710 extension. Currently, I-710 runs northward from Long Beach, on the coast, to I-10 in Alhambra. At I-10, it has a fairly well-built interchange (which I may also write about someday), and then promptly bottoms out on Valley Boulevard in Alhambra. For years, plans have been made to try to connect this segment with the Pasadena interchange featured here by building an extension through Alhambra and South Pasadena. Alhambra supports the interstate, but South Pasadena is unfortunately opposed to its construction. As a result, the northern end of I-710 is less than a mile of freeway which abruptly ends on city streets, as shown on the right.
The southern end of this stub basically consists of two half-diamond interchanges, both pointing northward. The first is for Del Mar Boulevard, which runs east-west through the center of the view to the right. The second is for California Boulevard; this street is south of the overhead view shown, but the two ramps are visible. Both northbound onramps, and the southbound offramp to Del Mar Boulevard, make use of local streets as frontage roads rather than connecting with the cross streets directly.
CA 134 and Orange Grove Boulevard: Another interchange just west of here is worth looking at. See the overhead view below (which overlaps the western edge of the main overhead view above) for the junction of CA 134 with Orange Grove Boulevard. The interesting topography of this area makes for quite a unique interchange, as well as the many intersecting streets in the area. The basic design is of two half-trumpet interchanges, one for CA 134 to the east and another for CA 134 to the west. Each ends at Orange Grove Boulevard opposite another local cross street. The southern half intersects Colorado Boulevard, another local street, between CA 134 and Orange Grove; there's another directional split at this intersection, which is partly visible in the overhead view. Also note that the eastbound onramp merges onto CA 134 inside the offramp to I-210 and I-710; the same happens in reverse on the westbound side. As a result, traffic between Orange Grove and the I-710 stub or I-210 to the north must use other local streets to access these highways.
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Comments: To fairly judge the design of this interchange, its original intent must be kept in mind. From an email from Jim Barton:
"When this interchange was designed in the 1960's and built in the early '70's, I believe the thinking was that most of the traffic on the 210 eastbound heading into Pasadena from, say the I-5, would, upon reaching the interchange, stay on the mainline and go south on the I-710 toward Long Beach instead of making the elbow to stay on the 210 or west onto the SR-134. Conversely, traffic heading north on the 710 would tend to pick up the westbound 210 simply by staying on the mainline, then use the 210 west to join I-5 to northern California or other points north."
Unfortunately, the result of this thinking is that the two ramps carrying the mainline of I-210, which is a very major northern bypass of Los Angeles, are both exits off of their respective freeways, while the mainline continues as a different highway. This is especially bad for I-210 eastbound traffic, which must exit to the right and then squeeze through a two-lane tunnel under most of the interchange to remain on the correct highway. In my opinion, even if the I-710 extension had been built, it might have been better for this movement to have been more prominent and easier to use. I would recommend a directional split here, with a left exit for the I-210 mainline; that way, the I-210 traffic that wanted to stay on the mainline wouldn't have to exit to the right. Other than that problem, though, I think this interchange is reasonably well-built. I like the typical California interchanges such as this one; no left exits (except for the aforementioned anomaly on I-210), no loop ramps, and a stack-like configuration of the left-turn ramps.
Links
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- I-710 at kurumi.com
- I-710 at cahighways.org
- I-710 at interstate-guide.com - Scroll way down to the bottom for some pictures of this interchange.
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A huge thank-you goes to Jim Barton for helping me by pointing out this interchange and sending me a ton of information about its history and its layout.
Corrections? Suggestions? More information is always welcome.
Suggestions for more interchanges to cover on this site are great too.
Contact the author, Dan (known as DanTheMan on misc.transport.road):
twowheel@email.com
