I never understood why certain interchanges aren't full ones. For example, how come at the I-5/CA-134 interchange there is no SB 5 to WB 134 ramp or at the Hollywood Split there is no NB 101 to WB 134 or SB 170 to NB/WB 101? I know the freeways intersect at an angle but I would still think they would be full interchanges. The 605/5 interchange has a SB 605 to NB 5 and NB 5 to SB 605 connector and the 5 meets with the 605 at an angle. The only acute freeway interchange that makes sense without full interchange is the 91/5 interchange.
The WB 134-SB 101/NB 101-EB 134 ramps were never built because that's where the proposed Laurel Canyon Freeway was supposed to have met up with both the Hollywood and Ventura Freeways. And I think there was some community opposition about the EB 134-NB 5/SB 5-WB 134 ramps (the LA Times ran an article a few years back on that interchange).
Also, if 5/605 is a full interchange, why isn't the 5/710 a full interchange?
My presumption was most incomplete interchanges were due to space constraints and/or limitations, but it could also be the result of community opposition, as mentioned.
That said, I believe there are long-term plans to completely rebuilt the 101/134/170 interchange, connected to another proposal of double-decking the 101 through the Valley.
Some of the incomplete interchanges are also due to the presence of other options in the area. To use SB I-5 to WB CA-134 as an example: If you are coming from, say, San Fernando or Arleta on I-5 south and are heading to, say, Thousand Oaks or North Hollywood, you would have taken CA-170 to US-101 (or the Magnolia exit) instead. If you're past CA-170, at that point it makes more sense (and not much more time for most people) to take surface streets to CA-170 or CA-134 rather than I-5. Plus, by staying on I-5 you'd be backtracking a few miles to the east, which would probably negate any time savings over surface streets.
In other words, the redundancy that the ramp would represent for most people combined with the costs make it unnecessary.
Same probably holds true for US-101 north to CA-134 east; however, I agree that CA-170 south to US-101 north (west) would make sense.
Quote from: JustDrive on August 08, 2012, 12:43:15 AM
Also, if 5/605 is a full interchange, why isn't the 5/710 a full interchange?
Originally, Route 90 was to provide some of the movements that aren't presently at 5/710 (the 60/710 stack provides several others, basically SB 710 to NB 5). With 90 long canceled except on paper, ramps from NB 710 to SB 5/NB 5 to SB 710 are slated to be added in the next few years:
https://www.aaroads.com/forum/index.php?topic=6814.0