Author Topic: CA: US 101/East LA Interchange  (Read 206 times)

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Offline Bickendan

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CA: US 101/East LA Interchange
« on: July 26, 2022, 04:02:38 pm »
Nitpick: US 101's terminal point shouldn't be CA 60 but I-5 southeast of Euclid Avenue, as there's a US 101 only half-interchange with Euclid, labeled as 1 on OSM (GMSV shows no exit number on the final overhead, nor any gore exit assembly). This might require an adjustment on I-5's .wpt? I'm not sure this plays well with the one-point-per-interchange rule in this instance.

It's a loosely similar situation with I-405 and its exit 1A at Harbor Drive in the Ross Island Maze under the Marquam Bridge ramps.

Offline oscar

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Re: CA: US 101/East LA Interchange
« Reply #1 on: July 30, 2022, 12:54:36 am »
Nitpick: US 101's terminal point shouldn't be CA 60 but I-5 southeast of Euclid Avenue, as there's a US 101 only half-interchange with Euclid, labeled as 1 on OSM (GMSV shows no exit number on the final overhead, nor any gore exit assembly). This might require an adjustment on I-5's .wpt? I'm not sure this plays well with the one-point-per-interchange rule in this instance.

That would be in line with one of neroute2's suggestions (made long ago, when I was deferring most changes to non-usaca routes not needed to get usaca finalized) that US 101 be extended southeast to the merge with I-5 near Lorena St. But he also pointed out that US 101's mile 0 seemed to be north of the CA 60 interchange, approximately where 101 passes under westbound I-10 (with no connection with 101), and 101's interchange with 7th St. That would mean truncating, rather than extending, US 101. It is also more consistent with Caltrans' online exit list for US 101, which has the 7th St. interchange as 101's southernmost exit, as well as the online Postmile Query Tool, which treats the 101 roadway south of 7th St. as part of route 5 rather than route 101. Also, the 7th St. interchange happens to be US 101's legislative south end, though that language doesn't necessarily preclude Caltrans from fudging the endpoint a little.

This is a messy and confusing situation. Given conflicting information, I would split the difference between the "extend" and "truncate" options and just leave the US 101 route file mostly as is, with 101 ending at CA 60. ("Mostly" in order (a) tweak 101's I-5/10 point, or at least its label, given the lack of an actual direct connection to I-10, and also (b) relabel adjacent US 101 waypoints, some of which are in use.)
« Last Edit: July 30, 2022, 05:46:15 pm by oscar »

Offline Bickendan

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Re: CA: US 101/East LA Interchange
« Reply #2 on: July 30, 2022, 01:39:19 am »
That is messy, considering I-5 does not interact with Euclid Ave while the Santa Ana Freeway does... a brief moment of the Santa Ana not being part of I-5 nor US 101 x.x
(Extending 101 down would actually break my full California clinch of 101, but it'd give me another piece to seek out next time I'm in SoCal!)

Offline oscar

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Re: CA: US 101/East LA Interchange
« Reply #3 on: August 25, 2022, 07:47:49 pm »
I'm now inclined to truncate US 101 at what is now I-5/10, which also is very close to SB exit 1A (to 7th St.), the southernmost exit in Caltrans' US 101 exit list. As I noted above, Caltrans considers the roadway continuing south of exit 1A, the exit to CA 60 (I-5 exit 134A), Euclid Ave. (I-5 exit 133), and beyond as part of I-5, even though it's in the median for I-5's other lanes.

I would relabel I-5/10 to 1A/5, or 1A/I-5. That part of the interchange connects both an exit 1A ramp from SB US 101 to 7th St, and also US 101's SB through lanes to I-5 (but not I-10). The relabel would also let us use 1A (point in use, for what really is exit 1B) as an alt label for exit 1B. Existing waypoint 1B (not in use) would be corrected to 1C (also not in use).

I'll pull this in later, along with at least one non-CA change in my queue.

Offline yakra

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Re: CA: US 101/East LA Interchange
« Reply #4 on: August 25, 2022, 08:42:10 pm »
Shouldn't combine an exit number and a route like that with a slash though. Just route numbers.
The only places where route numbers and exit numbers are combined are with parentheses, when using exit numbers from another route.
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Offline oscar

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Re: CA: US 101/East LA Interchange
« Reply #5 on: August 25, 2022, 09:27:39 pm »
OK, that means:

I-5/10 => 1A +1-5/10 +I-5 +CA60
1A => 1B (no alt label)
1B => 1C

Most of this will go into the Updates table, as well as a mention that existing 101(CA60) => I-5(134A) (anyone who traveled from 101 to 60 or vice versa will have traveled I-5 between its exits 134A and 134B, since that segment will no longer be counted as part of 101).

101's exits 1D, 1E, etc. remain as is.

Offline oscar

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Re: CA: US 101/East LA Interchange
« Reply #6 on: August 31, 2022, 02:40:26 am »
Above changes now in the HB.