AARoads Forum

I apologize if this has been discussed before but I couldn't find anything in the search.

I've been back in SD and LA for work the past few weeks and have a few questions. First, before almost every freeway exit, there is a diagonal line connecting the outside of the shoulder to the right edge of the right lane. What's up with that? I've been coming here for years and never noticed it.

Also, other than the doghouse signals that seem common in LA, I can't think of any other protected/permissive left turns in the state. Is there a reason they don't use them more?

Quote from: realjd on November 09, 2012, 10:25:16 AM
I've been back in SD and LA for work the past few weeks and have a few questions. First, before almost every freeway exit, there is a diagonal line connecting the outside of the shoulder to the right edge of the right lane. What's up with that? I've been coming here for years and never noticed it.

I've never noticed such a thing!  can you point one out on Google aerial view or whatnot?

QuoteAlso, other than the doghouse signals that seem common in LA, I can't think of any other protected/permissive left turns in the state. Is there a reason they don't use them more?

I think the rationale is: too much traffic to justify a safe permissive left.  I don't agree with this, but I do find it plausible.

Quote from: realjd on November 09, 2012, 10:25:16 AM
I've been back in SD and LA for work the past few weeks and have a few questions. First, before almost every freeway exit, there is a diagonal line connecting the outside of the shoulder to the right edge of the right lane. What's up with that? I've been coming here for years and never noticed it.

Perhaps it warns people on the shoulder for whatever reason (including breakdowns, and cyclists where allowed) that they need to either merge back in or be extra careful?

Quote from: agentsteel53 on November 09, 2012, 10:36:33 AM

Quote from: realjd on November 09, 2012, 10:25:16 AM
I've been back in SD and LA for work the past few weeks and have a few questions. First, before almost every freeway exit, there is a diagonal line connecting the outside of the shoulder to the right edge of the right lane. What's up with that? I've been coming here for years and never noticed it.

I've never noticed such a thing!  can you point one out on Google aerial view or whatnot?

QuoteAlso, other than the doghouse signals that seem common in LA, I can't think of any other protected/permissive left turns in the state. Is there a reason they don't use them more?

I think the rationale is: too much traffic to justify a safe permissive left.  I don't agree with this, but I do find it plausible.

I'm posting from my iPad in flight so I can't get a proper google maps link (my aisle seatmate is eating his airline-grade omelette so I can't get my laptop out from the overhead bin - yay first class upgrades!), but if you go to the corner of Missouri and Vine in Oceanside, there is one on SB I-5 right next to that particular corner, leading to the interchange with Oceanside Blvd.

I don't buy the traffic argument for the left turns. Much of California is very rural, and if traffic heavy LA can use doghouse signals, there's no reason the rest of the state can't.

Quote from: NE2 on November 09, 2012, 10:52:52 AM

Quote from: realjd on November 09, 2012, 10:25:16 AM
I've been back in SD and LA for work the past few weeks and have a few questions. First, before almost every freeway exit, there is a diagonal line connecting the outside of the shoulder to the right edge of the right lane. What's up with that? I've been coming here for years and never noticed it.

Perhaps it warns people on the shoulder for whatever reason (including breakdowns, and cyclists where allowed) that they need to either merge back in or be extra careful?

My first thought was that it was to guide people accidentally driving down the shoulder in cases of low visibility back to the travel lanes so nobody accidentally sideswipes them while trying to exit.

Quote from: realjd on November 09, 2012, 12:15:19 PM

I don't buy the traffic argument for the left turns. Much of California is very rural, and if traffic heavy LA can use doghouse signals, there's no reason the rest of the state can't.

LA drivers are used to permissive-only unprotected lefts.

I dunno, I'm pulling items out of an area usually dedicated to digestive finality. 

After some googling, I found a photo of a "California Shoulder Break"

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fb%2Fb7%2FCalifornia_shoulder_break.jpg&hash=8db244e9933ea5424e7da78d55be749b5e3e0f0f)

Quote from: realjd on November 09, 2012, 12:40:12 PM
After some googling, I found a photo of a "California Shoulder Break"

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fb%2Fb7%2FCalifornia_shoulder_break.jpg&hash=8db244e9933ea5424e7da78d55be749b5e3e0f0f)

Nice dangling modifier.  Should read "No thru trucks exceeding 3 tons on Farm Hill Blvd"

Native California-roadgeek here.

The type of shoulder striping realjd is referring to, where the right shoulder line ends and a new one forms to the right and arcs out to form a new right shoulder line, is to indicate an upcoming freeway exit when there is poor visibility like dense fog.  According to the California MUTCD, this angled line is supposed to begin 350 feet prior to the exit.  I know this is standard in California but I am not sure if this is a national standard (my guess is probably not).

Here is an illustration of the standard California freeway shoulder striping I clipped from the California MUTCD...

This is definitely a Californiaism.

Quote from: myosh_tino on November 09, 2012, 01:01:08 PMThe type of shoulder striping realjd is referring to, where the right shoulder line ends and a new one forms to the right and arcs out to form a new right shoulder line, is to indicate an upcoming freeway exit when there is poor visibility like dense fog.  According to the California MUTCD, this angled line is supposed to begin 350 feet prior to the exit.  I know this is standard in California but I am not sure if this is a national standard (my guess is probably not).

As Scott says, it is a Californiaism--I have certainly never seen it used anywhere else.  In California I also think it is not used at lane drops.

Re: Doghouses

I've only seen two up this way. One in Daly City and another in Millbrae (though it's the 101 off-ramp).


Thank you for the information on the shoulder break. When I passed the one up at 101 & Candlestick Park (Tunnel Ave), I always wondered why it was there.