Double Yellow Lines

[webny99]

a single solid white line is not equivalent to a double solid white line.

How so?

According to the MUTCD:

Section 3B.04 White Lane Line Pavement Markings and Warrants
20   Where crossing the lane line markings is discouraged, the lane line markings shall consist of a normal or wide solid white line.
30   Where crossing the lane line markings is prohibited, the lane line markings shall consist of a solid double white line (see Figure 3B-12).

Hmm. Very subtle difference. I always thought crossing either type was prohibited, but maybe that's because I've rarely seen single white lines outside construction zones. Learn something new every day, I guess.

[jakeroot]

Hmm. Very subtle difference. I always thought crossing either type was prohibited, but maybe that's because I've rarely seen single white lines outside construction zones. Learn something new every day, I guess.

You and a lot of other people. The solid white lines in construction zones are typically used because the roadway is curving around a site, and they are trying extra hard to keep traffic in their respective lanes. Changing lanes is still permitted. If an accident occurs, the driver crossing the solid white may be more likely to be found at-fault. Still, not illegal to cross the line.

Best example: in several west coast states, HOV lanes are separated by a solid white line, throughout its entire length. Crossing the line willy-nilly is discouraged, but obviously not outright illegal since you have to be able to leave and depart the lane depending on your route. Sometimes double-solid white lines are used, but only for two-lane express lanes here. And only because there are toll gantries. This in contrast to the style in British Columbia, where the single solid white has dashed sections to allow entry and exit, since the law in Canada is different.

[US 89]

Best example: in several west coast states, HOV lanes are separated by a solid white line, throughout its entire length. Crossing the line willy-nilly is discouraged, but obviously not outright illegal since you have to be able to leave and depart the lane depending on your route.

Came here to post exactly this - when the express lanes were first put in on I-15 in Salt Lake City, they used this exact setup: single solid white line with no dedicated entry/exit zones (and signed as a “carpool lane”). That didn’t last long, though - after a few years, they switched to the more standard double-white line setup with specific entry/exit points, in preparation for conversion to an HOT setup with toll gantries.

[jakeroot]

Best example: in several west coast states, HOV lanes are separated by a solid white line, throughout its entire length. Crossing the line willy-nilly is discouraged, but obviously not outright illegal since you have to be able to leave and depart the lane depending on your route.

Came here to post exactly this - when the express lanes were first put in on I-15 in Salt Lake City, they used this exact setup: single solid white line with no dedicated entry/exit zones (and signed as a "carpool lane" ). That didn't last long, though - after a few years, they switched to the more standard double-white line setup with specific entry/exit points, in preparation for conversion to an HOT setup with toll gantries.

Interestingly, the Valley Freeway (WA-167) near Seattle has HOT lanes along its entire length, yet it uses a single white line. It was converted to HOT lanes in 2008, and double white lines were installed with entry and exit points. Drivers hated it, so they were removed about five years ago. Drivers can more easily avoid the toll gantries now, but police do watch the lane from time to time. And drivers were crossing the double solid white all the time anyways.

[webny99]

Wow, I had no idea that HOV/HOT lanes existed without designated entry/exit points. The ones I'm familiar with in the Toronto area are totally illegal to float back and forth between the regular and the HOV lane except at a designated point for each interchange. The HOV lane functions almost like its own mini-freeway, with signage to boot. Like this. And this.

[jakeroot]

Wow, I had no idea that HOV/HOT lanes existed without designated entry/exit points. The ones I'm familiar with in the Toronto area are totally illegal to float back and forth between the regular and the HOV lane except at a designated point for each interchange. The HOV lane functions almost like its own mini-freeway, with signage to boot. (Will add some examples later.)

Well, there's your problem! You're looking too far north! As I pointed out with my link to the BC example, Canadian HOV and HOT lanes, if they don't just use dotted lines throughout the entire length, are going to use entry and exit points because you cannot cross a solid white in Canada. That's not the case in the US. Thankfully, in my opinion, since there is a subtedly between "shouldn't change lanes" and "shall not change lanes" that Americans get to appreciate; much the same as the subtedly of the single solid yellow that Canadians get to appreciate.

There are parts of America with similar mini-freeway designs. On the 405 east of Seattle, the express lanes have their own entrances and exits, with their own signage (white instead of green). These do have entry and exit points, and quadruple white lines are used to separate the lanes from the general purpose lanes.

On the 91, in Southern California, there are toll lanes in the center (same as above), with designated entry and exit points with their own signage. Again, quadruple white lines are used, although flexi-posts are also used to further discourage lane changing. I don't know which state lifted the quadruple white style from who, but the 91 used to have quadruple yellow markings (as in common on many other Southern California freeways).

[Revive 755]

How about we add triple yellow lines to the single versus double debate?  I am not sure some of them in Missouri are just from repainting without lining up with the old lines.  Example on US 63

I thought there was also an example on Us 160 in Missouri, but I cannot find it in Streetview.

Though after looking at a similar setup on MO 5, it could be they tried to do two double yellow lines and didn't get the separate quite correct.

[jakeroot]

Those actually look nice, especially that MO 5 example. Something very Nordic about it. I'm not sure exactly what it is.

I mentioned several pages back that, instead of using four yellow lines, WSDOT instead opts to use a single, really thick yellow line to indicate where crossing is 100% prohibited. To follow up the past debate, this may be the only example of a legislated single yellow line in the US. Basically, RCW 46.61.150 indicates that a median island can be formed by yellow pavement markings. Thus, a single yellow 18-inch wide yellow median island:

[jeffandnicole]

a single solid white line is not equivalent to a double solid white line.

How so?

According to the MUTCD:

Section 3B.04 White Lane Line Pavement Markings and Warrants
20   Where crossing the lane line markings is discouraged, the lane line markings shall consist of a normal or wide solid white line.
30   Where crossing the lane line markings is prohibited, the lane line markings shall consist of a solid double white line (see Figure 3B-12).

Hmm. Very subtle difference. I always thought crossing either type was prohibited, but maybe that's because I've rarely seen single white lines outside construction zones. Learn something new every day, I guess.

Never seen a shoulder line?

[jakeroot]

I always thought crossing either type was prohibited, but maybe that's because I've rarely seen single white lines outside construction zones. Learn something new every day, I guess.

Never seen a shoulder line?

I'm gonna guess he means as a divider between lanes. And more to his credit, in most states, everything to the right of the shoulder line is "off the roadway", thus you're not really allowed to cross that line. There are exceptions to the rule for turning, and in some places, passing, but generally it's the division between roadway (driveable area) and non-roadway (non-driveable area). Ergo, don't cross the solid white line.

Still, even in those situations, crossing the shoulder line is not outright banned. But it's something to keep in mind.

[webny99]

LOL, yes, of course I meant between lanes. Shoulder lines are a different story, although when it comes to those, I would apply a logic similar to Canada's logic for single yellow center lines. Cross, (and pass, where the shoulder has been widened to allow it) but do so with caution.

[jeffandnicole]

I always thought crossing either type was prohibited, but maybe that's because I've rarely seen single white lines outside construction zones. Learn something new every day, I guess.

Never seen a shoulder line?

I'm gonna guess he means as a divider between lanes. And more to his credit, in most states, everything to the right of the shoulder line is "off the roadway", thus you're not really allowed to cross that line. There are exceptions to the rule for turning, and in some places, passing, but generally it's the division between roadway (driveable area) and non-roadway (non-driveable area). Ergo, don't cross the solid white line.

Still, even in those situations, crossing the shoulder line is not outright banned. But it's something to keep in mind.

Bingo.

Everything you said is true about a single line, subject to individual state statute. It doesn't matter where the line is located.  And that was my point: A single line isn't meant to be crossed, but its prohibition isn't absolute.

LOL, yes, of course I meant between lanes. Shoulder lines are a different story, although when it comes to those, I would apply a logic similar to Canada's logic for single yellow center lines. Cross, (and pass, where the shoulder has been widened to allow it) but do so with caution.

For the reasons I mentioned above, they're actually the same story. Motorists often think of the placement of the line to mean different things, but ultimately the meaning is actually the same.

Referencing the MUTCD, it states that the single white line can be used in various situations, but its intent is the same. While the MUTCD is guidance, the absolute law comes down to individual states and their interpretation how to treat the single line.
https://mutcd.fhwa.dot.gov/knowledge/faqs/faq_part3.htm#lmq1

[webny99]

LOL, yes, of course I meant between lanes. Shoulder lines are a different story, although when it comes to those, I would apply a logic similar to Canada's logic for single yellow center lines. Cross, (and pass, where the shoulder has been widened to allow it) but do so with caution.

For the reasons I mentioned above, they're actually the same story. Motorists often think of the placement of the line to mean different things, but ultimately the meaning is actually the same.

OK, fair enough. That's mostly due to my lack of knowledge about white lines between lanes, and the fact that I'm only familiar with them in construction zones. Those tend to have so many special rules, laws and regulations that I tend to just assume something is illegal in a construction zone if there's even a chance of it being so.

[jakeroot]

Referencing the MUTCD, it states that the single white line can be used in various situations, but its intent is the same. While the MUTCD is guidance, the absolute law comes down to individual states and their interpretation how to treat the single line.
https://mutcd.fhwa.dot.gov/knowledge/faqs/faq_part3.htm#lmq1

I had not seen that section before. Thanks for sharing.

[kphoger]

Those actually look nice, especially that MO 5 example. Something very Nordic about it. I'm not sure exactly what it is.

To my eyes, it looks a lot like Sweden's 2+1 highways.

[jakeroot]

Those actually look nice, especially that MO 5 example. Something very Nordic about it. I'm not sure exactly what it is.

To my eyes, it looks a lot like Sweden's 2+1 highways.

Yes yes, that's exactly what I had in mind. Thank you for the link. I think MoDOT was inspired by those highways when they rebuilt some of their single-carriageway rural routes however many years ago.

[stevashe]

* Both Washington and Oregon use a wider double yellow spacing. Example from WA; example from OR.

I've gotten the impression that wider spacings like this are a remnant of older striping patterns from back before the MUTCD formalized and standardized the yellow centerline striping patterns.

Some states used white broken lines as the center marking, but would have solid yellow lines on either side to indicate no passing (I've seen reference to this on old Nevada DOH maps). So you could have three closely-spaced lines down the center. Double yellow becomes the new norm? Cool, just eliminate the broken white in the middle.

I hadn't considered that, but it makes perfect sense.

From the very limited research I've done on the matter, it seems that some states quickly rebuilt their standards when yellow center lines came into force, but others drug their feet. WA seems to have been one of the last states to transition, since A) there are still some roads with white center lines, B) I've seen more than a few photos from recent years showing white center lines, well after when I thought the rule went into place, and C) (possibly) their double yellow line spacing still has a spot for a white line down the middle. I think that's completely logical.

Where have you seen white centerlines in WA? Are you sure they weren't just faded yellow lines? Those can sometimes look white, especially in bright sunlight.

Also I'm not so sure on that being the reason for having wider spacing, though it does indeed leave enough space for a line in between since the gap is 12", so a 4" line with 4" of space on both sides fits nicely in between the two solid yellows. You can actually see that here on WA-202 where a passing zone has been converted to no passing. I suspect this may have more to do with the reason for the wider spacing since it allows making this change without having to remove the dashed line or pain the double yellow off-center. I also think wanting to encourage more separation between opposing traffic is a factor since only WSDOT uses the 12" spacing and state highways generally have higher speeds where this is more of a concern (especially considering that cities are generally responsible for striping on state highways within  city limits).

It's also worth noting that solid/broken lines that prohibit passing in one direction do have a more normal space of 4", the same width as the stripes, as shown here on US-2. This makes it so that there are effectively three "zones" where the stripes are painted, one for the dashed line in the middle and one for each solid line to the side, and each type of line is always painted in the same "zone", which I like and think looks good since a dashed line will always be in the exact center of the roadway. In contrast, with only 4" spacing between double yellows, the dashed line must be painted in the same "zone" as the solid line where passing is allowed in one direction, meaning it changes positions slightly when transitioning from solid and broken lines to a single broken line.

[jakeroot]

Where have you seen white centerlines in WA? Are you sure they weren't just faded yellow lines? Those can sometimes look white, especially in bright sunlight.

Definitely not faded. They are white. I can't link examples as I'm on currently on a plane but you can Google them:

* Tacoma: N Yakima, west of 3rd St, for a substantial number of blocks (10+ easily); single solid white line. There are some stretches where some yellow had been previously painted as a dashed line directly over the solid white, but have largely faded. The white is still very visible.

* Tacoma: East 25th, west of Portland Ave for about ten blocks. Bits of it have been worn away due to the poor quality of the street (loaded with potholes).

EDIT: Pictures (in order listed above)...both were taken within the last couple months, and reflect current conditions: