Carpool Lane: What Do Those Yellow & White Lines Mean?

Recently, we were looking to insure a new client’s car so we ran their driving record.  It came up with an improper lane violation regarding the carpool lane.  I had spoken to the person who referred the client to our office and they were a bit confused.  They thought one was able to exit the carpool lane at any time, due to the fact that there was a white line to the left of the solid yellows.  I disagreed, but was always curious as to why that white line was there.  I’ve never seen anyone exit the carpool lane and get a ticket, so I couldn’t say for sure. To find out what those lines really mean, I looked at the DMV website and found the following information:

The California Driver Handbook (2013)
•Pg. 31 – Two solid yellow lines mean “no passing”.  You’re not supposed to drive on the left-hand side of these lines unless you’re “in a carpool lane that has a designated entrance on the left”.

Rules of the Road and Safe Driving Practices
•Pg. – 23, Section 07.B.06 – Carpool Lanes
Freeway carpool lanes – “may require that once in a carpool lane you cannot cross over double lines to exit the carpool lane but must wait until you have a broken line”

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This only partially answered my question.  It states that crossing the solid yellows are not allowed, but it still did not tell me why the white line was there.  It took some more research but I found that according to the California Manual on Uniform Traffic Control Devices (MUTCD) Section 3B.04, a solid white line means that crossing it is discouraged, but not illegal.  Some examples of this would be seen on one-way streets or just before an intersection.  If the conditions are right and you can change lanes safely, go ahead.  However, the carpool lane is an exception.  The white line in this case, is there as a lane barrier and should not be crossed until there is a designated entry/exit place marked by broken lines.

For more information on carpool lanes, check out the FAQs at

6 Responses to “Carpool Lane: What Do Those Yellow & White Lines Mean?”

  1. After reading these questions and answers I think I’ve figured it out, although it is not really clear. I think that perhaps the white line on the inside of the carpool lane means that is it okay to drive to left of those double yellow lines. It is confusing and I’ve often wondered if I could exit because of the white line. I haven’t because didn’t want to chance a ticket. It appears in any other circumstance other than a carpool lane that it would never be allowed to drive to the left of these lines, and I’ve never seen a white line next to them with the exception of the carpool lane.

  2. I believe I have the answer to the origin of the mysterious solid white line inside the double-yellow of the carpool lane.

    Think about when you’re driving on a regular street. The double-yellow represents the dividing line between you and oncoming traffic. If you cross a double-yellow on a regular street you will be driving in the wrong direction.

    Now let’s say you lawfully merge into the carpool lane on a freeway, by crossing over the dashed white line. The dashed line soon ends and is replaced by the double-yellow (with the single white line). The whole reason for the existence of the white line is to let you know it’s ok to be on the left of the double-yellow, i.e. it tells you you are not driving into oncoming traffic on the freeway. Pretty hoky I know, especially since most of the time there’s a concrete median that keeps you on the right side of the road. But if you think about it, it does make sense from a jurisprudence point of view.

  3. Shannon

    I heard (Calif) that if there is a solid white line to the left of a SINGLE SET of double yellow lines – you can exit the carpool lane at any time as long as it’s safe. It’s a bit confusing because there are also instances of there being a DOUBLE SET of double yellow lines. I wish I could post a pic or diagram because it’s hard to describe. I also heard that in the case of a DOUBLE SET of double yellow line – you cannot cross those as opposed to the SINGLE set of double yellows. *sigh* sorry to sound confusing, but I’ve been researching this for a long time and have yet to find it in writing. Even asking police people will get you differing answers :/ argh.

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