# Assumed permission - legal question **URL:** \ **Category:** Factual Questions\ **Created:** [June 5, 2011, 3:01pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393 "2011-06-05T15:01:53Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![G-SE](https://avatars.discourse-cdn.com/v4/letter/g/f0a364/32.png) [@G-SE](https://boards.straightdope.com/u/G-SE)\ **Post date:** [June 5, 2011, 3:01pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/1 "2011-06-05T15:01:53Z")
I read about this somewhere but can no longer find any relevant info, so I’m hoping that maybe someone here can help me out. Say you are driving down the road and you come across 3 intersections in a row, all with “no u-turn” signs posted. The next intersection there is no sign, so you can assume that a u-turn is permitted since there is no sign. I used the u-turn as just an example. What I read was talking about a general legal defense (not just traffic offenses) based on this logic - assuming something is allowed because it is officially posted as “not allowed” somewhere else. They actually had used a legal term for it, but I can’t remember what is was. I wanted to ask more questions regarding this, but thought it would help to know the term first if it existed. ---
**Author:** ![WotNot](https://avatars.discourse-cdn.com/v4/letter/w/e19b73/32.png) [@WotNot](https://boards.straightdope.com/u/WotNot)\ **Post date:** [June 5, 2011, 4:17pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/2 "2011-06-05T16:17:16Z")
It sounds like you’re thinking of “the exception proves the rule”. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 5, 2011, 4:26pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/3 "2011-06-05T16:26:55Z")
> [@WotNot](#): > > It sounds like you’re thinking of “the exception proves the rule”. I don’t think so. If there is no NO U-TURN sign at an intersection, it’s legal to make a U-turn. Where I’ve driven, it is legal to make a right turn at a red light (after coming to a stop) if there is no NO TURN ON RED sign. In California there is no law prohibiting motorcycles from operating between lanes of traffic, so it’s legal to do. How do you make a U-turn? Well, first you put her hind legs in a boot…\* \*U = ‘ewe’. 😉 ---
**Author:** ![WotNot](https://avatars.discourse-cdn.com/v4/letter/w/e19b73/32.png) [@WotNot](https://boards.straightdope.com/u/WotNot)\ **Post date:** [June 5, 2011, 4:37pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/4 "2011-06-05T16:37:02Z")
> [@Johnny\_L.A](#): > > I don’t think so. If there is no NO U-TURN sign at an intersection, it’s legal to make a U-turn. That’s right, yes. The NO U-TURN sign is a specific exception to the general rule that U-turns are allowed. The general rule (in this case that U-turns are legal) can be inferred from the existence of the exceptions to it (the signs). ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [June 5, 2011, 4:52pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/5 "2011-06-05T16:52:44Z")
[The Master speaks](http://www.straightdope.com/columns/read/731/whats-the-meaning-of-the-expression-thats-the-exception-that-proves-the-rule) (eventually) on “the exception that proves the rule”. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 5, 2011, 7:43pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/6 "2011-06-05T19:43:18Z")
Whether a U-turn is permitted at an intersection is dependent upon the jurisdiction. In some states it is illegal to make a U-turn within 50 feet of an intersection. If that is the state law, or if it is a local municipality law, it is illegal whether a sign is posted or not. Johnny L.A.: > [@](#): > > In California there is no law prohibiting motorcycles from operating between lanes of traffic, so it’s legal to do. That’s ridiculous. Motorcycles in California, I’m sure, are governed by the Uniform Motor Vehicle Act. I’m sure if you research that Act in California, “motor vehicles” will include motorcycles, and I’m sure motor vehicles are to be driven in one lane only. “Exclusion by omission” applies to laws that specify what is included. If some act or object is not included in the list, then that act or object is excluded from the law. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 5, 2011, 8:08pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/7 "2011-06-05T20:08:22Z")
> [@barbitu8](#): > > Johnny L.A.: That’s ridiculous. Motorcycles in California, I’m sure, are governed by the Uniform Motor Vehicle Act. I’m sure if you research that Act in California, “motor vehicles” will include motorcycles, and I’m sure motor vehicles are to be driven in one lane only. [You would be wrong](http://www.chp.ca.gov/html/answers.html). > [@CHP](#): > > **Can motorcycle riders “split” lanes and ride between other vehicles?** > Lane splitting by motorcycles is permissible but must be done in a safe and prudent manner. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 5, 2011, 9:36pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/8 "2011-06-05T21:36:01Z")
From the California Motorcycle Handbook: > [@](#): > > Cars and motorcycles each need a full lane to operate safely. Lane sharing is not safe. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 5, 2011, 9:47pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/9 "2011-06-05T21:47:16Z")
It says it is not safe. It does not say it’s illegal. By contrast, the California Highway Patrol (official web page linked previously) specifically says that it _is_ legal. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [June 5, 2011, 9:59pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/10 "2011-06-05T21:59:46Z")
> [@barbitu8](#): > > “Exclusion by omission” applies to laws that specify what is included. If some act or object is not included in the list, then that act or object is excluded from the law. That’s what I was thinking. If the first three intersections had three signs saying “no left turns”, “no right turns”, and “no u turns”, and the fourth intersection only had “no left turns” and “no right turns” signs, then you could make a reasonable assumption that u turns were allowed at this intersection. It’s a location where illegal activities were being defined. But you can’t just come up to an intersection with no signs and assume the lack of a sign specifically permits u turns. The lack of a sign in this location might indicate all kinds of turns are allowed or it might just mean that there’s no signs posted here. For example, you might see a sign at the beach that says “No nude sunbathing”. You almost certainly wouldn’t see a “No nude sunbathing” sign in the lobby of the public library but that doesn’t mean it’s allowed there. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [June 5, 2011, 10:24pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/11 "2011-06-05T22:24:12Z")
> [@Johnny\_L.A](#): > > It says it is not safe. It does not say it’s illegal. > > By contrast, the California Highway Patrol (official web page linked previously) specifically says that it _is_ legal. Your link was to the Cal. Hwy Patrol, and its opinion was given. It cited no statute or any law. IMHO, if it’s not safe, it’s not legal. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [June 5, 2011, 10:32pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/12 "2011-06-05T22:32:50Z")
> [@WotNot](#): > > That’s right, yes. The NO U-TURN sign is a specific exception to the general rule that U-turns are allowed. The general rule (in this case that U-turns are legal) can be inferred from the existence of the exceptions to it (the signs). Well, we arrive at that inference by way of standard logic, and it’s generally correct that for most jurisdictions that U-turns are okay at such places unless otherwise posted. In the world of traffic signs, however, sometimes signs are put up simply to emphasize the need for caution. In California, every intersection–with certain exceptions–is an implied crosswalk. According to traffic codes, if you see someone step off a curb with the clear intent to cross the street, you must yield to the pedestrian, even if no signs are posted saying “crosswalk.” Nevertheless, at intersections with heavy pedestrian traffic they sometimes will put up a sign and white lines at intersections to warn motorists that people often cross there. This causes people to falsely believe that at other intersections, with no markings, they have no obligation to yield. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [June 5, 2011, 10:43pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/13 "2011-06-05T22:43:43Z")
> [@barbitu8](#): > > Your link was to the Cal. Hwy Patrol, and its opinion was given. It cited no statute or any law. IMHO, if it’s not safe, it’s not legal. I’m pretty sure the CHP is trying to say that if traffic is moving fairly quickly, don’t try to share lanes or go hot-dogging next to cars. But in a traffic jam–with cars inching along–it actually can help matters to get the motorcycles out of the way by letting them pass “between” lanes, so they won’t violate you. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [June 5, 2011, 10:54pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/14 "2011-06-05T22:54:15Z")
> [@barbitu8](#): > > Your link was to the Cal. Hwy Patrol, and its opinion was given. It cited no statute or any law. IMHO, if it’s not safe, it’s not legal. How can someone cite a law that does not exist? The official site of the CHP claiming that something is not illegal (meaning there is no law forbidding it to be found or cited anywhere) is not an opinion. What makes you think that a statement like that from the CHP’s Official Page would be an opinion? And your opinion that not safe equals not legal isn’t based on any logical process or legal document anywhere. Just admit you are wrong and move on. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 5, 2011, 11:05pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/15 "2011-06-05T23:05:14Z")
> [@barbitu8](#): > > Your link was to the Cal. Hwy Patrol, and its opinion was given. It cited no statute or any law. IMHO, if it’s not safe, it’s not legal. There is no law that says, ‘It is legal to split lanes on a motorcycle.’ Similarly, there is no law saying ‘It is legal to drink coffee while operating a motor vehicle.’ The point is that neither are _illegal_. Your link gives the opinion that lane-splitting is not safe. It does not say anything about whether it is legal. My cite is from an agency tasked with _enforcing driving laws_. This law enforcement agency says that lane splitting ‘is permissible’. ‘Is permissible’ means ‘not illegal’. I racked up well over 100,000 miles on a motorcycle on L.A. freeways. Many miles of those saw me following, or being followed by, CHP officers on motorcycles while riding between lanes of traffic. Many more times I have passed, and been passed by, CHP officers in patrol cars while splitting lanes. One would think that in all of those miles, and in frequent proximity to CHP officers while I was lane-splitting, I’d be pulled over and ticketed. Would you like to know how many times I was pulled over? Zero. _One_ time I got a warning – not for splitting lanes, but for riding between two sets of double-yellow lines separating the carpool lane from the other lanes. The officer used his PA to say, ‘Remember not to ride between yellow lines,’ and nothing more. Furthermore, the only lane-splitters I saw that were pulled over were ones that were not operating their vehicles ‘in a safe and prudent’ manner. > [@](#): > > [http://www.dmv.ca.gov/pubs/vctop/d11/vc21755.htm](http://www.dmv.ca.gov/pubs/vctop/d11/vc21755.htm) > > 1. (a) The driver of a ( )[sup]1[/sup] vehicle may overtake and pass another vehicle upon the right only under conditions permitting ( )[sup]2[/sup] that movement in safety. In no event shall ( )[sup]2[/sup] that movement be made by driving off the paved or maintraveled portion of the roadway. > > (b) This section does not prohibit the use of a bicycle in a bicycle lane or on a shoulder. If you want a [legal opinion](http://www.bestattorney.com/california-motor-vehicle-code/prohibited-areas-for-vehicles-21714.html) (emphasis mine): > [@](#): > > **California Motor Vehicle Code 21714** > > Motorcyclists or Motorized Bicyclists; Operation of Vehicle; Prohibited Areas > > California Vehicle Code 21714 makes it illegal to ride on, or immediately adjacent to, markers designating lanes or between two or more vehicles traveling in adjacent lanes. This is often referred to as lane splitting. > > Vehicle Code 21714 only applies to fully enclosed three-wheeled motorcycles and cars. Of course you’ve already been given the legal opinion of the department that enforces the laws. > [@barbitu8](#): > > ]IMHO, if it’s not safe, it’s not legal. Cigarettes are not safe, and they are legal. Your opinion is not the law. You may not like it, but it is legal to split lanes on a motorcycle in California. . ---
**Author:** ![WotNot](https://avatars.discourse-cdn.com/v4/letter/w/e19b73/32.png) [@WotNot](https://boards.straightdope.com/u/WotNot)\ **Post date:** [June 5, 2011, 11:39pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/16 "2011-06-05T23:39:11Z")
> [@guizot](#): > > Well, we arrive at that inference by way of standard logic, and it’s generally correct that for most jurisdictions that U-turns are okay at such places unless otherwise posted. > > In the world of traffic signs, however, sometimes signs are put up simply to emphasize the need for caution. In California, every intersection–with certain exceptions–is an implied crosswalk. According to traffic codes, if you see someone step off a curb with the clear intent to cross the street, you must yield to the pedestrian, even if no signs are posted saying “crosswalk.” Nevertheless, at intersections with heavy pedestrian traffic they sometimes will put up a sign and white lines at intersections to warn motorists that people often cross there. This causes people to falsely believe that at other intersections, with no markings, they have no obligation to yield. I dare say you’re right, but **G-SE** did say in the OP that the road signs were simply an example, by way of illustration, and that what was wanted was a term for the general legal principle. I can’t help thinking that citations from the California Motor Vehicle Code, enlightening though they surely are, may be something of a red herring in that context. 😉 ---
**Author:** ![G-SE](https://avatars.discourse-cdn.com/v4/letter/g/f0a364/32.png) [@G-SE](https://boards.straightdope.com/u/G-SE)\ **Post date:** [June 6, 2011, 12:52am UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/17 "2011-06-06T00:52:50Z")
> [@WotNot](#): > > I dare say you’re right, but **G-SE** did say in the OP that the road signs were simply an example, by way of illustration, and that what was wanted was a term for the general legal principle. Thanks so far everyone on your input, but yes, the U-turn was just an example. If I remember correctly where I had read about this, it involved local authorities that were apprehensive about putting up signs noting “XXXXX not permitted here” because it would imply that it was permitted elsewhere, when in fact, it was not permitted anywhere. That’s why I was hoping to learn a term for it, so I could possibly find the original article and discuss it further. ---
**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\ **Post date:** [June 6, 2011, 12:17pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/18 "2011-06-06T12:17:40Z")
> [@G-SE](#): > > I read about this somewhere but can no longer find any relevant info, so I’m hoping that maybe someone here can help me out. > > Say you are driving down the road and you come across 3 intersections in a row, all with “no u-turn” signs posted. The next intersection there is no sign, so you can assume that a u-turn is permitted since there is no sign. > > I used the u-turn as just an example. What I read was talking about a general legal defense (not just traffic offenses) based on this logic - assuming something is allowed because it is officially posted as “not allowed” somewhere else. They actually had used a legal term for it, but I can’t remember what is was. > > I wanted to ask more questions regarding this, but thought it would help to know the term first if it existed. I’m not so sure that this would be true in a court of law, though one might be able to argue good faith and get a charge dismissed or reduced to a trivial sentence. Many public schools have “drug free” signs when you enter them, but illegal drugs are not allowed anywhere in the state. You can’t have a few crack rocks and then say, “well, the high school across the street says ‘No Drugs’, so I figured they were OK here.” ---
**Author:** ![Rachellelogram](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rachellelogram/32/8689_2.png) [@Rachellelogram](https://boards.straightdope.com/u/Rachellelogram)\ **Post date:** [June 6, 2011, 2:05pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/19 "2011-06-06T14:05:07Z")
I don’t know that u-turns are a universal example of this principle. Some municipalities ban u-turns completely, while others don’t. If you travel long enough on a road, you’re bound to cross into banned u-turn territory at some point. ---
**Author:** ![Ann\_Hedonia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ann_hedonia/32/319_2.png) [@Ann\_Hedonia](https://boards.straightdope.com/u/Ann_Hedonia)\ **Post date:** [June 6, 2011, 2:30pm UTC](https://boards.straightdope.com/t/assumed-permission-legal-question/584393/20 "2011-06-06T14:30:36Z")
One of my favorite traffic signs is one that advises motorists to “Wait for Green Light Before Proceeding”…This sign shows up at intersections with dedicated left turn cycles ( or multiple cycles for other reasons )and I have assummed that it is there to warn motorists against “jumping the gun” when they see traffic in the other direction stop. However, I would never construe the absence of such a sign to mean that it is OK to proceed without a green light. [Next page](https://boards.straightdope.com/t/assumed-permission-legal-question/584393.md?page=2)