During my last trip to France via car I noticed that French freeways (autoroutes) have a somewhat strange road marking I am not familiar with.

Usually, there are two lanes going my direction on a freeway. These lanes are separated by a dashed line indicating I am allowed to cross this line to pass cars by moving to the left lane.

A few hundred meters before each exit the frequency of these dashes changes. They are much closer together but still don't form a solid line. As soon as the exit is passed, the line changes back to dashes spread further apart, just as before.

In case you do not know what I mean, have a look at e.g. this freeway exit near Paris on Google Maps.

What do these dashes near the exit mean? Am I supposed to not change lanes in this area?

  • You are allowed to change lanes here (AFAIK!). In fact, I believe that the change in the dash style is to remind you to expect people changing lanes a lot; just a reminder to be cautious because you are now approaching a junction. We do this in the UK as well.
    – Calchas
    Commented May 14, 2015 at 20:19
  • 1
    @Calchas hmm, I always assumed that it meant "exit approaching, do not change lanes unless you are in the wrong lane for the exit.
    – phoog
    Commented May 14, 2015 at 20:30
  • I don't think that the change in dashed lines (as described in the question) exists on English motorways and dual-carriage ways. Commented May 15, 2015 at 8:12
  • 3
    In UK they explain dashed lines as: the closer they are the more attention you need to put in the road ( And you can usually see them near exit or when a motorway split in two like this: goo.gl/maps/GvnH8 )
    – SERPRO
    Commented May 15, 2015 at 9:40
  • 1
    Secret messages ;)
    – Mark Mayo
    Commented May 15, 2015 at 11:13

5 Answers 5


It's called a “ligne de dissuasion” (literally “deterrence line”). The idea is to indicate that it's too late to switch from the leftmost lane to the exit. But it's not strictly forbidden to cross the line, especially in the other direction (from the rightmost lane to the leftmost lane), e.g. to overtake or make some space for someone getting on the motorway.

According to the guidelines published by the ministry using a straight line for that purpose is deemed “too limiting” (“trop contraignant”) and reserved for special situations, when the exit is “particularly difficult”. German motorways have slightly different markings to convey the same idea.

In France, the same markings are also used on country roads, when overtaking is not strictly forbidden but should only be done for particularly slow vehicles. In both cases, it means more-or-less the same thing: Crossing the line is not forbidden but you are encouraged not to do it if you can avoid it.

  • 5
    Living in Germany, these markings are not used at every motorway exit. They are sometimes used at high-traffic exits or entries but not as frequently as in France. Also note that these lines actually prohibit crossing them if you are travelling on the side with the solid line.
    – Chris
    Commented May 14, 2015 at 21:33
  • @Chris If you know the German version then that's easy, it's pretty much the same.
    – Relaxed
    Commented May 14, 2015 at 21:35
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    Well, as I said, the German version explicitly forbids crossing the line. Meaning if you do it anyway, you are breaking the law. Also, it is clear on which side of the line you are not allowed to pass. From what I understand, none of these two points apply to the French version.
    – Chris
    Commented May 14, 2015 at 21:39
  • @Chris Hence the “pretty much”…
    – Relaxed
    Commented May 14, 2015 at 21:42
  • 5
    The German markings you posted mean that you are allowed to cross the Sperrlinie from the side with dashed markings to the side with a continuous line, but not the other way round. At least that's how it is in Austria: fuerboeck.at/verkehrsrecht/bodenmarkierungen/laengs/sperrlinie
    – ASA
    Commented May 15, 2015 at 11:11

This page calls such lines lignes de dissuasion, saying that while crossing is allowed, it is discouraged.

And for what I think is a more reliable site, here is a site that offers tests on the French auto code. It has a page on markings. It offers:

Les lignes de dissuasion

Souvent rencontrées sur les routes étroites et sinueuses. Elles autorisent le dépassement des véhicules très lents. Elles sont composées de traits de 3 m et d'intervalle de 1,33 m.

Which google translates as:

Deterrence lines

Often encountered on the narrow, winding roads. They allow the overcoming of very slow vehicles. They are composed of lines of 3 m and an interval of 1.33 m.

  • I would also note that people will often change lanes regardless to overcome a vehicle slowing down for the exit (leap-frogging), even when the line suggests to avoid doing so, so it's best to be wary... Commented May 15, 2015 at 6:16

According to the Vienna Convention on Road Signs and Signals (http://www.unece.org/fileadmin/DAM/trans/conventn/signalse.pdf), Chapter IV, Article 26, paragraph 2 (a), a broken line can be used (i) "to demarcate lanes" or (ii) "to give warning of the approach to a continuous line ... or of the approach to another section of road presenting a particular danger."

2 (b) goes on to say that "the ratio between the length of the gaps between the strokes and the length of the strokes shall be substantially smaller" when the meaning is that of (a)(ii).


They indicate that traffic will be slowing to leave the at the exit and extend to indicate that slower traffic will be entering.

In Europe, it is not legal to overtake on the nearside, so it is a reminder for polite drivers to move out (if possible) to allow slowing traffic to leave and join.

It is not illegal to cross them, but the gendarmes can always find something wrong if they stop you.

  • Note that these lines are only at the exits, not at the entries. Before the entry even begins, the lines go back to normal.
    – Chris
    Commented May 15, 2015 at 11:14

This is actually a way to tell that, if not driving on the rightmost lane already, it is too late to merge right to reach the exit ramp in safe conditions. Drivers should prepare soon enough to get in correct position to exit before it is reached as there are signs soon enough that mention the remaining distance.

Some reckless drivers still do it, which is a rather dangerous move.

Note: this is completely unrelated to the thick dashes that delimitate the beginning and end of exit and entry ramps. If those dashes are seen on the main roadway delimitating the rightmost lane, they mark a reserved lane for trucks & slow vehicles (60 km/h) during an uphill section. The blue disc sign maked with "VEHICULES LENTS" (slow vehicles) should be seen at the beginning.

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