The nomenclature and meaning of the longitudinal white markings are as follows: a) Continuous longitudinal marking. A longitudinal marking consisting of a continuous line on the roadway means that no driver with his vehicle or animal may cross it or drive his vehicle on it or, when the marking separates the two directions of traffic, drive on the left side of it. A longitudinal marking consisting of two continuous lines attached to each other has the same meaning. A continuous white line on the roadway may also indicate the existence of a special lane, and drivers of vehicles travelling in the special lane may cross it with due care and leave it when the manoeuvre or the destination they intend to follow so requires. In this case the marking is noticeably wider than in the general case. b) Broken longitudinal marking. A broken line on the roadway is intended to delimit lanes in order to guide traffic, and means that no driver should drive his vehicle or animal on it, except when necessary and traffic safety permits, on roads with narrow lanes (less than three metres wide). It may also be intended for: 1. To inform the driver approaching a continuous longitudinal marking of the prohibition implied by this marking or of the proximity of a section of road that presents a special risk; in these cases, the separation between the lines is noticeably shorter than in the general case. 2. To indicate the existence of a special lane (to determine the type of vehicle, entry or exit, or other); in this case the marking is noticeably wider than in the general case. c) Double broken longitudinal markings. As a special case of broken lines, double lines that delimit a lane on both sides mean that it is reversible, meaning that traffic on it can be regulated in one direction or another by lane traffic lights or other means. (d) Continuous longitudinal markings attached to broken lines. When a marking consists of a continuous longitudinal line attached to a broken line, drivers must only take into account the line on the side on which they are travelling. When these markings separate different directions of traffic, this provision does not prevent drivers who have overtaken from returning to their normal position on the roadway. e) Intersection guide markings. These indicate to drivers how a particular manoeuvre should be performed at an intersection. f) Edge and parking lines. For the purposes of this article, longitudinal lines that delimit, to make them more visible, the edges of the roadway or parking spaces referred to in article 170 are not considered to be included.