Article 13. Speed and Distance Between Vehicles

1. Every driver of a vehicle shall in all circumstances have his vehicle under control so as to be able to exercise due and proper care and to be at all times in a position to perform all manoeuvres required of him. He shall, when adjusting the speed of his vehicle, pay constant regard to the circumstances, in particular the lie of the land, the state of the road, the condition and load of his vehicle, the weather conditions and the density of traffic, so as to be able to stop his vehicle within his range of forward vision and short of any foreseeable obstruction. He shall slow down and if necessary stop whenever circumstances so require, and particularly when visibility is not good.

2. Domestic legislation shall establish maximum speed limits for all roads. Domestic legislation shall also determine special speed limits applicable to certain categories of vehicles presenting a special danger, in particular by reason of their mass or their load. They may establish similar provisions for certain categories of drivers, in particular for new drivers.

3. The provisions set out in the first sentence of paragraph 2 may not apply to drivers of priority vehicles referred to in Article 34, paragraph 2, or vehicles treated as such in domestic legislation.

4. No driver shall impede the normal progress of other vehicles by travelling abnormally slowly without proper cause.

5. The driver of a vehicle moving behind another vehicle shall keep at a sufficient distance from that other vehicle to avoid collision if the vehicle in front should suddenly slow down or stop.

6. Outside built-up areas, in order to facilitate overtaking, drivers of vehicles or combinations of vehicles of more than 3,500 kg permissible maximum mass, or of more than 10 m overall length, shall, except when they are overtaking or preparing to overtake, keep at such distance from power-driven vehicles ahead of them that other vehicles overtaking them can without danger move into the space in front of the overtaken vehicle. However, this provision shall not apply in very dense traffic or in circumstances where overtaking is prohibited. In addition:
     (a) The competent authorities may exempt certain conveys of vehicles from this provision, or may similarly make it inapplicable on roads where two lanes are allotted to traffic in the direction concerned;
     (b) Contracting Parties and subdivisions thereof may prescribe different figures from those given in this paragraph with respect to the vehicle characteristics concerned.