Ajokaista

Ajokaista is a driving lane on a road, intended for the movement of motor vehicles in a specific direction. It is defined by road markings and traffic signs and forms part of the roadway’s overall lane structure. On multi-lane roads, ajokaistat run parallel in the same direction, while opposing directions are separated by a median or by solid lines. The width of a driving lane varies by road type and locality, typically ranging from about 2.5 to 3.5 meters.

Markings and rules governing ajokaistat are based on lane lines. A dashed line between ajokaistat generally allows changing lanes when it is safe, while a solid line usually prohibits crossing the line except in emergency or to avoid danger. The center line between opposite-direction traffic indicates whether overtaking is permitted in the preceding lane. In practice, drivers must travel within the ajokaista designated for their direction and only change lanes where permitted by markings and traffic conditions.

Special-purpose lanes are not considered standard through ajokaistat. Examples include turning lanes, which may be added to facilitate turning maneuvers, and dedicated bus or bicycle lanes, which have their own restrictions and are used by their designated users at specified times. Drivers must observe signs and markings to avoid using a lane for an improper purpose.

Safety and enforcement: Maintaining lane discipline—staying in the correct ajokaista, signaling lane changes, and avoiding weaving between lanes—contributes to road safety and is subject to traffic enforcement. Violations can carry penalties and increase crash risk.