ljusssignalerna

Ljusssignalerna, often referred to as traffic lights, are signaling devices positioned at road intersections, pedestrian crossings, and other locations to control competing flows of traffic. Their primary purpose is to improve safety and efficiency by assigning right-of-way to different streams of traffic in a cyclical manner.

The most common type of ljusssignal consists of three lights: red, yellow (or amber), and green. The red light indicates that vehicles must stop before the intersection or designated stop line. The green light signifies that vehicles may proceed through the intersection, provided it is safe to do so and the path ahead is clear. The yellow light serves as a warning that the signal is about to change to red, typically indicating that drivers should prepare to stop or, if already in the intersection or too close to stop safely, proceed with caution.

Variations of ljusssignalerna exist, including those with flashing lights, pedestrian signals (often depicting a walking person or a hand), and bicycle signals. In some regions, countdown timers are incorporated into pedestrian signals to indicate the remaining time for crossing. The operation of ljusssignalerna can be fixed-time, meaning they cycle through their phases at predetermined intervals, or actuated, meaning they respond to the presence of vehicles or pedestrians detected by sensors. The implementation of ljusssignalerna has significantly contributed to reducing traffic accidents and improving traffic flow in urban and suburban environments worldwide.