A lighting system having a plurality of lighting devices continuously arranged along the longitudinal direction of a tunnel, such that the distance between the lighting devices corresponds to the flicker frequency for the speed of traffic traveling through the tunnel. Each of the lighting devices includes a longitudinal base, means for securing the base to the tunnel, a translucent cover, at least one printed circuit board (PCB), and a plurality of light emitting diodes (LEDs) arranged on the PCB to form at least one row. The distance between the LEDs is selected such that the angle of emission of the LEDs, provide in the longitudinal direction, a substantially uniform illumination distribution at the desired height of the lighting device. The means of securing the base to the tunnel enables adjustment of an angle of inclination of each lighting device, relative to the transverse direction of the tunnel to create a substantially uniform light output.