We present the results of a comparison of light pollution produced by some light installations for roadway lighting as obtained with the software Roadpollution. Luminaires with an direct upward flux factor apparently as small as 0.2% and 2.2% produce increases of light pollution even of the order of 20% and 200% respectively. Reflection of downward light wasted outside of the road adds approximately another 50% – 100%, depending on the reflectivity of the surrounding surfaces and the fraction of wasted light flux, and should be minimized as much as possible.
