Abstract: Brightness perception under different light sources is an important visual response, because it is related to perceptions of safety. A growing number of studies have been conducted to assess perceptions of scene brightness under light sources differing in spectral content, including results consistent with a role of melanopsin-containing, intrinsically photosensitive retinal ganglion cells in scene brightness. Data from recent studies of scene brightness perception at light levels experienced under nighttime driving conditions are used to compare different models of brightness perception. The data support a role of increased short-wavelength sensitivity for scene brightness perception and a provisional spectral sensitivity model that takes into account the possible influence of melanopsin-containing, intrinsically photoreceptive retinal ganglion cells is suggested as a basis for further investigation. The implications of such a model on brightness perception under several light sources used in transportation lighting are described.