Effects of traffic characteristics and mounting location on the visibility of on-premise commercial signs

In recent years, there has been a movement in local government regulations toward restricting the mounting height of on-premise, commercial signing and other roadside oriented signs. This has caused some concern among sign designers and fabricators that automobile drivers will have difficulty in seeing and reading many of these low profile signs. These potential visibility difficulties are caused by the presence of other vehicles; either those in front of the subject vehicle, those in the adjacent travel lane, or those traveling in the opposite direction; blocking the line of sight between the subject vehicle driver and any low-mounted, roadside sign. The objective of this research was to determine the probability of another automobile blocking the line of sight between the driver of a subject vehicle and an on-premise, low-mounted, roadside sign. The results indicated that this probability is a function of the position of the subject vehicle, the position(s) of one or more object vehicles, the volume of vehicles on the road, and the speed of the vehicles on the road.