The present report presents four studies that were conducted with the aim to evaluate how electronic billboards (ERS) affect traffic safety. Study 1 is a literature review to examine how billboards impact road safety. The conclusions from the review showed that animated pictures and the location of the billboards have a major impact on driver behaviour as well as that darkness and adverse weather conditions can create glare which makes driving difficult especially for older drivers.The second and third studies compared the speed and the number of accidents before and after the installation of the billboards. Neither difference in traffic volume nor in average speed could be demonstrated. There was nothing in the studied accidents to suggest that the accident was affected by a billboard.The fourth sub-study is a field study investigating 41 drivers (driving and visual behaviour) on the E4 as they pass the billboards. Results showed several cases of visual distraction. The results also show a negative attitude to the billboards for a majority of the drivers.In summary, no effects from the billboards on traffic safety could be showed at the macro level. However, the effects of visual distraction must be taken into consideration and investigated further before deciding whether billboards will be implemented on Swedish roads.