Research on the Recommended Lighting Environment for the Safe Utilization of Marine Space

The Inland Sea (Seto Nai Kai) is a sea area with many cross-sea bridges and a very high level of sea traffic. There is concern regarding the adverse impacts of such illumination sources as road lighting, up-lighting and cable illumination for a number of cross-sea bridges on the operation of fishing boats and large liners. The possible effects of bridge illumination on the safety of sea traffic have been discussed by the Honshu-Shikoku Bridge Authority since the planning stage for bridges linking Honshu Island and Shikoku Island over the Inland Sea and detailed investigations and experiments have been repeatedly conducted. This study was initiated based on the belief that it is of crucial importance to verify the propriety of the standards for bridge illumination set by the Authority for fishermen and ship operators navigating around and under these bridges as some 10 years have now passed since the completion of all of the planned bridges. A questionnaire survey with fishermen and ship operators was conducted under the study to evaluate the effects of bridge illumination. As a result, it was found that bridge illumination poses no problems for the safe navigation of ships, proving the propriety of the road lighting standards set by the Authority.