HOW TO PREVENT BRIDGE ACCIDENTS BY SENDING HEIGHT MEASUREMENT TO SHIPS

Abstract

Collisions with bridges are still a problem in inland navigation and often result in restricted or blocked transportation of people and goods. In addition to the impact on the statics of the bridge, the passing roads, railroads, and power & communication lines, logistics companies and their suppliers are deprived of an important lifeline. Insufficient height clearance also poses a high risk of serious injury to the crew due to damage to the vessels bridge. The vast majority of accidents (e.g. insufficient lowering of the lookout, incorrect readings of staff gauges or excessive container loads) are caused by human error. Tidal rivers and water level effects from nearby locks also affect the under-bridge clearance over time. As part of the EU project 'RIS-COMEX II', a feasibility study is being carried out to determine the vessels height in relation to the water level using LiDAR (Light Detection and Ranging) sensors. The installed sensor system detects vessels approaching a bridge and measures their highest point (including all superstructures) in relation to the current water level. The measurements are transmitted via AIS as an Application Specific Message (ASM) containing the vessel's MMSI, Name, position and its height for display in the Inland ECDIS on board. The aim of the study is to evaluate the accuracy and precision of the system over a period of one year. This study is also done to gain experience on the extent to which environmental conditions affect the height measurements and also physically degrade the installed setup. In addition, the study investigates transmission frequencies, latencies of tidal measurements, and time from measurement to on-board display. The study will be conducted in an area that has recently experienced two consecutive serious bridge collisions, disrupting logistics to major German ports. The vessel height measurement is performed with LiDAR sensors covering the entire river width of about 50 m and capable of measuring traffic from both directions. The paper reports on the initial study results based on first traffic measurements.