Backwards compatible extension of CAMs/DENMs for improved bike safety on the road

In the past, research and standardization in the field of Intelligent Transportation Systems (ITS) have focused on motorized vehicles and large car manufacturers are now starting to implement the resulting standards. With bikes gaining more and more popularity and, thus, a share in accidents, it is important to consider the special safety needs of cyclists. We propose a way of extending established ITS standards with new fields meeting cyclists needs while keeping a maximum of backwards compatibility to already deployed ITS vehicles. We demonstrate this approach by presenting examples for extensions of the ETSI ITS-G5 CAM and DENM message formats.