This document provides recommendations of safety message minimum performance requirements between a Vulnerable Road User (VRU) and a vehicle. It addresses the transmission of Personal Safety Messages (PSM) from road user devices carried by pedestrians, bicycle riders and public safety personnel, to provide driver and vehicle system awareness and potentially offer safety alerts to VRUs.
This document includes the recommendation of standards profiles, function descriptions and minimum performance requirements for transmitting the SAE J2735-defined PSM  over a Dedicated Short Range Communications (DSRC) Wireless communication link as defined in the Institute of Electrical and Electronics Engineers (IEEE) 1609 and the IEEE 802.11 Standards [-]. While other wireless media may be used to deliver the PSM, DSRC is explicitly assumed in this document, because of anticipated regulatory ruling in the United States and other countries requiring vehicles to be equipped with a DSRC-based safety system using V2V communication.
This recommended practice is limited at this time to communications between the VRU device carried by walking pedestrians and DSRC equipped vehicles. Later versions may incorporate improvements based on field experience with this recommended practice and may include other provisions for communicating with other DSRC equipped devices, and with other VRUs.
According to NHTSA, in 2012 traffic crashes in the United States claimed 4743 pedestrian fatalities and resulted in 76000 pedestrian injuries. NHTSA reports that 726 pedalcyclists were killed and 49000 were injured in traffic crashes. In addition, in 2012,106 road workers were killed by traffic crashes in the United States. Vehicle-to-Vehicle (V2V) safety systems using Dedicated Short Range Communications (DSRC) have been researched and have been undergoing standardization for more than a decade. In the near future deployments are likely. Leveraging these developments and prospective deployment, research has been conducted using DSRC portable devices to extend the potential safety benefit to Vulnerable Road Users (VRU) such as pedestrians, bicyclists and road workers. In order to achieve interoperability between vehicle-based and portable DSRC safety devices for experimental use, there is a need to establish a VRU safety message minimum performance recommendations to support VRU safety applications.