Abstract: Personnel and vehicle collision avoidance devices configured to be used in collision avoidance systems are disclosed. The collision avoidance devices are configured to be aware of the context (e.g. position, location, state, status, etc.) in which the person or vehicle is. This awareness allows the devices to avoid transmitting non-hazardous proximity warnings when the context does not warrant the transmission of proximity warnings, and to transmit special critical proximity warnings when the context warrants the transmission of such proximity warnings. To detect the context, the devices comprise one or more context-awareness mechanisms (e.g. user input interfaces, sensors, infra-red receivers, etc.), each of which being capable of detecting one or more particular contexts. A collision avoidance system comprising these personnel and vehicle collision avoidance devices is also presented.