###### Abstract  
For occupant safety in vehicular networks, emergency messages derived from vehicular incidents should be exchanged only during their validity period and in zones containing involved entities. Problems arise for mobile entities in vehicular networks that change their location over time, where data may be further communicated in out-of-context space and time. Current solutions extend from the naive assumption of notifying every entity in the network about emergencies with data flooding and clusters and by means of specific communication only in the affected zones--geo-routing--of incidents' relative data. However, delivering useless data to uninvolved entities results in wasted resources and more overheads in the former cases and the work of obtaining knowledge and secondary site services from neighbors in the latter. In this paper, we propose that the common task of disseminating emergency messages for occupant safety among entities should only be communicated only where and when useful, namely, if spatio-temporal constraints apply regarding those incidents. Our solution is inspired by the communication of working social insects that exchange data through pheromones regardless of closeness or knowledge among colony members for food retrieval. The results show that communication based on space-time constraints makes better use of resources than other solutions. v 1 (2025) 11 February 2025 26 February 2025 26 February 2025 26 February  
data are communicated: distant or outdated data are received and then discarded by most entities with inherent channel bandwidth, buffer, and processing misuse [8]. In addition, traditional communication paradigms are still in place: static network architectures, the requirement for prior knowledge of communicating entities, assumed universal mobile global third-party communication and/or location services, human or manual involvement, and the largely time-only design of communication protocols. Contrary to current approaches, we propose the use of emerging vehicular networks with dedicated infrastructures in dynamic urban environments and the delivery of only useful data under the premise that spatio-temporal constraints define both the useful data and the receivers that participate in the common task of the disseminating of emergency messages. Moreover, in nature, social insects base their communication and coordination on indirect pheromone messages, called stigmergy, such as in ants [9; 10]. Therefore, any individual not having knowledge about other colony members is not an obstacle for successful communication; in this case, regarding food retrieval, these individuals are secondary, while achieving the common benefit is primary. In our proposed solutions, the communicating entities and the EMS are prioritized in the same way, as described in the literature as task-oriented communication [11; 12]. This biological behavior inspired our EMS solution: failed or stranded mobile entities report to fixed entities located at crossroads acting as intermediaries. In turn, mobile entities are aware of the problem because they consume incident-related data--similar to a pheromone--from fixed entities. Data in the form of pheromones held by fixed entities describe close and recent incidents that only entities defined by space-time constraints are able to consume. Eventually, in a passive manner, a pheromone expires if it is not reaffirmed by the entity that provoked the incident, thereby marking the end of the incident. Note that this behavior is actually a spatio-temporal behavior, since representative data in the pheromone are related to the location of food sources or incidents and are valid only during certain periods of time; in the literature, this is known as degradation [13; 14]. Namely, data are only useful if they are communicated in the space-time they are created, while communicated data are only useful if they describe the close and recent space-time context.