Emergency services play an important role in the intelligent transportation systems based on mobile communication networks in smart cities, but the characteristics of Vehicular Ad-hoc Networks (VANETs), such as high mobility, intermittent connectivity, scalability and constant changes in network topology make this type of message dissemination a challenge. To improve emergency message dissemination between vehicles, we are proposing strategies that take advantage of the location, direction, speed, number of vehicles' neighbors and characteristics of the region of the city, so that the message reaches all vehicles in the shortest time with the lowest network overhead. To show the effectiveness of our strategies, we have been deployed a platform composed by SUMO, a vehicular network emulator and a connectivity aggregation tool. Our results with this platform show a delivery rate between 92% and 100% at various densities and vehicle speeds, for various zone sizes of relevance and range of the communication technology.