Mobile networks have proved to be an attractive solution to support emergency services, due to their inherent mobility, which requires flexible and yet efficient communication. However, the management of resources in slices in a 5G network is still made static and with no mobility information and prediction. This paper proposes the integration of a 5G network platform and a city mobility network, which allows 5G network resources to be allocated dynamically and in advance according to the users mobility and their needs. This mobility and network integration is important for different types of services, from infotainment to emergency. The prediction of the mobility and location through the mobility network provides the knowledge for a 5G cellular network to dynamically reserve the required network slicing resources. This approach has been tested in real road scenarios and vehicles covered by 5G. The results show that the solution guarantees the required resources, reserved in a proactive and predictive approach, both to optimize the resources of one base station, and to optimize resources between base stations, offering the required quality to the services.