A shock absorber includes a resilient element; a gear set comprising a first non-return gear and a second non-return gear; and an electric generator driven by the first non-return gear to generate a power when the resilient element is compressed and driven by the second non-return gear when the resilient element is loosened. The BWA system configures one or more areas of Access Control Routers as one Multicast and Broadcast Service zone. The reinforcing member is formed to extend over the electric power storage apparatus so as to bridge between the driver’s seat and the passenger’s seat. The network address of each service provider is stored in the data storage in correlation with the service to which the provider is associated.