A method of operating a vehicle map service, the method comprising: accessing, by one or more computing devices, vehicle map service data comprising information associated with a geographic area and one or more sensor observations of a vehicle, wherein the vehicle map service data is based at least in part on a vehicle map service protocol specifying a plurality of layers associated with one or more portions of the vehicle map service data to which each of a plurality of client systems is subscribed, wherein the plurality of layers corresponds to a plurality of layer versions, and wherein each of the plurality of layer versions is indicative of a data format used by each of the plurality of layers respectively; determining, by the one or more computing devices, the plurality of layers to which each of the plurality of client systems is subscribed, wherein determining the plurality of layers to which each of the plurality of client systems is subscribed comprises: determining, by the one or more computing devices, based at least in part on the plurality of layer versions corresponding to the plurality of layers, when a layer of the plurality of layers is compatible with each of the plurality of client systems, wherein each of the plurality of client systems is subscribed only to the plurality of layers that are compatible with the respective client system of the plurality of client systems; and providing, by the one or more computing devices, to each of the plurality of client systems, access to the plurality of layers to which the respective client system of the plurality of client systems is subscribed, wherein access to the plurality of layers comprises authorization to send or receive one or more portions of the vehicle map service data associated with a corresponding layer of the plurality of layers. accessing, by one or more computing devices, vehicle map service data comprising information associated with a geographic area and one or more sensor observations of a vehicle, wherein the vehicle map service data is based at least in part on a vehicle map service protocol specifying a plurality of layers associated with one or more portions of the vehicle map service data to which each of a plurality of client systems is subscribed, wherein the plurality of layers corresponds to a plurality of layer versions, and wherein each of the plurality of layer versions is indicative of a data format used by each of the plurality of layers respectively; determining, by the one or more computing devices, the plurality of layers to which each of the plurality of client systems is subscribed, wherein determining the plurality of layers to which each of the plurality of client systems is subscribed comprises: determining, by the one or more computing devices, based at least in part on the plurality of layer versions corresponding to the plurality of layers, when a layer of the plurality of layers is compatible with each of the plurality of client systems, wherein each of the plurality of client systems is subscribed only to the plurality of layers that are compatible with the respective client system of the plurality of client systems; and providing, by the one or more computing devices, to each of the plurality of client systems, access to the plurality of layers to which the respective client system of the plurality of client systems is subscribed, wherein access to the plurality of layers comprises authorization to send or receive one or more portions of the vehicle map service data associated with a corresponding layer of the plurality of layers. determining, by the one or more computing devices, based at least in part on the plurality of layer versions corresponding to the plurality of layers, when a layer of the plurality of layers is compatible with each of the plurality of client systems, wherein each of the plurality of client systems is subscribed only to the plurality of layers that are compatible with the respective client system of the plurality of client systems; and providing, by the one or more computing devices, to each of the plurality of client systems, access to the plurality of layers to which the respective client system of the plurality of client systems is subscribed, wherein access to the plurality of layers comprises authorization to send or receive one or more portions of the vehicle map service data associated with a corresponding layer of the plurality of layers.