A road-side network node (NN1; NN3; NN5; NN6) for operation in an adhoc radio communications network, VANET, the road-side network node (NN1; NN3; NN5; NN6) comprising a processor, a memory, a radio module, and an antenna, the road-side network node being configured to: - determine data to be transmitted via an adhoc radio channel; - determine or provide an adhoc time slice reserved for transmissions via the adhoc radio channel, AHCH, in the adhoc radio communications network, VANET; - synchronize a local clock of the road-side network node to a common time source signal for other road-side network nodes; - determine expected boundaries of an a-priori known time duration of a frame unit of a cell-supported radio communications network, CNET, in dependence on a clock signal of the local clock, wherein the adhoc radio channel, AHCH, and a sidelink radio channel, SLCH, provided by the cell-supported radio communications network, CNET, operate in the same or overlapping frequency range as one another; - determine a status of the adhoc radio channel, wherein the status is an idle/busy status and/or a status indicating a contiguous transmission; - determine an occupancy of the adhoc radio channel in dependence on the expected boundaries and in dependence on the status of the adhoc radio channel; wherein the road-side network node being further configured to determine the occupancy as a first occupancy of the adhoc radio channel with adhoc traffic, when the status indicates a contiguous transmission with at least one transmission boundary not being an expected boundary and determine the occupancy as a second occupancy of the adhoc radio channel with non-adhoc traffic, when the idle/busy status indicates a contiguous transmission with both transmission boundaries being an expected boundary, - determine the adhoc time slice in dependence on the occupancy; and - start a transmission of the data via the adhoc radio channel during the adhoc time slice. - determine data to be transmitted via an adhoc radio channel; - determine or provide an adhoc time slice reserved for transmissions via the adhoc radio channel, AHCH, in the adhoc radio communications network, VANET; - synchronize a local clock of the road-side network node to a common time source signal for other road-side network nodes; - determine expected boundaries of an a-priori known time duration of a frame unit of a cell-supported radio communications network, CNET, in dependence on a clock signal of the local clock, wherein the adhoc radio channel, AHCH, and a sidelink radio channel, SLCH, provided by the cell-supported radio communications network, CNET, operate in the same or overlapping frequency range as one another; - determine a status of the adhoc radio channel, wherein the status is an idle/busy status and/or a status indicating a contiguous transmission; - determine an occupancy of the adhoc radio channel in dependence on the expected boundaries and in dependence on the status of the adhoc radio channel; wherein the road-side network node being further configured to determine the occupancy as a first occupancy of the adhoc radio channel with adhoc traffic, when the status indicates a contiguous transmission with at least one transmission boundary not being an expected boundary and determine the occupancy as a second occupancy of the adhoc radio channel with non-adhoc traffic, when the idle/busy status indicates a contiguous transmission with both transmission boundaries being an expected boundary, - determine the adhoc time slice in dependence on the occupancy; and - start a transmission of the data via the adhoc radio channel during the adhoc time slice.