A robotic vehicle configured for spreading an aqueous solution such as deicing solution, fertilizer, weed killer, pre-emergent, insecticide, or water over a service area, the robotic vehicle comprising: a chassis supporting a storage tank in which the aqueous solution is contained; a mobility assembly operably coupled to the chassis to provide mobility for the robotic vehicle about a service area; a positioning module configured to provide guidance for the robotic vehicle during transit of the robotic vehicle over the service area; a spray assembly operably coupled to the storage tank to spray the aqueous solution during the transit of the robotic vehicle over the service area; and control circuitry operably coupled to the spray assembly and positioning module, the control circuitry being configured to adjust characteristics of the spray assembly or speed of the mobility assembly to control an amount of the aqueous solution applied to the service area (20,) the spray assembly comprising a pump operably coupled to the storage tank, a nozzle operably coupled to the storage tank via the pump to generate a spray pattern for spraying the aqueous solution responsive to operation of the pump as the robotic vehicle transits the service area, and a flow controller, wherein the flow controller includes processing circuitry, and is configured to adjust the characteristics of the pump or speed of the robotic vehicle to control the amount of the aqueous solution applied to the service area; characterised in that the spray assembly comprises a nozzle interface that is configured to measure a differential pressure across an orifice of a known diameter of the nozzle of the spray assembly to determine a flow rate of the aqueous solution; and the nozzle interface comprising a reed switch or micro-switch operably coupled to a component in a flow path of the aqueous solution exiting the nozzle to positively confirm flow of the aqueous solution from the nozzle via a feedback signal provided to the control circuitry. a chassis supporting a storage tank in which the aqueous solution is contained; a mobility assembly operably coupled to the chassis to provide mobility for the robotic vehicle about a service area; a positioning module configured to provide guidance for the robotic vehicle during transit of the robotic vehicle over the service area; a spray assembly operably coupled to the storage tank to spray the aqueous solution during the transit of the robotic vehicle over the service area; and control circuitry operably coupled to the spray assembly and positioning module, the control circuitry being configured to adjust characteristics of the spray assembly or speed of the mobility assembly to control an amount of the aqueous solution applied to the service area (20,) the spray assembly comprising a pump operably coupled to the storage tank, a nozzle operably coupled to the storage tank via the pump to generate a spray pattern for spraying the aqueous solution responsive to operation of the pump as the robotic vehicle transits the service area, and a flow controller, wherein the flow controller includes processing circuitry, and is configured to adjust the characteristics of the pump or speed of the robotic vehicle to control the amount of the aqueous solution applied to the service area; characterised in that the spray assembly comprises a nozzle interface that is configured to measure a differential pressure across an orifice of a known diameter of the nozzle of the spray assembly to determine a flow rate of the aqueous solution; and the nozzle interface comprising a reed switch or micro-switch operably coupled to a component in a flow path of the aqueous solution exiting the nozzle to positively confirm flow of the aqueous solution from the nozzle via a feedback signal provided to the control circuitry.