The present subject matter relates to a method and a roadside unit for generating a digital record of a vehicle in a road toll system, comprising: capturing an image of the vehicle on a roadway; data-compressing the image depending on at least one of a confidence level obtained from the image for one or more characters therein by means of OCR, and a contrast parameter obtained from the image or a region of interest therein or a section of the latter, to generate the digital record; and sending the digital record from the roadside unit to a data center of the road toll system.