A method, system, and computer program product is provided, for example, for assisting a user of the vehicle in following a prescribed speed limit while travelling in the vehicle. The method comprises providing a speed limit related recommendation to the user of the vehicle. The method further comprises receiving an image data representing a posted sign, in a vicinity of the vehicle, the image data being detected by one or more image capturing devices. Additionally, the method comprises processing the image data received to determine an observed numerical value. The method further comprises calculating, by a processor, a sign reliability factor based on a function of at least the observed numerical value, a historic mean of one or more vehicle speeds at the time of sign observation and a standard deviation of the one or more vehicle speeds at the time of sign observation. Additionally, the method may include providing data for an indication of the speed limit to be followed by the vehicle.