From this sign onward, what is the maximum speed on a road with three lanes per direction?

The sign shown in the question indicates the entry into a built-up area, so from that point on, the traffic regulations applicable to urban roads apply. The general speed limits on urban roads, in the absence of specific signage, are as follows depending on the characteristics of the carriageway: a) 20 km/h on roads with a single shared platform for carriageway and pavement. b) 30 km/h on roads with a single lane per direction of travel. c) 50 km/h on roads with two or more lanes per direction of travel. (40 km/h for vehicles transporting dangerous goods) For these purposes, lanes reserved for the circulation of certain users or for the exclusive use of public transport shall not be counted. These limits may be reduced or increased by the Municipal Authority subject to specific signage. On through roads within towns, a limit of 50 km/h is set for all types of vehicles, except for vehicles transporting dangerous goods, for which it shall be 40 km/h. This limit may be reduced by agreement between the Municipal Authority and the road authority, subject to specific signage.