Braking system for vehicles comprising - a first brake group and a second brake group intended to be installed on the same axle of a vehicle or on separate axles of a vehicle, - the first brake group comprising a first braking device, first electro-hydraulic actuator means operatively connected to the first braking device by means of a first hydraulic actuation duct, - the second brake group comprising a second braking device, second electro-hydraulic actuator means operatively connected to the second braking device by means of a second hydraulic actuation duct, - an interconnection branch between the first and the second hydraulic actuation ducts (24,36), provided with a control valve, - at least one control unit for the brake groups (8, 12), operatively connected to the electro-hydraulic actuator means (20,32) and to the control valve, - the control unit being programmed to actuate the control valve so as to: - disconnect the first and second hydraulic actuation ducts (24,36) from each other in the event of standard operation or absence of malfunctions in the brake groups (8,12), - fluidically connect the first and second hydraulic actuation ducts (24,36) to each other in the event of an electrical fault in a brake group (8,12), characterized in that, in order to obtain a parking brake function, the at least one control unit (60', 60'') is programmed to perform the following sequence: - open the control valve and move a first float of the first electro-hydraulic actuator means into the forward or braking position, the pressure exerted in the second actuation duct moving a second float (48") of the second electro-hydraulic actuator means into the rearward position, - command the closing of the control valve, - move the first float rearward, - command the opening of the control valve, to equalize the pressures in the first and second hydraulic actuation ducts (24, 36). - a first brake group and a second brake group intended to be installed on the same axle of a vehicle or on separate axles of a vehicle, - the first brake group comprising a first braking device, first electro-hydraulic actuator means operatively connected to the first braking device by means of a first hydraulic actuation duct, - the second brake group comprising a second braking device, second electro-hydraulic actuator means operatively connected to the second braking device by means of a second hydraulic actuation duct, - an interconnection branch between the first and the second hydraulic actuation ducts (24,36), provided with a control valve, - at least one control unit for the brake groups (8, 12), operatively connected to the electro-hydraulic actuator means (20,32) and to the control valve, - the control unit being programmed to actuate the control valve so as to: - disconnect the first and second hydraulic actuation ducts (24,36) from each other in the event of standard operation or absence of malfunctions in the brake groups (8,12), - fluidically connect the first and second hydraulic actuation ducts (24,36) to each other in the event of an electrical fault in a brake group (8,12), - disconnect the first and second hydraulic actuation ducts (24,36) from each other in the event of standard operation or absence of malfunctions in the brake groups (8,12), - fluidically connect the first and second hydraulic actuation ducts (24,36) to each other in the event of an electrical fault in a brake group (8,12), - open the control valve and move a first float of the first electro-hydraulic actuator means into the forward or braking position, the pressure exerted in the second actuation duct moving a second float (48") of the second electro-hydraulic actuator means into the rearward position, - command the closing of the control valve, - move the first float rearward, - command the opening of the control valve, to equalize the pressures in the first and second hydraulic actuation ducts (24, 36).