Road construction machine, especially a paving machine or a milling machine, comprising a levelling system, the road construction machine comprising a chassis and a tool, the levelling system comprising: - a first height sensor arrangement (3L/R, 40L/R) coupled to a first side of the tool or to a first side (10L/R) of the chassis of the machine and configured to determine a first distance information (DL/DR) as first actual value for a distance to an underground or to an applied layer in reference to a reference point belonging to the first side of the tool or to the first side (10L/R) of the chassis; and - a second height sensor arrangement (3L/R, 40L/R) coupled to the second side of the tool or to a second side (10L/R) of the chassis and configured to determine a second distance information (DL/DR) serving as second actual value for a distance to the underground or to the applied layer in reference to the reference point belonging to the second side of the tool or to the second side (10L/R) of the chassis; and - a first controller (5L/R, 45L/R) comprising a first independent controller loop configured to control a height position of the first side of the tool or of the machine chassis based on the first actual value and a first setpoint for the height position of the first side of the tool or of the chassis; and - a second controller (5L/R, 45L/R) comprising a second independent controller loop independent from the first independent controller loop and configured to control a height position of the second side of the tool or of the chassis based on the second actual value and a second setpoint for the height position of the second side of the tool or of the chassis; and - an additional sensor (2, 200, 300, 400) coupled to the tool or the chassis and configured to determine an actual reference value for either the first or the second side of the tool or either the first or the second side of the chassis, the actual reference value describing a height position of either the first or the second side of the tool or either the first or the second side of the chassis; characterized in that the first and the second controllers (5L/R, 45L/R) are configured to adapt the setpoint based on the actual reference value of the additional sensor (2, 200, 300, 400), whereby a setpoint adaption performed by the first or the second controller (5L/R, 45L/R) takes place only either on the first side or the second side of the tool or of the chassis. - a first height sensor arrangement (3L/R, 40L/R) coupled to a first side of the tool or to a first side (10L/R) of the chassis of the machine and configured to determine a first distance information (DL/DR) as first actual value for a distance to an underground or to an applied layer in reference to a reference point belonging to the first side of the tool or to the first side (10L/R) of the chassis; and - a second height sensor arrangement (3L/R, 40L/R) coupled to the second side of the tool or to a second side (10L/R) of the chassis and configured to determine a second distance information (DL/DR) serving as second actual value for a distance to the underground or to the applied layer in reference to the reference point belonging to the second side of the tool or to the second side (10L/R) of the chassis; and - a first controller (5L/R, 45L/R) comprising a first independent controller loop configured to control a height position of the first side of the tool or of the machine chassis based on the first actual value and a first setpoint for the height position of the first side of the tool or of the chassis; and - a second controller (5L/R, 45L/R) comprising a second independent controller loop independent from the first independent controller loop and configured to control a height position of the second side of the tool or of the chassis based on the second actual value and a second setpoint for the height position of the second side of the tool or of the chassis; and - an additional sensor (2, 200, 300, 400) coupled to the tool or the chassis and configured to determine an actual reference value for either the first or the second side of the tool or either the first or the second side of the chassis, the actual reference value describing a height position of either the first or the second side of the tool or either the first or the second side of the chassis;