Measurement system for determining the wheel alignment of a vehicle with at least two axles, comprising: - a plurality of first measuring units, each one adapted to be fixed to a wheel of the vehicle; - a processing unit adapted to receive data generated by said plurality of first measuring units and to determine the wheel alignment of the vehicle whereon such first measuring units have been associated; said first measuring units being of the optical type; each one of said first measuring units comprising at least one optical assembly; said measurement system being characterized in that: - it comprises two second measuring units adapted to be placed on a reference plane, whereon the vehicle itself can lie, each one being adapted to be arranged on one side of the vehicle; - said two second measuring units being of the optical type, and each second measuring unit comprising at least two optical assemblies (52, 54), wherein: ∘ a first optical assembly being adapted to at least be aligned with another first optical assembly comprised in the other second measuring unit, in order to define a virtual axle; ∘ a second optical assembly being adapted to take measurements relative to a respective first measuring unit; - said processing unit being adapted to receive also the data generated by said second measuring units, such data being used for determining the wheel alignment of the vehicle. - a plurality of first measuring units, each one adapted to be fixed to a wheel of the vehicle; - a processing unit adapted to receive data generated by said plurality of first measuring units and to determine the wheel alignment of the vehicle whereon such first measuring units have been associated; said first measuring units being of the optical type; each one of said first measuring units comprising at least one optical assembly; said measurement system being characterized in that: - it comprises two second measuring units adapted to be placed on a reference plane, whereon the vehicle itself can lie, each one being adapted to be arranged on one side of the vehicle; - said two second measuring units being of the optical type, and each second measuring unit comprising at least two optical assemblies (52, 54), wherein: ∘ a first optical assembly being adapted to at least be aligned with another first optical assembly comprised in the other second measuring unit, in order to define a virtual axle; ∘ a second optical assembly being adapted to take measurements relative to a respective first measuring unit; - said processing unit being adapted to receive also the data generated by said second measuring units, such data being used for determining the wheel alignment of the vehicle. - it comprises two second measuring units adapted to be placed on a reference plane, whereon the vehicle itself can lie, each one being adapted to be arranged on one side of the vehicle; - said two second measuring units being of the optical type, and each second measuring unit comprising at least two optical assemblies (52, 54), wherein: ∘ a first optical assembly being adapted to at least be aligned with another first optical assembly comprised in the other second measuring unit, in order to define a virtual axle; ∘ a second optical assembly being adapted to take measurements relative to a respective first measuring unit; ∘ a first optical assembly being adapted to at least be aligned with another first optical assembly comprised in the other second measuring unit, in order to define a virtual axle; ∘ a second optical assembly being adapted to take measurements relative to a respective first measuring unit; - said processing unit being adapted to receive also the data generated by said second measuring units, such data being used for determining the wheel alignment of the vehicle.