A method of manufacturing a structural element for manufacturing vehicles, comprising at least the steps of: i) preparing a structural element (2, 3, 4, 5, 27, 30) of the vehicle internally provided with a hollow space through the steps of: - providing a pre-formed first shaped plastic panel (6, 20); - providing a pre-formed second shaped plastic panel (9, 21); - arranging conductive tracks defining at least part of an electrical equipment of the vehicle on an inner face (8,23,11,25) of at least one of the shaped panels (6,20,9,21) by applying said conductive tracks on at least one sheet and laying/gluing said sheet on the inner face (8, 23) of the first shaped panel (6, 20) and/or inner face (11, 25) of the second shaped panel (9, 21); - and, after said arranging conductive tracks on an inner face (8,23,11,25) of at least one of the shaped panels (6,20,9,21), coupling the first shaped panel (6, 20) to the second shaped panel (9, 21) so as to define the structural element (2, 3, 4, 5, 27, 30) of the vehicle, wherein confined between the first shaped panel (6, 20) and the second shaped panel (9, 21) is the hollow space; and ii) subsequently filling said hollow space with a foamed material. i) preparing a structural element (2, 3, 4, 5, 27, 30) of the vehicle internally provided with a hollow space through the steps of: - providing a pre-formed first shaped plastic panel (6, 20); - providing a pre-formed second shaped plastic panel (9, 21); - arranging conductive tracks defining at least part of an electrical equipment of the vehicle on an inner face (8,23,11,25) of at least one of the shaped panels (6,20,9,21) by applying said conductive tracks on at least one sheet and laying/gluing said sheet on the inner face (8, 23) of the first shaped panel (6, 20) and/or inner face (11, 25) of the second shaped panel (9, 21); - and, after said arranging conductive tracks on an inner face (8,23,11,25) of at least one of the shaped panels (6,20,9,21), coupling the first shaped panel (6, 20) to the second shaped panel (9, 21) so as to define the structural element (2, 3, 4, 5, 27, 30) of the vehicle, wherein confined between the first shaped panel (6, 20) and the second shaped panel (9, 21) is the hollow space; and - providing a pre-formed first shaped plastic panel (6, 20); - providing a pre-formed second shaped plastic panel (9, 21); - arranging conductive tracks defining at least part of an electrical equipment of the vehicle on an inner face (8,23,11,25) of at least one of the shaped panels (6,20,9,21) by applying said conductive tracks on at least one sheet and laying/gluing said sheet on the inner face (8, 23) of the first shaped panel (6, 20) and/or inner face (11, 25) of the second shaped panel (9, 21); by applying said conductive tracks on at least one sheet and laying/gluing said sheet on the inner face (8, 23) of the first shaped panel (6, 20) and/or inner face (11, 25) of the second shaped panel (9, 21); - and, after said arranging conductive tracks on an inner face (8,23,11,25) of at least one of the shaped panels (6,20,9,21), coupling the first shaped panel (6, 20) to the second shaped panel (9, 21) so as to define the structural element (2, 3, 4, 5, 27, 30) of the vehicle, wherein confined between the first shaped panel (6, 20) and the second shaped panel (9, 21) is the hollow space; and ii) subsequently filling said hollow space with a foamed material.